Yeah, I like it as well. If I set up VFD + CVT + backgear, I could near continuous speed from 3000 done to about 10 RPM, with more grunt than a rutting sperm whale.
I definitely second this. It's an old machine. If you can get it working on the software side then keep the variator and gearbox. Electromechanics are cool and servo drives are boring. :)
When I was researching this, I was really surprised that the PW110G is not significantly lighter than the Leap-1A. One of the benefits of the high RPM core and LP should be a much lighter engine. Will be interesting to see if that gearbox pays off for them.
@@RotarySMP Increased fan diameter means bigger diameter fan shroud, which not only is getting heavier because of size, but also needs to contain blade-outs of the fan blades, that are also getting bigger and heavier. There is a practical limit to increasing the bypass ratio mostly dictated by the structural weight. This is why engine manufacturers are looking into unducted fans and propfans again in recent years.
If engine builders were thinking like that, we would still be using turbojets with horrible fuel economy. Progress brings complexity, it's unavoidable.
@@stefanpariyski3709 I just find it fascinating that GE can keep ahead of both Rolls 3 spool designs and Pratt's GTF with a very conventional 2 spool designs. GE has invested heavily in process tech like CMC's and metalic additive manufacturing
I say keep it. It's going to make the wife happy, and if it actually dies you can justify a new motor much more easily. And software control should also not be a huge problem, depending on how LinuxCNC manages that. Also, that bit about the turbines was really interesting, I hope you keep those segments coming!
Thanks for the crash course on jet engines - was an interesting new look at them. I would keep the old motor and related hardware until it no longer goes - it may still surprise you :-)
Perfectly complete episode….. vinegar baths, turbine engine development, 3ph motor/drivetrain graphs, cleaning the workbench…… it’s got it all. Since you asked for votes, I would start skipping one latte every week at Starbucks and deposit that money in a new motor piggy bank, and drive on. If the motor bearings are good and your not planning to put this lathe into 24/7 production mode, this original motor will likely outlast you and your heirs will inherit a nice bonus account. Questions - Was that apple cider vinegar? How eye-wateringly fragrant does the workshop get after 48th hours of evaporating vinegar? Does that vinegar air tend to rust other metal nearby? Maybe you covered the pool with another bag? Would 5 of the smallest standoffs (like M3 nuts), one at each corner and one in the middle, be sufficient to etch both sides at once without needing much more volume?
That was cheap and nasty supermarket own brand vineagar. 60c a litre. The Ions in the air dont rust everything as badly as the time I did fast mill scale removal with HCl, and split a bunch on the floor.
m3 nut is too flat, the bag would touch the steel , but even if it would be enough, 1mm thickness @ 1 square meter area is 1 litre of volume.. so even prepping up with m3 nuts would consume the 1l bottle of vinegar without having enough vinegar on top.
@@robertjung8929 If I had put paper towels on top, it probably would have keep it moist, avoiding the pitting. Not like it really matters. It is only for screwing the electic to.
I was a GSE/AGE mechanic in the USAF. Your explanation of a GTC and the design changes/differences was a thing of beauty. I worked with a power unit we called a -60 it had 3 phase 120 VAC 400hz power. It had a two stage compressor and a single turbine wheel.
This was a great episode, thank you. I learned the vinegar/mill scale trick from one of your earlier videos and have used it a few times - great tip. I loved the tangent talk on jet engines too, so thanks for that. My vote for the motor is defo try and use the existing power train. Really only because that's what I would do, not because I have special knowledge/experience. I don't mind if you ignore this and go for a new motor, I'm just one of the Heathers that enjoys your channel. Good luck with whatever option you go with. - Heather
I bought an old wood lathe at an estate sale. Thought I got good deal. The guy said it just needed a pulley. I didn't know much back then and know less now, so I bought it. Turns out I needed a special pulley that I had never heard of before. A reeves pulley was my introduction to variable speed pulleys. Well. I never have found a replacement for that pulley. I 3D printed one that fit the shaft. I fell apart when I tried it out. Live and learn. That's wild about the motor to run the variable pulley width. Cools stuff. Thanks for the lesson. And this lesson is modern time in a nutshell. Software may have eaten the world, but hardware had a great appetizer!
My lathe had a similar system. I use my every day and it is very important for the company. So I decided to make it simple. Took the variator off, and the back gear. Made a pulley reduction. And used a high speed and considerable more powerful motor with a VFD. But if it was a machine for casual use. I probably would had kept all original like you did on the maho.
I love the aviation interludes my late father was a avionics engineer on RADAR - lightnings, buccaneers and lastly sea harriers so I grew up with aircraft and his explanations on how things worked.
That's a interesting side bar about the turbo fan. And I agree with your comment on not having anything to break, I always say, "there's nothing to go wrong when there's nothing to go wrong."
Pratt have tried this before (PW8000). I heard that was their gearbox design, and ended up not commercialised. That is where I heard that MTU designed the PW1000 gearbox. If they can make that work, it should really squeeze the competition.
While the motor was out I would considered removing the gearbox and pulley system but I would have opted for least amount of work and reinstalled everything just like you did, kicking the can down the road. Thanks for the vinegar explanation.
@@RotarySMP I was thinking... You mentioned 5 x contactors. Have you considered a manual two position lots of poles industrial switch to change the motor between start & delta?
For mill scale removal I use those purple and spongy "cleaning discs" for angle grinders. They are fast, cheap, don't bite into the base metal, and don't clog up like flap disks do. Nice video, really appreciate the info on turbines! :D
I replaced the motor on my lathe with a mining spec abb 1hp motor, not even sure what the insulation class is but it's been running fine on an import VFD. IP65 rated, I can hose it down if it gets warm 😜
Wow what a great episode!! For what its worth ive been running a Colchester Student lathe with its original 3 phase motor 2.2 Kw for approx 20 years with an SEW eurodrive VFD. Single to three phase setup.haven't killed it yet, but only a small amount of weekend warior work. The lathe was ex Wellington polytec. Only having one fifth of the torque at low speed means you might have to take a smaller deepth of cut, but more importantly the cutting speed will be corect. Unless your putting this thing into production of large diameter parts and time is critcal.
My setup is only manual lathe so no issues with noise. There is no shielding on the cable, but the VFD does make the radio Fuss a little. With a plug swap system for power and control this VFD also runs an old Bridgeport mill(1.5 horsepower original motor) It has also lived a long time. I also had to convert the motors from star to delta or vice versa, i cant remember 20 years ago.
Personally, if it were for me, I'd keep the belt drive and install a few contactors. Linux CNC can handle them easily, no buggering about with variators, you get continuous speed variation with no electrical noise, and enormous torque. Not to mention that replacing a belt is far cheaper than replacing a VFD.
@@RotarySMP Ah, my bad wording. Keep the belt drive *variator*, and drive the electrics how they were originally designed. New contactors driven by whatever voltage your linuxcnc board can drive (and is already driving elsewhere), obvs. No buggering about VFDs (in my defence, "variator" is what they're called over here in frogland)... It's a very robust solution.
@@wibblywobblyidiotvision I'll second this idea. Note that this lathe has somewhat the opposite condition of the P&W engine: it and countless other machines have run just fine with a variable belt drive for decades, and the VFD is the unproven technology.
@@lwilton VFDs are hardly unproven. There are millions of them running around the world and have done so for decades. Not as long as variable belt drives but there are millions or billions of hours of accumulated operation.
I like the mechanical speed variator! Especially since it can be controlled through CNC. My mill at work I use is a CNC conversion type knee mill and it doesn't have a CNC controlled variator but otherwise I really like the variator! Unless its a safety hazard I would leave the original motor for as long as possible and just replace that with a VFD compatible one while leaving the mechanical variator if the old motor dies.
Love it! I flew the Pratt F100's and GE110's in the Air Force. Also, I flew the JT8 series in the airlines. GREAT ENGINES. Our Airbus fleet has the IAE engines. I didn't get to fly them with CFM engines. Keep up the great work......
I have an similar age 3kW manual lathe that I'm running on a VFD and it hasn't killed the motor yet. With the caveat that I don't know if it's the original motor but it probably is, there was only one prior owner of the lathe and they didn't use it much.
Thanks. That is a good data point. It seems Schaublin generally bought high end hardware for this machine, so hoefully that goes for that motor as well.
@@RotarySMP Here's another (not very close) one: I worked with an Italian packaging machine for a while. Similar age, similar motor size, different mechanical load. The motor died from the VFD while I was there. It was used for many years with that though. It functionally replaced the manually adjusted CVT after a large, custom spring broke in it multiple times.
Rolls Royce is building Ultrafan which should have a gearbox too. Also composite fan blades for weight reduction as compared to titanium ones. The bigger engine you make the bigger the centrifugal forces you need to deal with. Fun fact Tupolev Tu-95 tips of the blades are turning faster than speed of sound making it apparently very loud plane
RR tried composite blades first. The development was part of what pushed them into receiver ship in the1970's. It took GE also about a decade of research to perfect the composite blades used on all their large turbofans since the GE90. There are a number of advantages, including that the tend to pulverise in a blade out event making containment easier. I heard an AN-22 on approach to Vienna about a decade ago. They have the same NK-12's as the bear. It is a very distinct sound, unlike any other plane, and that was only at approach power. Interesting fact, is that the NK-12 was designed by an Austrian, Ferdinand Brantner, who was a Junkers design engineer deported to the Soviet Union after the war.
With proper output filtering you can get rid of the Output spikes from the VFD. Some just use a shit load of "ferrite" or better noncrystalline Toroids in CMC configuration. There are "proper" Filter modules commercially available but they are not cheap. Common mode Cokes are also necessary to protect your motors bearings.
keep the motor and run it until death do you part. btw i do like your 20min video format much better than the shorter ones, while more compressed content. keep up the good work. Greetings from a former aircraft mechanic
For the vineger. Add warm water, or preheat the part, it will give you more fluid and accelerate reaction time. Even if you dilute it two times, but make it warmer by 20 deg C, it will be still faster. Essentially each 10 deg C double the reaction speed.
The insulation class simply tells you the maximum winding temperature, not whether it's designed for use with a VFD. Class F is 155C hot spot, Class H is 180C. You may also see Class B (130C). The main risk is bearing damage if you don't have a grounding arrangement for the rotor (effectively an electrically conductive brush). I'm sure it will be fine anyway. FWIW, my 1983 Shizuoka came with a Hitachi VFD from the factory (using IGBTs) - and a variable speed 3.5kW motor that was designed for use with a VFD.
