Diresta Bandsaw Restoration 32: Installing a Variable Frequency Drive (VFD) for Motor Control
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- Опубліковано 15 жов 2024
- Diresta Bandsaw Restoration 32: Installing a Variable Frequency Drive (VFD) for Motor Control
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I can’t wait to carve on this monster 😁😁😁😁😁💪🏼💪🏼👊🏻👊🏻🙏🏼
Hey Keith, another great video. Remember to finally tune the VFD when you have a blade fitted. Both the blade and the upper wheel will add to the load inertia. If you have a dedicated emergency stop input to the VFD, you might be able to program a separate deceleration rate/time for estop. Please make sure that the VFD can stop the fully fitted load at the fastest rate (minus a bit for margin) reliably without tripping out over voltage. If Jimmy ever needs to use the estop feature, he’ll need it to be fast and reliable. And it’s okay if estop takes the dump resistor close to its max temp, he shouldn’t be using estop frequently. The regular stop can take longer to reduce the energy dissipated in the dump resistor. That should be able to be used repeatedly without overheating the dump resistor.😊
Very good advice and covers the thoughts I had watching this with answers on how to address the issues.
Exactly my thoughts also. You have that monster Bleeder Resistor, time to heat it up with a fast emergency stop sequence!
The estop is most likely to be used while cutting, which will already reduce the momentum. But you need to make sure it will stop quickly when unloaded by a workpiece. This is actually more demanding on the VFD surely.
@@EJP286CRSKW Either way, the estop needs to handle regeneration from the worst case load condition, which I agree is when the saw is unloaded.
I know you often think with respect of the old masters who built these marvelous machines. I imagine they would be just as enamored with what you have done with this restoration!
I picked up the habit from my dad when starting a large saw. He would grab the bottom of the upper wheel give it a yank in the operating direction and then hit the start button. From before the days of soft starts and VFDs.
Like when the start capacitor goes out on a bench grinder lol
What is causing the belt to shift, is that the high spot of the motor pulley crown, is not in the center of the belt. Moving the high spot towards the new bracket (out) will fix the issue. Can be achieved by moving the motor out, or re-doing the pulley to move the high spot of the crown out.
My thought exactly. The motor pulley being crowned like that, and not having the belt centered on it is going to have it track to one side really badly.
Also, if the motor axis is not truly perpendicular to the plane of the belt centre-line, this could be contributing. You could try rotating the motor frame slightly anti-clockwise or clockwise viewed from above and/or tilting the drive-end up or down.
You might try some washers under the motor to tilt a bit because it has a significant effect on how the belt tracks. I just finished my belt sander and had to experimenting with it a lot even when I set everything paralell (best effort)
Yahoo it's been a long time glad it's getting done hope you're feeling well Jimmy is going to love that
As an electrician, all of the points you talk about with the vfd are exactly what I look at when specifying anything really. The main one is the information available.
I know Jimmy will be very happy with ALL the work you have done. It’ll run for another hundred years.
Keith, one setting that may help you belt tracking during acceleration is the type of acceleration you choose. Most VFDs allow for a linear acceleration as default but also have an S-curve option. This requires a little more torque but the acceleration is variable and it eases into the acceleration profile so you have smoother transitions which may (or may not) help the belt tracking.
Congratulations on a beautiful restoration (with the advantage of modern power).
Couldn’t agree more on making sure you have a good manual before you buy!
Are you going to film delivering the saw to Jimmy? It would be awesome to get his reaction
Thank you Keith! I have really enjoyed this project and I learned a lot. Willy from Freeville
Sounds like there isn't enough crown on the motor pulley.
Can't wait to see this saw making dust.
The VFD was a very good choice. I am really enjoying the bandsaw series.
I think the mixture of old and new tech is awesome. You're not taking away a dang thing from the aesthetic, in my opinion. Its sort of like adding EFI or overdrive to an old muscle car or truck.
The original manufacturer and users of that machine approve.
