MACHINE SHOP TIPS
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- Опубліковано 11 вер 2024
- Tubalcain installs a digital tachometer on his drill press.
This is a big improvement on the method I used in video TIPS #141
My website www.mrpete222.com
For tachometer, do an ebay search for this, it is $16.
Hall Proximity Switch Sensor NPN+ 4 Digital Red LED Tachometer RPM Speed Meter
Mr. Pete, I enjoyed viewing your travails with the VFD. About 10 years ago I got an old 13" South Bend lathe with a static phase converter. Of course after a couple of years the old converter failed and I searched and eventually found a controller similar to yours. My installation solves your battery problem and (I think) your speed display problem.
The controller has a 10VDC terminal and a 0-10 V remote control terminal. I purchased a volt meter on e-Bay for under $10. It has a back-lighted digital display. I put it in an electrical box 1/2 the size of yours. Tap onto the 10VDC and run it to a potentiometer. Then run to the meter and back to the 0-10V remote terminal. The result is that the meter lights up to tell me the power to the lathe is on. When I hit forward or reverse the lathe starts at the speed set by the pot. Turning the pot gives me a reading from 0.0 - 10.0. I mentally convert that to 0%- 100%. This tells me the percentage of maximum speed obtained at that belt setting. You can make a chart for each of the for belt settings if you want to.
The best thing is no batteries. Simple control setting by turning the knob like on yours. The meter provides a visual reference to show the controller is pulling power. It would be simple to do the same thing and use your hall sensor and direct readout on the 10V + 0-10V control terminals.
Something I love on my lathe is that, since it came out of a high school, it is fitted with a brake band on the spindle. There is a lever with a big knob sticking out of the head stock. If you tap the lever it fires a micro-switch which kills power to the lathe (I suppose it is for the teacher to be able to stop everything). If you push hard on the lever it kills power and stops the spindle! I use that almost all the time as it saves me from having to reach across the work to hit the South Bend control switches over the back of the lathe. I mounted my meter and control knob to the South bend control button box where it is visible, easily accessible and out of the way. It's been working fine for about 8 years now.
The controller itself mounts on the back of the lathe near the floor where the converter used to be. The only problem is if something goes wrong the converter goes to error mode and requires that the reset button be pushed. I have to climb behind the lathe to do that. The other thing I don't like is the chips fall on the ventilation slots of the controller... Your great idea of a chip guard is now on my project list!!!
Thanks for a great on-line shop class. My wife is getting tired of me watching a Tubalcain a video or two every morning on my phone before getting up out of bed! (Maybe more information than necessary here!)
Hi Mr. Pete,
I went back to your video #138 and noticed that your VFD had what looked like a DC output that was flagged with red tape by the manufacturer. If the output is non-variable, 8-12vdc and useable, you could just power your LED display from the VFD itself and not have to worry about separate power supplies/batteries. I'm sure the user's manual would let you know if that portion of the terminal block is useable or not. Just a thought.
Keep up the good work. Am enjoying all your videos.
Best regards,
RS
Since reveiwing your vfd install videos, I have a couple of suggestions that may suit suit your needs better. The first, is that if you are worried a dust, debris or damage, the vfd may be better suited to be mounted away from the drill press, the program it to use the remote controls, instead of the buttons on the vfd itself. You could use your existing on/off switch the power the drill and you already have it set to use the off vfd pot switch. My response below about power to the tachometer was answered by the orange sticker on the vfd that said "DC". I'm sure that power could supply the tach, if not, there should be some sort of 9v dc power from a 110v charger setup. As far as your disappointment in the low range torque, go back to the slow speed idler setup on the drill press, so it is setup in the absolute slowest range you can get. You should be able to get good torque at low speed. For faster speeds....the vfd will work fine even if you operate it a 120 or more hz.....hope this helps! JIm
This is a great and informational video! Put a VFD on my 15" Sheldon Lathe and put a tach exactly like yours with the same problem. Cure was to buy a small trickle charger from FREIGHT company for about the price of a 9 volt battery.The on/off switch for the lathe is wired to the VFD and to the charger and powers them both up at the same time, problem gone! No more batteries for me!
Good idea. I put a walwart on mine & let it run continually--but also has a toggle switch on it.
Tubalcain,
I love your machine shop tip videos. Some of your viewers have already mentioned using a DC power supply so you don't need the battery.