@@RotarySMP Well I can help you with that, as I have the original invoice. I also managed to track down and speak to the original purchaser (I am only the second owner) and the guy who most likely built the control system at Matchmaker UK. The original cost was £38k and the sale was actually July 1984 (I was close!). Back then, that would have bought you a nice house. You'll be pleased to hear it did mostly aero parts before going into storage for over a decade when the guy retired. The VFD still worked but I couldn't reprogram it without the dedicated programming tool, so I had to scrap it. Last week we bought some SiC power modules - they cost something like £4k each. You pay top dollar for new technology....
I say keep the motor, use the VFD to power it through reasonable speed range and use the "variator" to select "virtual gears" with maybe 3 or 4 "speeds" and I would probably keep the backgear in the gearbox at 1:1, and switch it manually to low gear for some special job were you need more torque, but given the size of the machine I think it will be running fast most of the time. I would eliminate the posibility of the software somehow trying to shift into high or low gear while machine is running, that would stink. As for the switching of the motor windings- same, keep it simple and stick to high speed, maybe add contactors at a later date but like with the backgear, keep that system manual. Once the basics are up and running then start interfacing those systems into Lynux.
I like your summary. Basically what I was thinking. Primary speed control VFD, biasing with the Variator, and the back gear engaged only for large parts, slow speed. Back gear changing inhibited for CSS. I will have to try and implement that in logic.
Good plan I’d say. Definitely keep the motor - I’m running a few motors of that vintage on VFDs and haven’t killed one yet. No idea what insulation class they are.
Makes sense to keep the original motor. You already have an "inverter-duty motor" with the class F windings. From what I've heard and read, VFD voltage spikes are usually not a problem for 240V motors (480V and up are where you may have an issue).
@@RotarySMP Spitballing here, but since the topic of spikes from the VFD is worrisome, would 3 oil-filled (run type) capacitors of some value to be determined connected across each phase in delta configuration or 'Y' configuration help reduce stress on the motor windings? Also I remember reading the bearings can suffer due to stray electrical discharges when non-VFD rated motors are run on a VFD...again, would something as inexpensive as a capacitor (or 3) help aleviate this potential problem? I think some research on the topic needs to be done.
@@MRCNC1967 I asked my Electrical guru, as Schaublin had capacitors across the phases in the original installation. I understand that there are special filters designed for VFD usage, and that you cant use caps.
Yeah, that was supposed to just be my notes, and I figured none of it would show up in the video, once I overlaid it with video clips and photos, but oh well. I can read it (just).
Maybe add an AC line reactor between the motor and VFD. For just a little more impedence, they offer good harmonics dampening and a cooler running motor.
If you do set it up with both the VFD and the variator, you'll then be opening yourself up to a whole 'nother project around optimizing the efficiency curves. If this were my project at least, I'd be super tempted to do some dyno testing on the final lathe to get exact efficiency curves of each component, and set up the CNC controller to use some sort of numerical solver to command the most efficient combination of VFD and variator reductions for any given speed.
I have kept the 35 year 3-phase old motor and the set of pulleys on my small lathe and purchased a VFD so I do not have to change v-belt on pulleys that often. (AND I do not have to pay my electrical distributor to wire my garage for 3-phase) It hasn't even crossed my mind that VFD could damage my motor. I only run it up to 60Hz and I run 380V motor on a 3x230V (because I only have 1 phase at the garage and use 1-phase to 3-phase VFD. I have purchased used fancy VFD (altivar).
The more electrical knowledge you have, the more everything ruins everything else. I also used to think it was as easy as three wire, and you are good to go :)
@@RotarySMP Mind you, I am not electrician but I have consulted the vfd installation with experts at work and the motor wiring with a very highly qualified retired electrician - he also approved my plan to rewire my motor from star to triangle, so I can utilize the 3x230V vs original 3x380V more efficiently. None of experts mentioned that I have to have a special motor to run with vfd, I was just told not to try things like running it on 400Hz sinus, or changing the default switching frequency of the vfd to much higher values. I wanted to do that to mitigate the high-pitched whine typical for vfd-s. As I said, my vfd was purchased second-hand and it has obviously been installed in industry. I downloaded several hundred pages of wiring and programming manual - unlike cheap Chinese small vfd-s that come with 5 page manual (half of it in Chinese).
It might be a bit clunky having three different systems to change speed (VFD, Variator, Gearbox), especially when you are changing RPM to keep the surface speed the same when doing a face cut, but I would keep all three systems and figure it out in software. You never know when you are gonna need the extra torque of the variator and you can always run it as a fixed gearing.
Yeh, I need to think through the use cases. Other than the back gear being inhibited with the spindle running, I havent really got a goo plan for the control logic yet.
Keep the motor/cvt as it is, its beautiful and it works. You can't see such craftmanship very often today. Also remember the fact, that you dont have to put even one minute into it, while it still does its job fine with alotalotalotof torque, that you would throw away if you touch it. What would be the benefit of a replacement anywhere?
Maybe you can disassemble the motor, put the new varnish on the windings and put the stator in the oven. After that you can buy du/dt filter which should reduce the voltage spikes on the windings. In factory we always put du/dt filter when we use for example 4Q frequency converter. I should say that I was told by old engineers never to put VFD on the dahlander motor🧐 I think that this solution will cost more than the new motor. What about braking resistor? Will you have a problem with quickly slowing down and stopping.
I like the simple transmission+VFD combo idea. Complex mechanical systems usually have a bunch of custom parts, difficult to replace if needed. For the modern solution, it's much easier to find a compatible device (simple motor, VFD, belt pullies, etc.) and also to upgrade them one by one. On the other hand, without a large budget, keeping the present drivetrain makes sense. I think the main argument comes from the planned usage. Is it intended for hobby use only or business? What level of reliability and serviceability is targeted? (BTW the most advanced and compact solution would be a PMSM servo system. Oh, I'd love to see that! :)
I would keep the motor and the variator, then use the vfd and work from 30 to 50 hz this should be easier on the motor. Works like a charm on my old lathe
Great video! I just realized that there was no Annie while mentioning linux cnc, hope its not due to mine and some others ignorance, felt a bit sad, hope to see her in future one more time. And btw, "B Roll ideas: birds" ahahahaha
Run with the existing motor and variator, it's there, probably works, and it's cool. if it blows up, you've not lost much, and even then I'd be tempted to stick with the variator, you can't beat mechanical advantage!
Wow I did not know about these isolation calsses... I have to check for my VFD/motor setup 🤔 I would connect everything before installing _everything_ and make a test run. If it doesn't blow up right away then go ahead. I wonder if there are isolation testers for that?
There are insulation testers. Since the TWA 800 air distaster, insulation testing has become common with respec to fuel pumps and other fuel tank safety relevant components. Unfortunately, I have no access to one.
Maybe you can add an Filter to the Output of Your VFD. This would reduce the Voltage transients an so the Stress to the Isolation of the Motor., but this might increase the Capacitance to PE which might trip your RCD. ( I really like Filters with 3Phases + Neutral + PE instead of 3 Phases + PE )
I think that old motor will last longer than you think it will. But keep an eye out for a deal on a replacement just in case. Vinegar works great for removing mill scale but the smell is horrendous. I'm not sure what's worse vinegar or an open sewer pipe. What I do for painting stuff that isn't critical that it look perfect I just flush the spray gun out with thinner and call it done but the spray gun I use for that is a cheap $10 one from Harbor Freight which works surprisingly well for it's price. If it gets too gunked up I just toss it in the scrap pile and grab another. In the end it's cheaper than the chemicals to clean it properly every time.
This paint gun was also just a cheap import. Cant remember what I paid, but more than $10. Migh be time I replaced it though. I dont mind the smell of vinegar. I like the taste.
Most VFD can be set to 2 or 4 fixed frequencys,selected by 2 binary inputs, so you could wire the motor to the fast speed an emulate the slower with the VFD.
I'd keep the motor. I don't think it will die any time soon. I use a 1.5 kW motor with a vfd on my lathe. The motor still says made in czechoslovakia. Its insulation class E I think. So plenty old and not well insulated.
My understanding with VFD's is that running motor too slow that has a fan desingned to run at full speed wont have good enough cooling and that what kills motors that are not designed for VFD's We have two motors running from vfd, but they are only used for smooth start and stop so the motors dont heat too much
Keep the original motor, gearbox and CVT and just don't run it at crazy frequencies. Most of what I've heard on VFD's killing motors has to do with cheap import motors which were probably of questionable quality and would have died anyways, VFD or not. Additionally, the VFD you have appears to be of good quality so will likely have a cleaner output than a cheap import as well. Connecting some of the dots - higher insulation class means higher temperature resistance, and higher frequencies can lead to higher localised temperature. Put a thermocouple on the motor, keep an eye on it (or better yet have Linuxcnc keep an eye on it!) and be happy. Have the VFD drive the motor in its higher speed wiring configuration (2 pole?), I think that even half of ~550NM will be plenty for what you will throw at it when done.
The motor has some form of over temp relay, so I will feed that back into the E stop loop. Yeah, I will wire it for the 4 pole high speed (2 pole motors turn 3000 rpm, this is 1500). I need to think through the control logic whether to depend on the VFD for the primary speed control, of the CVT. the Back gear will have to be inhibited with the spindle turning.
Hey, this was a great flic. Finally some progress! Looks great. Didn't quite understand why the existing motor should burn out quickly, if it is insulation class F, or was that statement based on your assumption that it was not an F? Otherwise, very happy to see that you are making progress. The engine excursion was also very interesting. Thank you for that. Stupid question in this context. The large Turbofans of RR are based on the RB211 have not only 2 speed zones, but 3. So does that mean that these engines need substantially more engine maintenance ?
The motor is insulation class F, but it is also 40 years old. The RR three spool engines offer some of the theoretical advantages similar to a gearbox. At lest the core and intermediate can be smaller and turn faster. They are much lighter than two spool engines of similar thrust, but tend to have higher fuel consumption. All the big engines are very expensive once they hit the shop. It is hard to generalise which engines are more reliable, as each manufacturer has a family of models and is constantly trading reliablity earned through experience for incresed performance at each new model.