I had to go down the Chinglish rabbit-hole for the VFD I installed on the old Clausing milling machine I rebuilt. I wanted to get one with a better manual, but, as you say, those were of higher price because of better quality all around, and the price was more than I could afford, even for the small(ish) VFD I needed for this mid-sized mill. It works beautifully, and the need to change speeds by moving a belt is mostly gone.
But, boy, when I then went through the same thing when trying to set up a 5HP 14-inch table saw, new VFDs were right out, at least for me! Thousands of dollars. After lots of scrounging and research, I did get the saw to work for me, with a used 15 HP VFD and a dedicated -- and giant! -- transformer, to take my single phase 120v service up to 440v (I think). And then, after hearing it many times from my son, I realized the saw was much too large for my shop. I had scrounged so well, though, that when I sold the saw, I made a decent profit. Not on the time spent by any means, but that's okay. I learned a lot, and I got a lovely old machine working again. It's now down in Central America, installed in a saw mill.
What a beautiful machine and now it's a beautifully functioning machine. Jimmy has to be chomping at the bit to get this beauty in his shop. Thanks for the video.
That's pronunciation of potentiometer gets to me. 😂. Good video regardless. 👍🏻
I agree with you wholeheartedly about getting equipment and other things from Korea & Taiwan and not China. I had something a few years back and the instructions manual had places that made absolutely no sense.
Definitely the way to go. I know you love to keep things authentic, but adding some modern safety and control, is just sensible. Good job.
My thinking exactly!
Yep…. Original … but using technology to make it much safer to use.
Well done mate 👍
Robert
Lovely job there Keith, its always worth taking the time to do the job properly. The fact if it runs so quietly is testament to that.
Very good advice as to reading the manual. Mind, I recall a Toshiba manual that was an inch thick.
A great blend of antique and modern technology.
Hi Keith thank you very much for all the videos you share with us and the knowledge
I noticed on your frequency drive when it runs it whistles and make whistling sound in the background you can adjust that and get rid of it if you want
Under Operational Noise Settings (carrier frequency settings) Page 4-170
You can drop it down or increase it to see if it make a difference normally I drop it down and it works fine without hearing the motor whistling in the background
Re turning the motor round to give some additional travel. If you turned the motor upside down and hung it from the bracketry, which may need to be beefed up, that would give you the extra travel and possibly neaten the cable route?
Good idea!!!
Absolutely awesome job. Thank You for sharing this video with us. I’m very glad you’re doing everything Your way!
Lovely retrofit of a working antique! Here's to the next hundred years!
so much fun watching. thank you
Currently the electrical system is working under a VERY light load. Once the saw blade is fitted, the start up load will increase and the shut off rotational inertia of the upper wheel will be added to the lower one. Under such normal working conditions, I suspect you may have to modify a few of the VFD soft start and braking settings.
I had that thought, possibly subject to some blade slippage.
Looking good Keith!
I was wondering the same thing
I suspect that if you increase the diameter of the motor pulley, the additional belt contact surface area will help limit slippage and the band saw will get moving to follow the acceleration of the motor better. Also, the larger diameter of the motor pulley would give the motor slightly less mechanical advantage on startup, which would make for a more gentle startup anyway. The final speed can be regulated down to compensate for the slightly larger motor pulley. The VFD, if tuned right, should respond to variances in loading and try to keep the motor at a constant speed regardless of pulley diameter. Good luck!
A great job Keith. Just like making sliced bread. Wait a minute, you can slice bread on the band saw!
Congrats on a great restoration! Can't wait to see it in Jimmy's shop.
It's alive !!
What a beautiful saw❤❤
Just lovely.
Nice upgrade and I believe it will make a better safer saw for its user. You may want to add Mexico to your suppler list , I have had good service and quality from components sourced from our neighbors, I am retired now from a multinational corporation we provided high end polymer to some Mexican companies making electrical and electronic products. I
Made suppliers visits to many of these facilities and was impressed with the focus on quality both through ISO standards in place and 6 Sigma programs to eliminate variability in manufacturing. If I have a choice I by Mexican over China every time even if it’s a bit more $.