You mentioned in your video that you would like to to have the tachometer automatically turn on.
This is one way you can do that -
You could you a 110vac coil relay that could be wired in parallel to the motor of your drill press. The relay contacts would then take the place of your switch to turn your tachometer on and off that you showed in the video.
So when you turn the drill spindle motor on the re relay would energize, and that would close the contacts an turn on your tachometer.
You can probably find suitable parts at radio shack.
I hope this helps,
Mike
Mr. Pete, To save battery and to make it so you don't forget to turn if off you could run a jumper from 10V input on the back of your remote speed control knob to the tachometer, eliminating the need for a battery at all.
many many thanks mrpete, i always look at your videos on youtube and almost every time i find an answer in your chanel for my problems, i'm very new with machines but i'm getting better and better, in fact i did not really study for this but i love the way the metal chips fly away when making a parts on the mill and my little lathe. thanks once again...
I like the idea of using the DC motors. Depending on their voltage, a full wave rectifier and a variac would work just fine. Both are very cheap. You could add some smoothing caps if desired. I think I would have done sort of the opposite of what you did as far as speed control. I would have left the jack shaft in, set belts for the absolute lowest speed and used the vfd to INCREASE the motor speed when needed. As you have found, you will never get usable torque from a motor at 20% rpm. The motor heats up because the reactance of the windings is lower as frequency decreases, the slow fan speed doesn't help either. The "torque boost" makes the heating worse. Great job an the Hall effect sensor! Can you say where you got your vfd? Great videos, thank you for taking the time to make them!
The torque of an induction is largely a function of the current running in the rotor (which is obviousy limited due to thermal issues). Running an induction motor with the variable frequency drive allows you to achieve its rated torque at any speed. You can't however get any more torque then rated because then you'd burn up the rotor. So you basically have constant torque over the entire speed range (thus lower power at lower speeds).
With mechanical reduction you directly exchange lower speed for more torque and the same amount of total power (minus losses from friction in gears/belts/etc...).
Hi Pete!
If you change the parameter for control mode from "Volt per hertz" to "Sensorless Vector Control" you will have a huge difference inn torque output at low speeds. Usually 100% torque at 5hz (depends on manufacturer).
I've just read the spec sheet and the Teco supports this control mode.
Thanks!
Regarding slow speeds/low RPM. It is actually not a problem of the VFD to drive the motor at slow speeds. The key issue is that the inductance in the motors turnings work as resistors when the frequency gets low. So in principle you are driving the motor with a slowly switched DC ...
That is a bit oversimplified but remains the same issue e.g. in driving motors in electric cars/trains.
There is also an issue with too high frequencies. That can also have a negative impact e.g. fast turning stepper motors where the inductance is to persistent for the frequency - thus keeping the winding 'magnetic' to long. Nice video - as always ...!
I've had a VFD on my Bridgeport since I first got it a few years back. I keep it running between 25-75 hz. I'm able to do 95% of machining in the second speed [J-head like yours] by using back gears for slow stuff when the motor would get bogged down in lower speeds.
I think you're going to be much more impressed with the VFDs capabilities on your mill or lathe.
Mr. Pete. Another wonderful video. This video is 2014. I'm sure you have the answer now. An auto transformer or variac can be used for your dc motor controller. You simply use a bridge rectifier and a electrolytic cap across the dc output of the bridge rectifier to filter the dc pulses a little. Make sure the voltage of the electrolytic cap is above about 200. The capacitance is not critical. 20 mfd would work. More is better. That is how I am running my logan 820 and my 12" craftsman band saw. It works great and has plenty of torque at low rpm. I am using a 3 hp treadmill dc motor on my Logan. The dc motor is super smooth and has eliminated all the vibration in the Logan as compared to how it was with its original ac motor. I bought the dc motor on Ebay for about $100. I'm sure you could get a used variac on Ebay but also Grainger has them. As for your tach yes I agree with a gentleman who posted below. You can easily find a 9v dc "wall wart" transformer and wire it in place of your 9v battery but you could also do the bridge rectifier trick with a electrolytic cap with any small 6v ac transformer. The cap and the rectifier steps the voltage up slightly. 1.414 X 6v = a little less than 9v which would most likely run the tach OK but the wall wart is the easiest choice.