Variable drive looks well over engineered, Certainly very smooth in reducing induced vibration. I think VAG group (Volkswagen Audi), use a Hy-Vo chain, looks weird. For inverter duty, maybe worth a high voltage insulation test, I think WEG do a calculator based on motor size/class. I never knew there was a reduction gear between fan and compressor sections. Thanks for some very interesting engineering facets. Best regards from the Black Country UK
Thanks for the great explanations...I learn a lot from your videos. (Most I will not use but appreciate learning it anyway)...I got a shiver thinking about the low speed torque....One of the things I like about my little mini lathe is that the breaker kicks with very little load. This turns into a great safety factor for a novice for myself. Crashing the head doesn't break things AND if I were to get a body part in there it probably wouldn't amputate it. (don't want to find out though)....Considering using the motor or not: I would use it for now and if I found a need for that large of motor I would switch it to the need and get the new motor for the lathe.
Also for the mirror it turns out paint stripper will take off the plastic and then you can oxidize the copper to expose the silver. That gets you a delicate but ghost image-free inspection mirror.
Yeah, Them geared turbon fan planes are pretty cool. I've gotten to see drawings and how they test their new engine designs for their flight test beds as Pratt and Whitney do air tests with several types of planes. Though it sounds like they are retiring a few of them. Not sure why they don't break the fan into separate fans with them running at the same tip speed just a bit offset or if they had ring to keep them lined up. Even with a lower speed it should work, but how well is the question
An excellent video because it illustrated the range of things (jet engines) that I know nothing about but find facinating :-) It's always good to learn! In relation to the air pipes if the new tubing fits inside the old can you not use the old tubing as a sleeve over the new where the clamps are?
If its about vfd and 3f motor. I've heard the same myth as you said. Few years ago ive done some research, there will not be any problem with bearings due to its limits of rpm.(you can check yours) They are rated to much more than you could run your motor. BUT! theres problem with eddy current. It will heat up rotor and it axis which will damage bearings if you put too many hz through it. Btw. I run my mill and lathe with vfd, i am not guessing any of this :)
It will go in the building rubble. Plaster is basic, adding dilute acetic acid , they will neutralise to a few calcium compounds. Rust is not dangerous , except to bridges. This waste is not dangerous or toxic.
@@RotarySMP just busting your chops a little. You said "recycling" in the video, and I would assume the only kind of recycling available for this waste is the kind that involves plate tectonics and a few million years.
I agree with others, keep the motor and most of the mechanics, and figure how to drive it from CNC. Maybe use more modern contactors. It would nice to see this beauty work with all its mechanics. If that does not work, you can always scrap this idea, and do it other way later.
Your videos are always interesting - particularly with your tangents into aircraft. Now as for your lathe, if you have the potential to coldform wrought iron balustrades then why not keep it that way - jokes aside, cold forming processes may be an interesting adjunct for you - roll hardening, roll threading & roll burnishing on a small machine would be pretty cool & very handy. Good luck - Stay safe and well :)
Nice explanation od asynchronous jet motor :-) Very appriciate! I know you worked in aircraft industry, but what position? I really like jet engines and these information are so helpful. But to your Schaublin - although I love mechanical marvels, personaly i will use vector VFD instead of variator. #3 fan
air collet closer is awesome, it would also be cool is someone sent you a (Leader UK/Autogrip Taiwan) 4 inch auto/air chuck....probably the smallest in production
Hello Mark, I was not aware of the vinegar tip on mill scale removal, thank you. On the motor I would go with what you have and then replace in the future... Take care. Paul,,
600Nm is quite similar to my Okuma ACT4, according to charts I have, it has 670Nm in low gear, but with 30hp VFD motor, up to 1200rpm. High gear, 200Nm up to 3200rpm...
Would the VFD still give voltage spikes if it's only used to change the direction of the motor, rather than increase or decrease the speed? I suppose it depends on how smart the VFD's algorithm is or if there's a way of intentionally commanding it to do this, but in theory it should be possible to have it just connect the appropriate input and output phases without trying to switch anything.
I am pretty sure the way it chops up AC to DC and then rebuilds AC as a no longer smoothed sine wave is te same regardless of frequency, even if 50Hz in 50 out.
Calculate power and torque for cuts you expect. 600Nm cuts are........ unlikely. Back then, they were probably still considering tool steel cutter surface speeds.
Hey, i really like your Videos. i worked around 4 years with Schaublin 125 and CCN125 and the one Problem i had, quite a lot was that the variable Beltdrive couldnt transfer all off the Torque form the Motor. My take on that would be to change the lower beltdrive to a toothed belt and keep the gearbox as is.
Wow, that is an interesting input. What were you turning that needed such high torque? I find it surprising that this little lathe even needs so much torque capablity.
@@RotarySMP well we did quite a lot of stainless on them. That Problem occurred mostly when we did Threads like M12-M16 with a tap. When the variator is on the lower end of the RPM range the Belt tension is going down a bit and therefore the transferable force decreases. Maybe it is possible to adjust the mechanic but i didnt had the time to really dig in to that. And like you mentioned, it would probably be easier to eliminate the variator and just keep a 2-way mechanical gear than to implement the variator on the Software. Regardless of that, it is a fine piece of Engineering and i liked working with the variator a lot.
I have an avm mas165s cnc lathe that I converterted to pathpilot. It has a 2.2kw (3hp) spindle motor driving a 2 speed gearbox in the head giving rpms of 50 to 1500 and 150 to 4500. In my case 3hp is fine but I could easily go bigger. I'd keep with the 3kw motor if I was you. At least until you have it running then you can up the hp if you find it struggling
@@RotarySMP thanks, it's not a bad machine. It was originally fitted with a fanuc 3t control and a 7.5kw (10hp) spindle motor. However I got the machine without any of the electronics. So I decided to go solely single phase. Using a mesa 7i92, custom breakout board with arduino ( to control the turret), Chinese 750w ac servos and a standard 2.2kw 3 phase motor for the spindle driven by a vfd.
Me too. I always hated having insufficient torque on the Mini lathe. Drove me nuts to have to turn to fast, burning up cutting edges, and chattering, because the low down torque was missing.
Fascinating stuff thank you for posting. But why do you pronounce Linux as "Lyn Ox" when everyone else I've ever heard say it, says "Lyn Ucks", including several Kiwis I know? ;-)
I would leave the motor and drive as is. Seems beefy and well designed. On a side issue, is it true that cable length between a motor and vfd affect the motors life/insulation? From what I remember very short cables really help the motor. Any ideas on that?
Maybe it is because shorter (or thicker) cables have lower resistance which may keep the voltage spikes on a lower level. In any case, short and thick cables are always the right choice for good performance... It should also be possible to reduce the voltage spikes with capacitors, but you need to find out which ones are the right ones, otherwise they may get hot or the may damage the VFD.
I know shorter and shielded cables are preferred, but I remember powder coating line with VFDs on one side and conveyor motors on other side, about 50 meters of shielded cable. Worked like a charm for 20+ years.
@@RotarySMP Great to hear you are just normal lazy person :) Also I guess most of cable is hidden within Schaublin's metal frame, so it's already shielded good enough!
You can try some citric (lemon) acid for scale/rust removal. It work same way as vinegar, but it smell much nicer :) And... you can adjust concentration as you wish. Not sure for Germany, here you can bye it at any grocery store.
@@RotarySMP recycle it on the fush & chups :) I wonder how many recognized the SHMBO reference? I'm guessing SHMBO would not, which is fortunate for you
Thanks for the tips about the vinegar & mill scale. I just bought several sheets of steel just like you are using, for a future project after I finish my plasma table. Now I know how to treat the steel for painting. Is there a way to remove dark stains on metal? I got some moisture in my shop while working on the cast iron ways on my mill and ended up with dark patches in various places. Nothing to cause any problems but they look unsightly and it would be nice to make them go away. Looking forward to seeing the wheels go round on the Schaublin. Thanks for all you do.
I‘d replace meanwhile i dunno where you could even get that chunker off a motor. A direct spindle would be even nicer but these are unobtainium + price.
Keep the variable drive but put a hand crank on it. Thank you for the analysis of the geared fan; I'd sure like to see the condition monitoring regime for that gearbox.
With the set up of VFD + CVT + Backgear, I am pretty sure I dont need a hand crank :) Good point. But other than monitoring vibes, oil temp and Px, soap sampling the oil there wont be much they can do. Another commented that they have some boroscope inspections already but with tiny 2mm light guides, it is a real PITA.
@@jimsvideos7201 For me that may be increased complexity, as I already have the CVT motor, wiring, and control board. It just takes a couple of output pins from a Mesa card to give LinuxCNC control of it. The hard part will be writting the control heirarchy of when LinuxCNC should change VFD vCVT v Back gear.
@@RotarySMP yes, it potentially gets around the fan size limits etc. And allow distribution of thrust and possible hybrid aircraft etc. Sounds interesting 8-)
@@wktodd I guess it depends on the losses in the round trip from shaft HP to angry electrons, and back to shaft HP. I cant see it happening for large turbofans, as there is so much beyond efficiency, such as debris trajectories, fire protection etc which would make it very hard to find an airframer willing to do anything radical.
i use a poly v belt instead of the variator. the motor i use is a 2.2kw motor with 1500rpm. i use a 5kw VFD so i'm able to clamp the motor in delta. so i can use the full torque at lower speed and i have 3.3kw at 87Hz. the motor runs at higher speed in field weakening operation to 120Hz with no problems. the use of the 1:6.5 oettinger is a must, but the variator isn't necessary if you use an VFD. if you'd like to give it a try, come over to my 125 ,-)
Good points. Since it is easy enough to pull the motor, I figured I'd leave the variator as is for now, and can still replace it later with a poly-Vee once I get the machine running. You added an exra fan to cool your motor right?
@@fuzzy1dk Yes. Fixed pitch props are really only used on ligt aircraft. GE had a test program called the UDF (Un ducted fan) in the 90's which had variable pitch blades, unshrouded, and driven off the LPT. Kind of a mash up of turbofan and turboprop tech. Great fuel efficiency, but i think noise killed it.
What would I do? Well I know what I wouldn't do - try and grab the chuck with my hand when it's in low speed and back gear! :D Keep the CVT. A quick search - ie based on no personal experience whatsoever - suggests high frequency components from the VFD can lead to large induced currents in motor shaft which if passed through bearings can shortens their life? That said, absolutely nothing on that Schaublin seems marginally engineered. PS. is the name plate clean enough yet?