Can't wait to see it cut some wood, I know it is getting close. Thanks Keith for taking the time to make these video. I am glad you can work it in your professional life.
And is he going to repaint it white?
You know you're in a good place when the comments run this tasty.
First time I've heard of VFD's! I appreciate the intro. Looks like I could use one of these on my bandsaw.
I was pleased that you mentioned purchasing the VFD from Automation Direct. I have been a customer for over 12 years and have been thoroughly pleased with their pricing and delivery. An even bigger plus is the Automation Direct technical service. They have an exceptional staff to assist with any question. You do indeed get what you pay for.
hey thanks for the motor control info.
Keith,
Tou mentioned putting a cover over the belt, as a future project. If I were Mr. Diresta, I would prefer you do the work. As an artisan you can make the cover match your art restoration work. I would also have you make the blade covers for artistic reasons.
If are asked to do the covers, I would start with Jason at Fireball Tools. He restored a similar band saw and he made similar covers.
As an aside, I think it would be nice if you painted all the electrical equipment black to match the restoration. The grey, white and silver become a highlight. You look first to the highlights and not to the band saw. Your restoration is a masterpiece. Don't let a little paint get in the way of your work.
Bob
Jimmy is well accomplished at restorations and fabrication also. He just doesn't have the big iron machine shop that was needed to do many of the steps in this project.
Some VFDs. Have a auto tune feature that makes setup much easier. I like the big heat sink without the need for a fan.Some are more compact,with a smaller heat sink but,those fans can be problematic in dusty environments.
Keith, sometimes, if a belt has a slightly larger side, it would pull to one side. A simple test would be to flip the belt around and see if it pulls to the opposite side when starting. Have fun.
Dont forget you need to tune the whole drive mechanism with the blade installed. The rotating mass will nearly double once the second wheel and the blade spin up.
I came here to point this out, especially with the energy dump resistor. Don't adjust it to the limit without the whole assembly! When you add the rest you may over-volt the system again.
I'm a huge proponent of VFDs, particularly for large equipment. In addition to the soft start they provide a ton of interlock capabilities and also monitor current, voltage, etc. They protect both the motor and anything connected to it. The variable speed opens up a ton of possibilities for getting the best cuts. Great application. Thanks for the great videos, as always.
About the only thing I can think of is it would be nice to see the EStop trigger 'as fast as possible' spindown vs normal stop being a more... leisurely one.
It's nice to see an old machine run and adding a feature or two that it would never have had. :)
WRT the electrical box - it’s already in the right position. You have to access it hopefully once. If it’s on the back, it is in the way when you walk around it, postion it, etc.
great video
That thing is beautiful!
have to cut a hole in the floor for the drive wheel though.
The load to start up and the momentum will increase when you get the blade on the machine and you add the weight and momentum of both wheels.
I also noticed you have the metal conduit and cables to the control panel crossing the slot in the table where you feed the blade on installation which might be inconvenient.
Some belt dressing would be a good thing to employ.
You are AWESOME! very detailed and well defined! the Bandsaw is a Wonder of the Machine World!!
Keith it's a thing of beauty! You probably covered many more variables than expected but are coming through like a champ!🏆
installing the sawblade will add the inertia of the second wheel. then you need to slow it down faster.
Nice work, almost a new machine :)
Hey Keith, a before and after pictures would be great. It has been a lone time on this project.
Good morning Keith. Really great build for Jimmy. Amazing saw. Thanks.
Nice. I did learn a few things today. Good job.
You have done a beautiful job with this saw.
I usually listen and not watch, but today i was actually watching …. I think it’s been a while.. I’m pretty sure you used to be a lot bigger
Nice job! Always satisfying to watch these long projects come together in the end.