One of the early video's, someone mentioned that you could put the pulley ratio in a couple parameters, and then change the readout to show actual rpm with the teco drive display instead of hertz. That would save you a lot of batteries.
Hi MrPete, thanks for all your videos.
I'm licensed elctrichian as well as a Machine Mechanic, with considerable experience in electronics.
Here is a tip: You have 10VDC across the potentiometer (0V at one end, the 10V Ref. voltaga at the other end. As the Tachometer is only bound to use 10-30mA, you should be able to use that voltage instead of the battery.
At least it is worth a try...
Mr, if you van help me , I want to know the connection circuit of a tachometer in a plastic injection machine, to make the automatic cutting
I use rechargeable batteries for everything these days..
thanks as always for sharing your experience and knowledge Mr Pete, love the videos
Mr. Pete,
There is a ton of 12 volt DC power supplies on E-Bay. But you could use one of those appendages that powers some other old device you have at home as long as the current it produces is sufficient. Good luck. I enjoy your videos very much.
Tom
I just finished powering it with an old phone power source 9v. Works well.
As I'm about to do this setup on my Holbrook lathe, this series of videos has really helped me a lot. Thank you very much and merry Christmas
I'm glad I helped
Just grab a DC wall wart power supply. They have a bridge rectifier and even sometimes a voltage regulator in them. Radio shack should have lots of options. You can even get adapters for the barrel plug that connects directly to the 9v battery clip.
I just finished powering it with an old phone power source 9v. Works well.
Lyle,
You have inspired me to add a VFD to my DP, which I use for lite milling. You did not mention the motor on your DP, I ordered a 1.5HP 3ph motor for mine. The 3ph preforms better at low RPM's. Also as others have suggested to add the "Wall Wart" to power the RPM readout, I would not recommend taking the power from the readout 10V source, as it is likely to be a low power source and could damage the readout. If you can take it directly from the wall wart, there will be no danger in damaging the readout circuit. I should also mention that I drilled my Quill shaft to accept a drawbar. I am aware of the dangers of milling with a DP
Hey that is great, I love your video's and agree with your thoughts on live in america.
Keep up the great work.
I was worried that running the motor at lower frequency, you might lose some power. Edison would be proud of you for touting DC Motors. lol I like it when youtubers show videos with warts and all. Not everything goes perfect. Keep Machining.
It was a wise decision to use an external power source for Tachometer. I checked the TECO user manual. The VFD's potentiometer 10V line may not have enough amps to power LED Tachometer.
Regarding the lack of torque at low speeds, there are some VFDs + Motors that can increase the frequency on heavy loads at low speeds. They increase torque automatically to keep RPM constant. These VFDs have an encoder feedback line from the motor. I believe they are hell expensive.
hi I have had a lot of dealings with vfd's and have found the best way to get the max out of the motor is to set the gearbox to the slowest speed setting and then set the max frequency to around 100 Hz and the min to around 15 hz as for the power supply you can get several cheep dc power supplies that with give you 9 vdc
Thanks
Concerning the handheld laser tachometer in the blue case; I have had one of those for several years and it has always worked well, but I would advise taking out the 9V battery when not in use for a while. The TEST button is very sensitive and the slightest weight on it, even the case, can hold it ON. It draws 57mA in this case and you will find the battery drained the next time you try to use it.
The whole purpose of a VFD on a drill press is to vary the speed, not to provide ultra slow speed operation. The reason factories use VFDs is not to do away with DC motors which are rare is a factory, but to eliminate the huge start up current demands of 3 phase induction motors.
Left side of your vfd is a sticker that says dc, that is where you can tap in for your tachometer. Also change your belt to accommodate the slowest speed that is usable to you, and then you have some higher rpms if you so desires. Just my thoughts
I put a 3 phase motor on my milling machine with a VDF, and had same as issue as you. -NO Tachometer on drive freq. I bought the same type of RPM meter you did, but my VFD has a 12 VDC power supply built in for access. . So I wired the tach to it and it works well! No batteries! I still use the belts and pulleys system but use the VFD to tweek the RPM to calculate feeds and speeds.
Hi, I have the same portable digital tach and at low speed you have to point to the reflector not directly but with an angle and that will fix the speed reading. Just use one relection tape.