Thanks. This lathe spindle will not stop for anything. Definitely not a machine to crash. I was looking for a brush to clean the nameplate, and then forgot.
I'm pretty sure original motor will survive. I honestly never heard of output filter for VFDs which people mention in comments, I know only of input filters. If you plan to run it on lower speed, you might consider replacing motor's fan blades with external fan. You can buy motors like that (I think Lenze actually makes those), practically normal motor with longer body and fan slapped on end, independent of motor shaft. When VFD is driving motor at any speed, it automatically switches contactor and runs this fan on motor at full speed. Also connection between motor and VFD is usually done by shielded cable. Shorter is better, but I've seen even huge motors 50 meters away from VFD and it worked for 20+ years with no issue. About transmission, I think you should really keep everything like it is, even if it wasn't used now. For first experiments you can change speed just by VFD and control variator manually, later you can fine tune control of all those transmissions in software. Three "transmissions" in series aren't usual and it might be really interesting to see everything working at once. And you can make TOT jealous of such high numbers :P Maybe it might be good idea to add some potentiometer on variator (if there isn't one) so you can guess at which gear ratio you are right now? And one last thing, make sure you understand all parameters in VFD before turning on motor. It usually wants not only nameplate frequency, current and voltage of motor but sometimes other things too. Also there are questions like what will happen when motor is overloaded? Some VFDs can try to keep set speed, some rapidly slow down to last speed which fits set maximum current. And so on, it would be shame to overlook some important settings in manual ;)
Thanks for the suggestions. Really appreciate that. The power cable is the length of the bed. Wont get it short than that, but it is only about 2m. I was also thinking about starting with the back gear and VFD under LinuxCNC control, as there are already software components for that. I could just bias the Variator with push buttons. The problem with that is a temporary solution which works is permanent. I need to have a think about the logic to control these three. Putting some feedback of Variator position is a good idea. I hadn't thought of that. Luckily I got the Lenze VFD with a programming module and instruction manual,but thanks for the reminder, as I set up my Siemens VFD just as you recommended, first inputting all motor parameters before hook up.
@@RotarySMP You're welcome, I hope my comments won't disappear after sending like on different video some time ago. Actually I tried to post one comment yesterday like three times on different channel and it just wasn't working. Comment is here, refresh, comment is gone :/ Then it should be fine. And in worst case you can wind some aluminium foil around, if there were some problems with interference. But I guess cable will go inside of metal frame, so it's actually shielded good enough :) Oh come on, it can't be that bad! :D On other side I'm even worse for sure. I'm dreaming for 10 years about building of hobby CNC and all I have are ideas and maybe some really old 3D sketch. I'm changing topology of everything in my head practically every month and it became one of "I'm bored, let's dream about CNC" things. How to make it cheap, simple and robust...and idiotproof, so even I can drill holes (I can't drill three holes in straight line x.x ) and somehow align that whole mess. That reminds me, how is transmission ratio for that backgear? Originally I wanted to suggest simple deciding function but I got totally lost on how that backgear works. It's just switching in between of two ratios, right? I thought it might help program to at least know where it is and which way to move, also with some calculations it means one more "speedometer" on your LinuxCNC screen :) I'm keeping my fingers crossed for you. I was setting up only small Yaskawa V1000 drives and old Omron drive at work and I got really surprised how many things it can do. For example that Yaskawa does have even PID regulator for speed control, crazy! Maybe you'll find something really awesome too. Or at least you will be sure why are some things happening, which can help with troubleshooting later.
@@DreitTheDarkDragon Yep, the back gear uses a pneumatic piston to select between 1:1 and 6.5:1 ratios. Putting feedback on the Variator was already suggested. It is a good idea. Wonder if there is any simple way to get feedback of the back gear position?
@@RotarySMP Hmm, I'll have to check your videos again to see how it is done mechanically. If it was standard pneumatic cylinder, you could use magnetic sensors, since pistons in industrial cylinders are usually (not always) magnetic and there are grooves for sensors prepared. Other way are induction sensors (M12 or M8 size are common, sensor itself is fine threaded rod with LED and connector), sensing presence of metal. For example you can have two sensors and then metal ring fixed on shaft which slides back and forth in front of sensors. Usual sensing distance is about 4 mm for M12, smaller case (M5, M8) usually means much shorter sensing distance. Induction sensors are also often used to measure speed of shafts (just screw something on shaft to make pulse every revolution). I was in USA recently and I noticed there are even induction sensors for high pressures, connected directly on hydraulic circuit. I took only photo of sensors itself, but it seemed to be going thru T-piece and sensing piston itself, while pressurized oil flows around sensor ._. Really interesting solution. And if even that can't be used, I heard of solution which measures air pressure during movement. Not air amount (those must be pretty expensive) but only pressure. Problem is when piston gets stuck, you can't simply detect that. Maybe with good timing you might pressurize cylinder (it should move to end position), then release pressure and measure how long it takes before pressure in cylinder falls - further movement means more air and more time. If time fits expectations, you can pressure it again to hold it in that position. But I've never seen this in real life, only heard it's used somewhere, I'd take that as last resort. I'm not even quite sure if it works how I think it should. I'm personally huge fan of induction sensors. It's nice to have magnetic sensors on body of pneumatic cylinder, but it can't tell cylinder separates from object it was moving. PLC is happy to see piston in correct position but part which it was pushing/pulling might be somewhere else.
Motorscooters use this type of Variomatic with a rubber belt. But the gear ratio is changed via flyweights, so it changes automatically with the engine rpm. That may be a perfect combination with VFD to maximize the torque at low speeds...
I'd hope to keep the original stuff, it's already there and has worked 40 years already, why not another 40?
Yeah, I like it as well. If I set up VFD + CVT + backgear, I could near continuous speed from 3000 done to about 10 RPM, with more grunt than a rutting sperm whale.
@@RotarySMP You owe me a cup of tea and some bandages from the scalding - LOL
@@phrozenwun Glad you liked it :)
I definitely second this. It's an old machine. If you can get it working on the software side then keep the variator and gearbox. Electromechanics are cool and servo drives are boring. :)
@@Joelsfilmer Good call.
I liked the explanation of issues P&W faces with its new design a lot. It is so true: what is not on an engine can't break.
When I was researching this, I was really surprised that the PW110G is not significantly lighter than the Leap-1A. One of the benefits of the high RPM core and LP should be a much lighter engine. Will be interesting to see if that gearbox pays off for them.
@@RotarySMP Increased fan diameter means bigger diameter fan shroud, which not only is getting heavier because of size, but also needs to contain blade-outs of the fan blades, that are also getting bigger and heavier. There is a practical limit to increasing the bypass ratio mostly dictated by the structural weight. This is why engine manufacturers are looking into unducted fans and propfans again in recent years.
If engine builders were thinking like that, we would still be using turbojets with horrible fuel economy. Progress brings complexity, it's unavoidable.
@@stefanpariyski3709 I just find it fascinating that GE can keep ahead of both Rolls 3 spool designs and Pratt's GTF with a very conventional 2 spool designs. GE has invested heavily in process tech like CMC's and metalic additive manufacturing
I say keep it. It's going to make the wife happy, and if it actually dies you can justify a new motor much more easily. And software control should also not be a huge problem, depending on how LinuxCNC manages that.
Also, that bit about the turbines was really interesting, I hope you keep those segments coming!
Thanks for the feedback. The challenge for me will be working out how to schedule the overlapping control loops of VFD, Variator, and back gear.
Drivin' Miss Lathey. Cool.....and a great discussion about Turbines. Thanks.
THanks Anton.
Thanks for the crash course on jet engines - was an interesting new look at them. I would keep the old motor and related hardware until it no longer goes - it may still surprise you :-)
Thanks for you feedback. I hope for that surprise too.
This is the best linux cnc conversion series ever, lathe my mind
Thanks for the kind words.
Keep the motor if it works, it's the heart of the machine.
WIll do. Hope it survives the VFD.
Perfectly complete episode….. vinegar baths, turbine engine development, 3ph motor/drivetrain graphs, cleaning the workbench…… it’s got it all. Since you asked for votes, I would start skipping one latte every week at Starbucks and deposit that money in a new motor piggy bank, and drive on. If the motor bearings are good and your not planning to put this lathe into 24/7 production mode, this original motor will likely outlast you and your heirs will inherit a nice bonus account.
Questions - Was that apple cider vinegar? How eye-wateringly fragrant does the workshop get after 48th hours of evaporating vinegar? Does that vinegar air tend to rust other metal nearby? Maybe you covered the pool with another bag? Would 5 of the smallest standoffs (like M3 nuts), one at each corner and one in the middle, be sufficient to etch both sides at once without needing much more volume?
That was cheap and nasty supermarket own brand vineagar. 60c a litre. The Ions in the air dont rust everything as badly as the time I did fast mill scale removal with HCl, and split a bunch on the floor.
m3 nut is too flat, the bag would touch the steel , but even if it would be enough, 1mm thickness @ 1 square meter area is 1 litre of volume.. so even prepping up with m3 nuts would consume the 1l bottle of vinegar without having enough vinegar on top.
@@robertjung8929 If I had put paper towels on top, it probably would have keep it moist, avoiding the pitting. Not like it really matters. It is only for screwing the electic to.
I was a GSE/AGE mechanic in the USAF. Your explanation of a GTC and the design changes/differences was a thing of beauty. I worked with a power unit we called a -60 it had 3 phase 120 VAC 400hz power. It had a two stage compressor and a single turbine wheel.
Thanks for the feedback. Gas turbine ground power. perfect to run the home shop :)
The amount of fuel to run a GTC generator would be enormous. Not fuel efficient but very smooth running
@@JMassengill Yeah they drink gas. Especially in start up.
very good job RotarySMP
Thanks for the feedback as ever.
This was a great episode, thank you. I learned the vinegar/mill scale trick from one of your earlier videos and have used it a few times - great tip. I loved the tangent talk on jet engines too, so thanks for that. My vote for the motor is defo try and use the existing power train. Really only because that's what I would do, not because I have special knowledge/experience. I don't mind if you ignore this and go for a new motor, I'm just one of the Heathers that enjoys your channel. Good luck with whatever option you go with.
- Heather
Thnks for the kind feedback Heather.