Indeed, take into account that the inertia essentially DOUBLES when the blade causes also the upper wheel to be be accelerated (and decelerated). There is some minor increase in losses, but without a work piece in place (and it is normally not, either during start or regular stop), the time constant and thereby the natural start and stop ramps will be about double. That means, the main stop effect is left to the brake resistor. I hope your more powerful resistor can handle it. But you better evaluate it! The resistor heating also has its own time delay. Same power applied longer, or repeatedly may cause surprising heat, which has to be dissipated.
If the resistors are commercial brown enamel coated ones, they are rated for up to 300 degrees Celcius (570 degrees F). If they are custom wound without a core, like certain room heaters have, they may tolerate temperatures up to red glow, but they still need adequate ventilation. And they do form a fire hazard, for example with wood dust falling on them. The best luck comes to people who know what they are doing, and don't forget their knowledge. So, I hope I did contribute a little to the knowledge base in this case...
Thanks again another great video
Thank you Keith 👍🍺
Keith i am sure you made the motor parallel to the shaft, but my guess is the motor is tilting down some. have you tried a couple washers under the front edge of the mount or cock the motor a little backwards from parallel to compensate?
Looks great Keith.
Most excellent.
Nice job Keith! Quality work
You certainly give consideration to multiple facets of your projects. As such, I'm surprised at how you routed the electrical wires and conduits. Possibly you were concerned with other than aesthetics?
Nice job to both soft-start and rapid shutdown.
I see the VFD is producing 49Hz at top speed. I assume it is adjusted to allow saw wheels to turn at the correct speed. I think it needs a shroud over the belt pulley area.
A whole lot of work. Close to done. Great video.
Noce job. Looks great. I was worried you were gonna deliver it at jimmy's retirement party with all the delays and health issues.
Why do you care?
@paulcopeland9035 just saying life and unexpected delays have a way of slowing down progects
I have had issues with using a vfd off a rotary phase converter. The generated leg is not a true current capacity of the line 1&2. Basically the 1&2 legs go right through the phase converter to the vfd and the generated leg is less current or amperage. You have to think of it as net input (you get nothing more from the phase converter in power total). Put a amp meter on it and see.
Thoughts: Could you get a spacer plate cut to allow for the motor to be reversed?
Next, is the motor shaft deflecting at startup to cause the belt to walk, but then return to the run position? If it is, the bearings will need more maintenance.
Finally, a ten second eStop is probably 9.5 seconds too long in an emergency situation, so how about a wagon wheel brake on the drive pully slow things down fast enough without throwing the blade off the drive wheel ... dunno ... $0.10 ... 🙂
Keep up the good work ... 👍
looking good. both of ya
Hi it would be wise to put a DV/DT output filter between the motor and VFD or the bearings will be compromised as well as the insulation in the motor, the alternative you can install brushes on the motor shaft to short the "eddy currents" to ground to protect the bearings. you can wire the "E-Stop" into the drive directly for a fast stop and with a remote key pad you can read the speed out.
Rich
The E-stop MUST be a fast stop. Keith did that wrong.
Remember that there is the upper wheel to accelerate/decelerate too. Also, will the belt drift off under load?
Thanks for showing how the VFD can be used for speed control. It may be a good option for my belt drive Gorton Milling Machine. I could set up the belt for max speed and use the VFD to control speed of the spindle motor.
Definitely yes for your mill I have one on mine, and can run @120 hz or more for double the normal speed for small diameter end mills, or slow to 30 rpm for tapping with no belt swap... Would not be without it!
Rather than set up for max speed, choose more of the middle speed for better torque at low rpm for big drill and tapping...will still h as have good upper ranges by double or more hz
Great tip. I just noticed that the frequency output of the Iron Horse went up to 400hz. What concerns are there when increasing the hz and speed (other than mechanical RPM limit) and what model of VFD do you use? @@jimliechty2983
Could you have made and install a flange on the end of the motor pulley? Most of the conveyor belts we had at the gravel plant had guide rollers that would keep the belts centered. Mounted on the slack or non pulling side. Nice job with the VFD.