I bought an old wood lathe at an estate sale. Thought I got good deal. The guy said it just needed a pulley. I didn't know much back then and know less now, so I bought it. Turns out I needed a special pulley that I had never heard of before. A reeves pulley was my introduction to variable speed pulleys. Well. I never have found a replacement for that pulley. I 3D printed one that fit the shaft. I fell apart when I tried it out. Live and learn. That's wild about the motor to run the variable pulley width. Cools stuff. Thanks for the lesson. And this lesson is modern time in a nutshell. Software may have eaten the world, but hardware had a great appetizer!
I like that statement. Hardware is cool.
My lathe had a similar system. I use my every day and it is very important for the company. So I decided to make it simple. Took the variator off, and the back gear. Made a pulley reduction. And used a high speed and considerable more powerful motor with a VFD.
But if it was a machine for casual use. I probably would had kept all original like you did on the maho.
Thanks for the feedback. It would take a pretty huge motor to replace the back gear, and I only have a 16A home electrical supply.
@@RotarySMP True but keep in mind that high frequency motors develop more power with the same size motor.
I love the aviation interludes my late father was a avionics engineer on RADAR - lightnings, buccaneers and lastly sea harriers so I grew up with aircraft and his explanations on how things worked.
That is some cool stuff he worked on.
That's a interesting side bar about the turbo fan. And I agree with your comment on not having anything to break, I always say, "there's nothing to go wrong when there's nothing to go wrong."
Pratt have tried this before (PW8000). I heard that was their gearbox design, and ended up not commercialised. That is where I heard that MTU designed the PW1000 gearbox. If they can make that work, it should really squeeze the competition.
While the motor was out I would considered removing the gearbox and pulley system but I would have opted for least amount of work and reinstalled everything just like you did, kicking the can down the road.
Thanks for the vinegar explanation.
Thanks for the feedback. Hard to beat that which is already there.
@@RotarySMP I was thinking...
You mentioned 5 x contactors. Have you considered a manual two position lots of poles industrial switch to change the motor between start & delta?
Lots of good progress this week. I hope the motor lives on.
Thanks for the feedbacl. I hope so as well.
For mill scale removal I use those purple and spongy "cleaning discs" for angle grinders. They are fast, cheap, don't bite into the base metal, and don't clog up like flap disks do. Nice video, really appreciate the info on turbines! :D
I also use discs on small parts, but that had a lot of surface area, and it would have been a PITA to grind it all off.
Thanks for the feedback.
I'd personally persevere with the existing setup as without it you loose some of that gorgeous overengneered Swiss watch feeling it has.
Good point. It is pretty amazing what they consider adequate iron for a simple bracket.
I replaced the motor on my lathe with a mining spec abb 1hp motor, not even sure what the insulation class is but it's been running fine on an import VFD. IP65 rated, I can hose it down if it gets warm 😜
I like that :)
Loved the airplane engine discussion.
Thanks for the feedback.
Wow what a great episode!! For what its worth ive been running a Colchester Student lathe with its original 3 phase motor 2.2 Kw for approx 20 years with an SEW eurodrive VFD. Single to three phase setup.haven't killed it yet, but only a small amount of weekend warior work. The lathe was ex Wellington polytec.
Only having one fifth of the torque at low speed means you might have to take a smaller deepth of cut, but more importantly the cutting speed will be corect. Unless your putting this thing into production of large diameter parts and time is critcal.
Thanks for the data point. My local electrical hero wants me to run a double shielded cable from the VFD to the motor though.
My setup is only manual lathe so no issues with noise. There is no shielding on the cable, but the VFD does make the radio Fuss a little. With a plug swap system for power and control this VFD also runs an old Bridgeport mill(1.5 horsepower original motor) It has also lived a long time. I also had to convert the motors from star to delta or vice versa, i cant remember 20 years ago.
Thanks for the jet engine lecture! I learned a whole lot of new stuff!
Thanks for the feedback.
if you want to learn too much about jet engines, go visit Agentjayz, ua-cam.com/users/AgentJayZ
@@fuzzy1dk Thanks for the link.
Personally, if it were for me, I'd keep the belt drive and install a few contactors. Linux CNC can handle them easily, no buggering about with variators, you get continuous speed variation with no electrical noise, and enormous torque. Not to mention that replacing a belt is far cheaper than replacing a VFD.
How would you get continuous variable speed with only contactors? No variator and no VFD?
@@RotarySMP Ah, my bad wording. Keep the belt drive *variator*, and drive the electrics how they were originally designed. New contactors driven by whatever voltage your linuxcnc board can drive (and is already driving elsewhere), obvs. No buggering about VFDs (in my defence, "variator" is what they're called over here in frogland)... It's a very robust solution.
@@wibblywobblyidiotvision I'll second this idea.
Note that this lathe has somewhat the opposite condition of the P&W engine: it and countless other machines have run just fine with a variable belt drive for decades, and the VFD is the unproven technology.
Even better would be to in place of contactors to use IGBT transistors, they will be quieter, smaller and easier to drive.
@@lwilton VFDs are hardly unproven. There are millions of them running around the world and have done so for decades. Not as long as variable belt drives but there are millions or billions of hours of accumulated operation.
I like the mechanical speed variator! Especially since it can be controlled through CNC. My mill at work I use is a CNC conversion type knee mill and it doesn't have a CNC controlled variator but otherwise I really like the variator! Unless its a safety hazard I would leave the original motor for as long as possible and just replace that with a VFD compatible one while leaving the mechanical variator if the old motor dies.
Thanks. That is the plan.
Love it! I flew the Pratt F100's and GE110's in the Air Force. Also, I flew the JT8 series in the airlines. GREAT ENGINES. Our Airbus fleet has the IAE engines. I didn't get to fly them with CFM engines. Keep up the great work......
I thought you might like that one. :)
V2500 - bastard son of strange bed fellows... as is the GP7000.
@@RotarySMP LOL! Yup.....
I have an similar age 3kW manual lathe that I'm running on a VFD and it hasn't killed the motor yet. With the caveat that I don't know if it's the original motor but it probably is, there was only one prior owner of the lathe and they didn't use it much.
Thanks. That is a good data point. It seems Schaublin generally bought high end hardware for this machine, so hoefully that goes for that motor as well.
@@RotarySMP Here's another (not very close) one: I worked with an Italian packaging machine for a while. Similar age, similar motor size, different mechanical load. The motor died from the VFD while I was there. It was used for many years with that though. It functionally replaced the manually adjusted CVT after a large, custom spring broke in it multiple times.
@@besenyeim Thanks for that info.
Another great video!
THanks for the feedback.
Perfect sunday „morning“ 😁
Thanks for the feedback.
I can't wait to see the first parts that come off this thing! - Love the aircraft stories and notes!
Thanks for the feedback.
Rolls Royce is building Ultrafan which should have a gearbox too. Also composite fan blades for weight reduction as compared to titanium ones. The bigger engine you make the bigger the centrifugal forces you need to deal with. Fun fact Tupolev Tu-95 tips of the blades are turning faster than speed of sound making it apparently very loud plane
RR tried composite blades first. The development was part of what pushed them into receiver ship in the1970's. It took GE also about a decade of research to perfect the composite blades used on all their large turbofans since the GE90. There are a number of advantages, including that the tend to pulverise in a blade out event making containment easier.
I heard an AN-22 on approach to Vienna about a decade ago. They have the same NK-12's as the bear. It is a very distinct sound, unlike any other plane, and that was only at approach power. Interesting fact, is that the NK-12 was designed by an Austrian, Ferdinand Brantner, who was a Junkers design engineer deported to the Soviet Union after the war.
I would replace the drive line with a new bigger motor and only an vfd/backgear.
Thank you for the nice video's , i enjoy watching them !
Thanks for the feedback. That is my second choice, if the existing part I already have fail.
With proper output filtering you can get rid of the Output spikes from the VFD. Some just use a shit load of "ferrite" or better noncrystalline Toroids in CMC configuration.
There are "proper" Filter modules commercially available but they are not cheap.
Common mode Cokes are also necessary to protect your motors bearings.
Thanks for that. I'll google to find out what all those are :)
keep the motor and run it until death do you part. btw i do like your 20min video format much better than the shorter ones, while more compressed content. keep up the good work. Greetings from a former aircraft mechanic
Thanks for the feedback. I first thought this one was too long, but ran out of time and ides to edit it tighter.
@@RotarySMP you cannot put as much content in 10min or less, thats why 20min is ideal for explaining and going into detail
For the vineger. Add warm water, or preheat the part, it will give you more fluid and accelerate reaction time. Even if you dilute it two times, but make it warmer by 20 deg C, it will be still faster. Essentially each 10 deg C double the reaction speed.
Thanks for the tip. Given my basement is currently at about 15°C, I just let it soak over night. No hurry. Just should have used a little more.
The insulation class simply tells you the maximum winding temperature, not whether it's designed for use with a VFD. Class F is 155C hot spot, Class H is 180C. You may also see Class B (130C). The main risk is bearing damage if you don't have a grounding arrangement for the rotor (effectively an electrically conductive brush). I'm sure it will be fine anyway.
FWIW, my 1983 Shizuoka came with a Hitachi VFD from the factory (using IGBTs) - and a variable speed 3.5kW motor that was designed for use with a VFD.
I hate to think what that quipment cost new.
@@RotarySMP Well I can help you with that, as I have the original invoice. I also managed to track down and speak to the original purchaser (I am only the second owner) and the guy who most likely built the control system at Matchmaker UK.
The original cost was £38k and the sale was actually July 1984 (I was close!). Back then, that would have bought you a nice house. You'll be pleased to hear it did mostly aero parts before going into storage for over a decade when the guy retired.
The VFD still worked but I couldn't reprogram it without the dedicated programming tool, so I had to scrap it.
Last week we bought some SiC power modules - they cost something like £4k each. You pay top dollar for new technology....
I say keep the motor, use the VFD to power it through reasonable speed range and use the "variator" to select "virtual gears" with maybe 3 or 4 "speeds" and I would probably keep the backgear in the gearbox at 1:1, and switch it manually to low gear for some special job were you need more torque, but given the size of the machine I think it will be running fast most of the time. I would eliminate the posibility of the software somehow trying to shift into high or low gear while machine is running, that would stink. As for the switching of the motor windings- same, keep it simple and stick to high speed, maybe add contactors at a later date but like with the backgear, keep that system manual. Once the basics are up and running then start interfacing those systems into Lynux.
I like your summary. Basically what I was thinking. Primary speed control VFD, biasing with the Variator, and the back gear engaged only for large parts, slow speed. Back gear changing inhibited for CSS. I will have to try and implement that in logic.
Good plan I’d say.
Definitely keep the motor -
I’m running a few motors of that vintage on VFDs and haven’t killed one yet. No idea what insulation class they are.
Very interesting stuff about those jet engines!
Sure are. Fascinating how much research goes into ever aspect.
Makes sense to keep the original motor. You already have an "inverter-duty motor" with the class F windings. From what I've heard and read, VFD voltage spikes are usually not a problem for 240V motors (480V and up are where you may have an issue).
3Ph here is 380V. 240V per phase. I hope you are right and the motor survives.
@@RotarySMP Spitballing here, but since the topic of spikes from the VFD is worrisome, would 3 oil-filled (run type) capacitors of some value to be determined connected across each phase in delta configuration or 'Y' configuration help reduce stress on the motor windings? Also I remember reading the bearings can suffer due to stray electrical discharges when non-VFD rated motors are run on a VFD...again, would something as inexpensive as a capacitor (or 3) help aleviate this potential problem? I think some research on the topic needs to be done.
@@MRCNC1967 I asked my Electrical guru, as Schaublin had capacitors across the phases in the original installation. I understand that there are special filters designed for VFD usage, and that you cant use caps.
I like that your clever plane eng notebook looks like my site diary😀. And I think my handwriting is slightly better! Cheers man.
Yeah, that was supposed to just be my notes, and I figured none of it would show up in the video, once I overlaid it with video clips and photos, but oh well. I can read it (just).
Maybe add an AC line reactor between the motor and VFD. For just a little more impedence, they offer good harmonics dampening and a cooler running motor.
Thanks for the tip.
If you do set it up with both the VFD and the variator, you'll then be opening yourself up to a whole 'nother project around optimizing the efficiency curves. If this were my project at least, I'd be super tempted to do some dyno testing on the final lathe to get exact efficiency curves of each component, and set up the CNC controller to use some sort of numerical solver to command the most efficient combination of VFD and variator reductions for any given speed.
Yep, I really dont have a clear idea of the pros V cons of making the CFD primary, or the CVT primary spped control.
I have kept the 35 year 3-phase old motor and the set of pulleys on my small lathe and purchased a VFD so I do not have to change v-belt on pulleys that often. (AND I do not have to pay my electrical distributor to wire my garage for 3-phase)
It hasn't even crossed my mind that VFD could damage my motor. I only run it up to 60Hz and I run 380V motor on a 3x230V (because I only have 1 phase at the garage and use 1-phase to 3-phase VFD. I have purchased used fancy VFD (altivar).
The more electrical knowledge you have, the more everything ruins everything else. I also used to think it was as easy as three wire, and you are good to go :)
@@RotarySMP Mind you, I am not electrician but I have consulted the vfd installation with experts at work and the motor wiring with a very highly qualified retired electrician - he also approved my plan to rewire my motor from star to triangle, so I can utilize the 3x230V vs original 3x380V more efficiently. None of experts mentioned that I have to have a special motor to run with vfd, I was just told not to try things like running it on 400Hz sinus, or changing the default switching frequency of the vfd to much higher values. I wanted to do that to mitigate the high-pitched whine typical for vfd-s. As I said, my vfd was purchased second-hand and it has obviously been installed in industry. I downloaded several hundred pages of wiring and programming manual - unlike cheap Chinese small vfd-s that come with 5 page manual (half of it in Chinese).
@@first_namelast_name4923 This Lenze also has a very good and thorough manual.
It might be a bit clunky having three different systems to change speed (VFD, Variator, Gearbox), especially when you are changing RPM to keep the surface speed the same when doing a face cut, but I would keep all three systems and figure it out in software. You never know when you are gonna need the extra torque of the variator and you can always run it as a fixed gearing.
Yeh, I need to think through the use cases. Other than the back gear being inhibited with the spindle running, I havent really got a goo plan for the control logic yet.
Keep the motor/cvt as it is, its beautiful and it works. You can't see such craftmanship very often today. Also remember the fact, that you dont have to put even one minute into it, while it still does its job fine with alotalotalotof torque, that you would throw away if you touch it. What would be the benefit of a replacement anywhere?
Yep, you summarised my thoughts well there. I already own it, and it works.
Maybe you can disassemble the motor, put the new varnish on the windings and put the stator in the oven.
After that you can buy du/dt filter which should reduce the voltage spikes on the windings. In factory we always put du/dt filter when we use for example 4Q frequency converter.
I should say that I was told by old engineers never to put VFD on the dahlander motor🧐
I think that this solution will cost more than the new motor.
What about braking resistor? Will you have a problem with quickly slowing down and stopping.
Thanks for the feedback on that.
I like the simple transmission+VFD combo idea. Complex mechanical systems usually have a bunch of custom parts, difficult to replace if needed. For the modern solution, it's much easier to find a compatible device (simple motor, VFD, belt pullies, etc.) and also to upgrade them one by one.
On the other hand, without a large budget, keeping the present drivetrain makes sense.
I think the main argument comes from the planned usage. Is it intended for hobby use only or business? What level of reliability and serviceability is targeted?
(BTW the most advanced and compact solution would be a PMSM servo system. Oh, I'd love to see that! :)
This is definitely a hobby system, which is unlikely to see anything like industrial usage.
I would keep the motor and the variator, then use the vfd and work from 30 to 50 hz this should be easier on the motor. Works like a charm on my old lathe
That is about what I will do.
Great video! I just realized that there was no Annie while mentioning linux cnc, hope its not due to mine and some others ignorance, felt a bit sad, hope to see her in future one more time. And btw, "B Roll ideas: birds" ahahahaha
I knew someone would notice that :)
Run with the existing motor and variator, it's there, probably works, and it's cool. if it blows up, you've not lost much, and even then I'd be tempted to stick with the variator, you can't beat mechanical advantage!
Thanks. If the existing motor dies, the Variator will have to come off, as it needs an extended shaft motor.
if you are concerned about the vfd killing the motor, consider a sine wave filter between vfd and motor
Thanks. Good idea.
Wow I did not know about these isolation calsses... I have to check for my VFD/motor setup 🤔
I would connect everything before installing _everything_ and make a test run. If it doesn't blow up right away then go ahead.
I wonder if there are isolation testers for that?
There are insulation testers. Since the TWA 800 air distaster, insulation testing has become common with respec to fuel pumps and other fuel tank safety relevant components. Unfortunately, I have no access to one.
Maybe you can add an Filter to the Output of Your VFD. This would reduce the Voltage transients an so the Stress to the Isolation of the Motor., but this might increase the Capacitance to PE which might trip your RCD. ( I really like Filters with 3Phases + Neutral + PE instead of 3 Phases + PE )
Thanks for the tip.
Not replace. The Reeves drive is a sound way to create tons of torque. KISS
Cheers
Yep, hope the motor holds up.
I think that old motor will last longer than you think it will. But keep an eye out for a deal on a replacement just in case. Vinegar works great for removing mill scale but the smell is horrendous. I'm not sure what's worse vinegar or an open sewer pipe.
What I do for painting stuff that isn't critical that it look perfect I just flush the spray gun out with thinner and call it done but the spray gun I use for that is a cheap $10 one from Harbor Freight which works surprisingly well for it's price. If it gets too gunked up I just toss it in the scrap pile and grab another. In the end it's cheaper than the chemicals to clean it properly every time.
This paint gun was also just a cheap import. Cant remember what I paid, but more than $10. Migh be time I replaced it though.
I dont mind the smell of vinegar. I like the taste.
Most VFD can be set to 2 or 4 fixed frequencys,selected by 2 binary inputs, so you could wire the motor to the fast speed an emulate the slower with the VFD.
The Mesa 7i83 has analog outputs, so I will be setting up the VFD to be controlled with a stepless speed range from LinuxCNC.
I'd keep the motor. I don't think it will die any time soon. I use a 1.5 kW motor with a vfd on my lathe. The motor still says made in czechoslovakia. Its insulation class E I think. So plenty old and not well insulated.
I did not try the original 1940s Motor with fabric insulation tough....
Thanks, I like to hear data points like that. Hope that motor is listening :)
My understanding with VFD's is that running motor too slow that has a fan desingned to run at full speed wont have good enough cooling and that what kills motors that are not designed for VFD's
We have two motors running from vfd, but they are only used for smooth start and stop so the motors dont heat too much
That is why I am setting a pretty high minimum speed of 20Hz. so that the fan keeps air moving.
Keep the original motor, gearbox and CVT and just don't run it at crazy frequencies. Most of what I've heard on VFD's killing motors has to do with cheap import motors which were probably of questionable quality and would have died anyways, VFD or not. Additionally, the VFD you have appears to be of good quality so will likely have a cleaner output than a cheap import as well.
Connecting some of the dots - higher insulation class means higher temperature resistance, and higher frequencies can lead to higher localised temperature. Put a thermocouple on the motor, keep an eye on it (or better yet have Linuxcnc keep an eye on it!) and be happy.
Have the VFD drive the motor in its higher speed wiring configuration (2 pole?), I think that even half of ~550NM will be plenty for what you will throw at it when done.
The motor has some form of over temp relay, so I will feed that back into the E stop loop. Yeah, I will wire it for the 4 pole high speed (2 pole motors turn 3000 rpm, this is 1500). I need to think through the control logic whether to depend on the VFD for the primary speed control, of the CVT. the Back gear will have to be inhibited with the spindle turning.
Hey, this was a great flic. Finally some progress! Looks great. Didn't quite understand why the existing motor should burn out quickly, if it is insulation class F, or was that statement based on your assumption that it was not an F? Otherwise, very happy to see that you are making progress.
The engine excursion was also very interesting. Thank you for that.
Stupid question in this context. The large Turbofans of RR are based on the RB211 have not only 2 speed zones, but 3. So does that mean that these engines need substantially more engine maintenance ?
The motor is insulation class F, but it is also 40 years old.