Thank you for sharing.👍
Thanks Keith!
Just a question, what about painting the wiring connectors black to blend in to the saw frame? That will sort of hide them. It would only be for appearance, not operation.
And paint the top, sides, and back of the VFD black also.
How much more momentum will the blade and upper wheel add? Looks like double to me.
Definitely a better choice in this application. I wonder if it would be better to have the e-stop brake the motor as fast as possible.
Another thing to worry about is the nut on the wheel is you stop it too quickly. We had a big radial arm saw (7 1/2 HP) that had a blade brake added. If you set it too fast, the sudden stop would loosen the arbor nut of the blade. And you don't want a 22 inch blade getting loose. And a 48 inch drive wheel could be nasty if it spun off.
Happened to me on my old radial arm saw in my basement one day. Boy was that scary. I dropped to the floor and crawled out of there in under two seconds.
If I ran into that problem, I'd loctite the nut &/or if there was enough shaft sticking out, you could drill a whole through it
& insert a cotter pin. You could even make a castle nut w/cotter pin if room allowed.
This is comming from motorcycle engineering. You got me thinking on an interesting problem.
@toddk.5873 We did add a jam nut and it stopped the problem. But I'd rather they were aware of a possible problem before it bites them.
Another thing that seldom gets mentioned concerning VFDs and motor speed control is that there is a minimum speed the motor must run at to cool properly. If the motor is operated below that speed the fan doesn't move enough air through the motor to keep it cool. In most VFDs this can be programmed in so that the motor won't run below it's minimum.
This is likely not an issue in this application where the cutting load is going to be of short duration and light on the torque. It's a different matter your application is trying to get the full 7.5HP at 20 Hz . Same thing as paying attention to the duty cycle on a welder.
Love this!
I'm surprised you didn't get the VFD from American Rotary.
He mentioned in a previous video AR doesn't make their own VFDs - they just source another manufacturer's products. It looks like they resell ABB brand VFDs - a Finish company. Not sure where the product is actually made, but they are very expensive, industrial grade products, probably overkill (and overpriced) for what is needed here.
Looks like your controls would be hard to reach if you had something that over-hung the table. Working around the open wheels and exposed blade is a challenge for placement though.
What a nice machine, Keith. It's definitely at the top of its class. I wonder where Jimmy is going to put the DiResta brand, and what it will look like?
Glad to see a VFD being used. Maybe some purists will object as this is a vintage machine. Then again the VFD will extend the life of the machine meaning future generations will be able to see it working. As for the EStop, maybe a mechanical brake held off by an electromagnet. Modern commercial bandsaws stop when flesh gets too close to the blade but then parts need to be replaced.
Keith - can the EStop button activate the fastest braking ? If you hit emergency stop, you kinda want it to stop quickly as possible.
Not sure if will help to keep the flat belts running true on the pulley but a 'UA-cam' channel called "steam-powered machine shop" has his pulleys beveled with a ridge in the middle to keep the alignment of the belt on the pulley. (He also runs various widths of leather belts).
Just a curious question - have you considered a soft starter? Not as flexible as a VFD, but much cheaper. You'll always end up at base motor speed, so you can't modify the target RPM, but you can vary the ramp rate. I guess it depends on the application, just wondering if you have used one before...
Looking at how much effort you have put in this project 700 would seem to be about right.
Thinking add more crown to drive pulley
At 20:18, there is a short discussion of a belt guard. Will there be no BLADE guard on this bandsaw?
You probably can program the E-Stop for a harder deceleration; If you are using that function it usually means that "something has gone bad" and you want the machine to shut down pretty rapidly. You just need to know the limits of how hard you can brake (like for an entanglement hazard, you do not want to be slowing down for five seconds). Maybe normal stop is 5 sec but E-Stop is 1 or 2 seconds (also determined by the wattage rating of the resistor and the error code tolerance of the drive).
Will having the blade on, with two wheels and friction from two wheels make any difference to the spin down time?