The RR three spool engines offer some of the theoretical advantages similar to a gearbox. At lest the core and intermediate can be smaller and turn faster. They are much lighter than two spool engines of similar thrust, but tend to have higher fuel consumption. All the big engines are very expensive once they hit the shop. It is hard to generalise which engines are more reliable, as each manufacturer has a family of models and is constantly trading reliablity earned through experience for incresed performance at each new model.
Cracking! been looking forward to this!
Glad to oblige. I litterally finished this and had the upload finish at the crack of noon.
As much as it sucks to say, I'd change it out now. Bigger motor but 2nd hand will get the job done and will make it so much better
Other than being easier to set up, I dont see a huge advantage in that.
Variable drive looks well over engineered, Certainly very smooth in reducing induced vibration. I think VAG group (Volkswagen Audi), use a Hy-Vo chain, looks weird.
For inverter duty, maybe worth a high voltage insulation test, I think WEG do a calculator based on motor size/class.
I never knew there was a reduction gear between fan and compressor sections.
Thanks for some very interesting engineering facets.
Best regards from the Black Country UK
THanks for the feedback. It is a very well engineered machine.
Thanks for the great explanations...I learn a lot from your videos. (Most I will not use but appreciate learning it anyway)...I got a shiver thinking about the low speed torque....One of the things I like about my little mini lathe is that the breaker kicks with very little load. This turns into a great safety factor for a novice for myself. Crashing the head doesn't break things AND if I were to get a body part in there it probably wouldn't amputate it. (don't want to find out though)....Considering using the motor or not: I would use it for now and if I found a need for that large of motor I would switch it to the need and get the new motor for the lathe.
Yeah, the 7x lathes tend to stall the spindle motor. This machine will make a big mess before it stops.
Also for the mirror it turns out paint stripper will take off the plastic and then you can oxidize the copper to expose the silver. That gets you a delicate but ghost image-free inspection mirror.
This was remarkable clear once I wiped of the big greasy smear on the surface.
That version of the CVT abbreviation is new to me, I’ve heard it called “continuously variable transmission”
In Denmark we also call it a variator.
I probably made that up :/
@@RotarySMP probably, btw great video! As per usual, really like your style of videos.
Yeah, Them geared turbon fan planes are pretty cool. I've gotten to see drawings and how they test their new engine designs for their flight test beds as Pratt and Whitney do air tests with several types of planes. Though it sounds like they are retiring a few of them.
Not sure why they don't break the fan into separate fans with them running at the same tip speed just a bit offset or if they had ring to keep them lined up. Even with a lower speed it should work, but how well is the question
There are a million compromises flying in formation there.
An excellent video because it illustrated the range of things (jet engines) that I know nothing about but find facinating :-) It's always good to learn! In relation to the air pipes if the new tubing fits inside the old can you not use the old tubing as a sleeve over the new where the clamps are?
Good idea. I will cut a piece and try it.
If its about vfd and 3f motor. I've heard the same myth as you said. Few years ago ive done some research, there will not be any problem with bearings due to its limits of rpm.(you can check yours) They are rated to much more than you could run your motor. BUT! theres problem with eddy current. It will heat up rotor and it axis which will damage bearings if you put too many hz through it.
Btw. I run my mill and lathe with vfd, i am not guessing any of this :)
Thanks for the feedback. SInce the Variator is staying, I can be pretty conservative with the VFD speed range.
You have "vinegar and rust mixed with plaster" recycling available?
It will go in the building rubble. Plaster is basic, adding dilute acetic acid , they will neutralise to a few calcium compounds. Rust is not dangerous , except to bridges. This waste is not dangerous or toxic.
@@RotarySMP just busting your chops a little. You said "recycling" in the video, and I would assume the only kind of recycling available for this waste is the kind that involves plate tectonics and a few million years.
I agree with others, keep the motor and most of the mechanics, and figure how to drive it from CNC. Maybe use more modern contactors. It would nice to see this beauty work with all its mechanics.
If that does not work, you can always scrap this idea, and do it other way later.
I will need one modern contactor to isolat the VFD, but otherwise, it will be VFD+CVT+Backgear. Belt and suspenders :)
Your videos are always interesting - particularly with your tangents into aircraft. Now as for your lathe, if you have the potential to coldform wrought iron balustrades then why not keep it that way - jokes aside, cold forming processes may be an interesting adjunct for you - roll hardening, roll threading & roll burnishing on a small machine would be pretty cool & very handy.
Good luck - Stay safe and well :)
I really dont know what usage case could need 600 NM on a 10 inch lathe.
Nice explanation od asynchronous jet motor :-) Very appriciate! I know you worked in aircraft industry, but what position? I really like jet engines and these information are so helpful.
But to your Schaublin - although I love mechanical marvels, personaly i will use vector VFD instead of variator.
#3 fan
I worked in maintenance and in airline engine managment.
I have that Lenze VFD so it will be VFD + CVT + Back gear.
air collet closer is awesome, it would also be cool is someone sent you a (Leader UK/Autogrip Taiwan) 4 inch auto/air chuck....probably the smallest in production
Yeah, that would be cool.
Hello Mark,
I was not aware of the vinegar tip on mill scale removal, thank you. On the motor I would go with what you have and then replace in the future...
Take care.
Paul,,
Thanks Paul.
600Nm is quite similar to my Okuma ACT4, according to charts I have, it has 670Nm in low gear, but with 30hp VFD motor, up to 1200rpm. High gear, 200Nm up to 3200rpm...
Thanks for that info. 200NM at 3200? That sounds terrifying.
You always make me want mooooore! 😄
We all want more Schaublin :)
Would the VFD still give voltage spikes if it's only used to change the direction of the motor, rather than increase or decrease the speed? I suppose it depends on how smart the VFD's algorithm is or if there's a way of intentionally commanding it to do this, but in theory it should be possible to have it just connect the appropriate input and output phases without trying to switch anything.
I am pretty sure the way it chops up AC to DC and then rebuilds AC as a no longer smoothed sine wave is te same regardless of frequency, even if 50Hz in 50 out.
Calculate power and torque for cuts you expect. 600Nm cuts are........ unlikely. Back then, they were probably still considering tool steel cutter surface speeds.
That is pretty much I was thinking.
That motor will be fine with a quality vfd keep it !
I hope so. Thanks for the feedback.
You can run it on any of these:-
Yaskawa
Schnieder
Fuji
@@prashantpanchal9686 The one I bought is a Lenze. Also a quality brand.
You need to upgrade the schaublin drive with a gas turbine engine
I think that huge wide toothed belt might simulate the sound well.
Hey, i really like your Videos.
i worked around 4 years with Schaublin 125 and CCN125 and the one Problem i had, quite a lot was that the variable Beltdrive couldnt transfer all off the Torque form the Motor.
My take on that would be to change the lower beltdrive to a toothed belt and keep the gearbox as is.
Wow, that is an interesting input. What were you turning that needed such high torque? I find it surprising that this little lathe even needs so much torque capablity.
@@RotarySMP well we did quite a lot of stainless on them. That Problem occurred mostly when we did Threads like M12-M16 with a tap.
When the variator is on the lower end of the RPM range the Belt tension is going down a bit and therefore the transferable force decreases.
Maybe it is possible to adjust the mechanic but i didnt had the time to really dig in to that.
And like you mentioned, it would probably be easier to eliminate the variator and just keep a 2-way mechanical gear than to implement the variator on the Software.
Regardless of that, it is a fine piece of Engineering and i liked working with the variator a lot.
@@christianrees9564 Thanks for explaning that. I can M16 tapping in Stainless being a real stress test for any drive system.
I have an avm mas165s cnc lathe that I converterted to pathpilot. It has a 2.2kw (3hp) spindle motor driving a 2 speed gearbox in the head giving rpms of 50 to 1500 and 150 to 4500. In my case 3hp is fine but I could easily go bigger. I'd keep with the 3kw motor if I was you. At least until you have it running then you can up the hp if you find it struggling
Thanks for the feedback. I googled the avm mas165s. Nice looking lathe. Great size.
@@RotarySMP thanks, it's not a bad machine. It was originally fitted with a fanuc 3t control and a 7.5kw (10hp) spindle motor. However I got the machine without any of the electronics. So I decided to go solely single phase. Using a mesa 7i92, custom breakout board with arduino ( to control the turret), Chinese 750w ac servos and a standard 2.2kw 3 phase motor for the spindle driven by a vfd.
Please keep the variator, I am suffering so much without torque I would want as much torque as possible!
Me too. I always hated having insufficient torque on the Mini lathe. Drove me nuts to have to turn to fast, burning up cutting edges, and chattering, because the low down torque was missing.
Fascinating stuff thank you for posting.
But why do you pronounce Linux as "Lyn Ox" when everyone else I've ever heard say it, says "Lyn Ucks", including several Kiwis I know? ;-)
After speaking german for 2 1/2 decades, it starts messing with my english.
I would leave the motor and drive as is. Seems beefy and well designed.
On a side issue, is it true that cable length between a motor and vfd affect the motors life/insulation? From what I remember very short cables really help the motor. Any ideas on that?
I have never heard that before, but am no electrician. I'll ask Stephan, who repaired my Mesa board.
Maybe it is because shorter (or thicker) cables have lower resistance which may keep the voltage spikes on a lower level. In any case, short and thick cables are always the right choice for good performance...
It should also be possible to reduce the voltage spikes with capacitors, but you need to find out which ones are the right ones, otherwise they may get hot or the may damage the VFD.
I know shorter and shielded cables are preferred, but I remember powder coating line with VFDs on one side and conveyor motors on other side, about 50 meters of shielded cable. Worked like a charm for 20+ years.
@@DreitTheDarkDragon SInce the wire is already in there, the right length, with ferrules on the ends, but natural laziness is just going to use it :)
@@RotarySMP Great to hear you are just normal lazy person :) Also I guess most of cable is hidden within Schaublin's metal frame, so it's already shielded good enough!
You can try some citric (lemon) acid for scale/rust removal.
It work same way as vinegar, but it smell much nicer :)
And... you can adjust concentration as you wish.
Not sure for Germany, here you can bye it at any grocery store.
I like the smell of vinegar.
@@RotarySMP recycle it on the fush & chups :) I wonder how many recognized the SHMBO reference? I'm guessing SHMBO would not, which is fortunate for you
@@RobB_VK6ES Selve preservationteaches me to fly under her radar :)
Thanks for the tips about the vinegar & mill scale. I just bought several sheets of steel just like you are using, for a future project after I finish my plasma table. Now I know how to treat the steel for painting. Is there a way to remove dark stains on metal? I got some moisture in my shop while working on the cast iron ways on my mill and ended up with dark patches in various places. Nothing to cause any problems but they look unsightly and it would be nice to make them go away. Looking forward to seeing the wheels go round on the Schaublin. Thanks for all you do.
I dont know how to remove such staining either. I have them on the Schaublin ways.
I‘d replace meanwhile i dunno where you could even get that chunker off a motor. A direct spindle would be even nicer but these are unobtainium + price.
As long as it works, this is the simple solution.
Keep the variable drive but put a hand crank on it. Thank you for the analysis of the geared fan; I'd sure like to see the condition monitoring regime for that gearbox.
With the set up of VFD + CVT + Backgear, I am pretty sure I dont need a hand crank :)
Good point. But other than monitoring vibes, oil temp and Px, soap sampling the oil there wont be much they can do. Another commented that they have some boroscope inspections already but with tiny 2mm light guides, it is a real PITA.
@@RotarySMP I mean use a crank (instead of a motor) to adjust the CVT; all the benefit with reduced complexity.
@@jimsvideos7201 For me that may be increased complexity, as I already have the CVT motor, wiring, and control board. It just takes a couple of output pins from a Mesa card to give LinuxCNC control of it. The hard part will be writting the control heirarchy of when LinuxCNC should change VFD vCVT v Back gear.
@@RotarySMP Fair 'nuff, I look forward to seeing what you end up doing with it.
@@jimsvideos7201 Thanks for your input.
What do you think of the idea of electrical bypass for jet engines? RR are said to be playing with the idea.
I haven't heard of that. You mean burying the gas turbinein and driving a generator, and then having the far driven by an electric motor?
@@RotarySMP yes, it potentially gets around the fan size limits etc. And allow distribution of thrust and possible hybrid aircraft etc. Sounds interesting 8-)
@@wktodd I guess it depends on the losses in the round trip from shaft HP to angry electrons, and back to shaft HP. I cant see it happening for large turbofans, as there is so much beyond efficiency, such as debris trajectories, fire protection etc which would make it very hard to find an airframer willing to do anything radical.
i use a poly v belt instead of the variator. the motor i use is a 2.2kw motor with 1500rpm. i use a 5kw VFD so i'm able to clamp the motor in delta. so i can use the full torque at lower speed and i have 3.3kw at 87Hz. the motor runs at higher speed in field weakening operation to 120Hz with no problems. the use of the 1:6.5 oettinger is a must, but the variator isn't necessary if you use an VFD. if you'd like to give it a try, come over to my 125 ,-)
Good points. Since it is easy enough to pull the motor, I figured I'd leave the variator as is for now, and can still replace it later with a poly-Vee once I get the machine running.
You added an exra fan to cool your motor right?
a geared turbofan is basically a turboprop in a tube ;)
It will be once they put a pitch change mechanism on the blades. :)
@@RotarySMP do the all the turboprops have variable pitch?
@@fuzzy1dk Yes. Fixed pitch props are really only used on ligt aircraft.
GE had a test program called the UDF (Un ducted fan) in the 90's which had variable pitch blades, unshrouded, and driven off the LPT. Kind of a mash up of turbofan and turboprop tech. Great fuel efficiency, but i think noise killed it.
@@RotarySMP …it was also butt ugly.
@@624Dudley Yeah, but if but ugly was a measure of aviation merit, the A380 would be a failure.... Oh... :)
What would I do? Well I know what I wouldn't do - try and grab the chuck with my hand when it's in low speed and back gear! :D Keep the CVT. A quick search - ie based on no personal experience whatsoever - suggests high frequency components from the VFD can lead to large induced currents in motor shaft which if passed through bearings can shortens their life? That said, absolutely nothing on that Schaublin seems marginally engineered. PS. is the name plate clean enough yet?
Thanks. This lathe spindle will not stop for anything. Definitely not a machine to crash.
I was looking for a brush to clean the nameplate, and then forgot.
Can't you test the motor insulation with the same gadget used in aircraft wiring certification? That CVTish drive looks really nice.
I dont have access to a insulation tester. But yeah, it would be a good idea.
Instead of the CVT(continuously variable transmission) you could replace it with some belts and a VFD
I could, but I already have these parts, so it was just easiest to reuse them.
I'm pretty sure original motor will survive. I honestly never heard of output filter for VFDs which people mention in comments, I know only of input filters.
If you plan to run it on lower speed, you might consider replacing motor's fan blades with external fan. You can buy motors like that (I think Lenze actually makes those), practically normal motor with longer body and fan slapped on end, independent of motor shaft. When VFD is driving motor at any speed, it automatically switches contactor and runs this fan on motor at full speed.
Also connection between motor and VFD is usually done by shielded cable. Shorter is better, but I've seen even huge motors 50 meters away from VFD and it worked for 20+ years with no issue.
About transmission, I think you should really keep everything like it is, even if it wasn't used now. For first experiments you can change speed just by VFD and control variator manually, later you can fine tune control of all those transmissions in software. Three "transmissions" in series aren't usual and it might be really interesting to see everything working at once. And you can make TOT jealous of such high numbers :P
Maybe it might be good idea to add some potentiometer on variator (if there isn't one) so you can guess at which gear ratio you are right now?
And one last thing, make sure you understand all parameters in VFD before turning on motor. It usually wants not only nameplate frequency, current and voltage of motor but sometimes other things too. Also there are questions like what will happen when motor is overloaded? Some VFDs can try to keep set speed, some rapidly slow down to last speed which fits set maximum current. And so on, it would be shame to overlook some important settings in manual ;)
Thanks for the suggestions. Really appreciate that.
The power cable is the length of the bed. Wont get it short than that, but it is only about 2m.
I was also thinking about starting with the back gear and VFD under LinuxCNC control, as there are already software components for that. I could just bias the Variator with push buttons. The problem with that is a temporary solution which works is permanent. I need to have a think about the logic to control these three.
Putting some feedback of Variator position is a good idea. I hadn't thought of that.
Luckily I got the Lenze VFD with a programming module and instruction manual,but thanks for the reminder, as I set up my Siemens VFD just as you recommended, first inputting all motor parameters before hook up.
@@RotarySMP You're welcome, I hope my comments won't disappear after sending like on different video some time ago. Actually I tried to post one comment yesterday like three times on different channel and it just wasn't working. Comment is here, refresh, comment is gone :/
Then it should be fine. And in worst case you can wind some aluminium foil around, if there were some problems with interference. But I guess cable will go inside of metal frame, so it's actually shielded good enough :)
Oh come on, it can't be that bad! :D On other side I'm even worse for sure. I'm dreaming for 10 years about building of hobby CNC and all I have are ideas and maybe some really old 3D sketch. I'm changing topology of everything in my head practically every month and it became one of "I'm bored, let's dream about CNC" things. How to make it cheap, simple and robust...and idiotproof, so even I can drill holes (I can't drill three holes in straight line x.x ) and somehow align that whole mess.
That reminds me, how is transmission ratio for that backgear? Originally I wanted to suggest simple deciding function but I got totally lost on how that backgear works. It's just switching in between of two ratios, right?
I thought it might help program to at least know where it is and which way to move, also with some calculations it means one more "speedometer" on your LinuxCNC screen :)
I'm keeping my fingers crossed for you. I was setting up only small Yaskawa V1000 drives and old Omron drive at work and I got really surprised how many things it can do. For example that Yaskawa does have even PID regulator for speed control, crazy! Maybe you'll find something really awesome too. Or at least you will be sure why are some things happening, which can help with troubleshooting later.
@@DreitTheDarkDragon Yep, the back gear uses a pneumatic piston to select between 1:1 and 6.5:1 ratios. Putting feedback on the Variator was already suggested. It is a good idea. Wonder if there is any simple way to get feedback of the back gear position?
@@RotarySMP Hmm, I'll have to check your videos again to see how it is done mechanically. If it was standard pneumatic cylinder, you could use magnetic sensors, since pistons in industrial cylinders are usually (not always) magnetic and there are grooves for sensors prepared.
Other way are induction sensors (M12 or M8 size are common, sensor itself is fine threaded rod with LED and connector), sensing presence of metal. For example you can have two sensors and then metal ring fixed on shaft which slides back and forth in front of sensors. Usual sensing distance is about 4 mm for M12, smaller case (M5, M8) usually means much shorter sensing distance. Induction sensors are also often used to measure speed of shafts (just screw something on shaft to make pulse every revolution).
I was in USA recently and I noticed there are even induction sensors for high pressures, connected directly on hydraulic circuit. I took only photo of sensors itself, but it seemed to be going thru T-piece and sensing piston itself, while pressurized oil flows around sensor ._. Really interesting solution.
And if even that can't be used, I heard of solution which measures air pressure during movement. Not air amount (those must be pretty expensive) but only pressure. Problem is when piston gets stuck, you can't simply detect that. Maybe with good timing you might pressurize cylinder (it should move to end position), then release pressure and measure how long it takes before pressure in cylinder falls - further movement means more air and more time. If time fits expectations, you can pressure it again to hold it in that position.
But I've never seen this in real life, only heard it's used somewhere, I'd take that as last resort. I'm not even quite sure if it works how I think it should.
I'm personally huge fan of induction sensors. It's nice to have magnetic sensors on body of pneumatic cylinder, but it can't tell cylinder separates from object it was moving. PLC is happy to see piston in correct position but part which it was pushing/pulling might be somewhere else.
@@DreitTheDarkDragon This is not a standard air cylinder. The piston assy is integrated into that gearbox.
I seem to remember a car gearbox that worked on the same variable principle. The Variomatic?
I think a bunch of little cars had a CVT, but this a HyVo chain between sheaths, not rubber.
Motorscooters use this type of Variomatic with a rubber belt.
But the gear ratio is changed via flyweights, so it changes automatically with the engine rpm.
That may be a perfect combination with VFD to maximize the torque at low speeds...
@@Henning_S. I hope so.
Don't have it replaced, have it rewound. They do stuff like that every day in India.
I have been watching some of those industry in the indian subcontinent videos. They make my personal safety choices look excessive.
i would definitely keep the original motor. i wouldn't be surprised if it lasts you pretty long even driven with a VFD :)
Thanks for the input. I hope so as well.