For auto-off on the cheap RPM display you can use as a reference the 10V from the VFD (assuming you will turn the VFD fully off) -- Then a darlington transistor or a mosfet can be used with the 10v and a resistor on the base / gate, to turn the display on and off, based on that 10v signal. It won't draw much current at all, it's going to work as a switch mainly. Of course you'll have to share grounds. Your best bet is to find out if there's an auxiliary power supply you can tap on the vfd, or use one of your own 12v power supply.
LED displays use a lot of current, so I expect that a little 9v battery isn't going to last very long anyway. What you could do, is wire a small AC-DC power supply IN PARALLEL with the drill press motor, and use the DC output to power the RPM accessory. This way- when you turn the drill press motor on and off, you simultaneously turn the power to the RPM accessory on and off. For this to work, you have to connect directly across the motor leads on the drill press- because you want the the drill press on/off switch to operate the RPM accessory along with the drill press motor. Simple(?)
Thanks
Lyle, I didn't read through all the comments, but maybe install a power supply from a hobby shop. Something to plug in.
I also noticed your frustration regarding the lack of torque at low RPM.
I imagine re-installing the intermediate step belt wheel will solve that problem nicely.
I doubt that the power lost to this extra belt step is significant, and after installing the tachometer you always know the actual RPM anyway.
Also at least worth a try as well...
I'm sure if you look around the house you could fined a wall transformer from some old gadget you don't use that is between 8-12 volts and just wire it in to where the battery goes. Just use a multi meter to fine out what side it positive on the leads.
A 9-12 volt wall wart like for old electronics that have passed on is what I would use. Just double check plusitive and minusitive before you hook things up. DC motors are great for having full starting torque. DC motor drives are available from places like AndyMark robotics and can be controlled by servo testers.
For a drive for your DC motors search for Dart Controls.
Have had real good luck with them. Have about 6 of them on different machines
around the shop. They even seem to work better and have more torque than an Allen-Bradley drive I tried. I'm not affiliated with Dart, just a happy customer.
Ok, because of one of you videos I bought a VFD to control a one horse 3 phase motor on an old Walker Turner drill press. From the instant I turned it on I was totally impressed with the performance. From 120 volt single phase to 220 3 phase, what a huge difference this has made for me. Thank You for enlightenment but I'd like to say that in no way can I stop the spindle at low RPM. This thing will twist the work out of the vice or break a bit before giving up. What's is the problem with yours? As motors burn out they will all be replaced with a 3 phase motor and VFD. Keep up the good work....born in Aurora
+Uts9000 Thanks
Man after my own heart - metal circuit box is great protection and super cheap. Function first then form.
_Dan_
👌
Another great video, thanks. I guess you need to build a gearbox for the drill press so you can just select a speed with a gear instead of moving pulleys.
You already have 10volys in that box from the VFD to the potentiometer , just run a lead form that to the lcd display
:)
Now that is a good idea!
I just finished powering it with an old phone power source 9v. Works well.
know this a but late but I was going to also indicate the existing power source from the VFD unit...... can connect directly from the potentiometer on the plus and minus sources in the box
Hi mrpete the company that made your VFD also sells a tachometer for $70.00 that is powered by 110 volts.
I think the idea you had of using a 9 volt phone charger for the tacho was for the best. All you'd need then is a 9v battery lead off eBay and you forget batteries from then. The phone charger wouldn't need to be too hefty as long as the output was regulated. $10 max for everything
the "old" style of "cruise control" on an automobile worked using the hall effect
Thanks
You can buy a switching AC/DC power converter from most electronics shops. They run about 20 dollars. Select your 9V input and you're off to the races.
I should have read all the previous comments, I see now that it had already been suggested :-) Thanks for the vids.
Hey.
You use an external speed potentiometer regulation for VFD. His has such connection 0: Control: +10 V, you can use 0 and +10 V to "Feed" tachometers.
Yes this is the torque decreasing reducing Hz After my own experience I used extra reduction gears 2:1 and VFD frequency limit is 25Hz-100Hz. Just watch out for that the motor bearings can be baked.
Increase frequency better than decrease, increasing the frequency torque increases.
An DC motor also have some problem with torque at low speed. Torque are determined by the current the motor pulls, as are the heat given off. But the voltage over the motor will be low, cause the speed makes the "reverse voltage" that resists the current flow. Thus the available power from the motor will be low. An geared motor on the other hand gives full power because it runs at nominal rpm.
pete you can get rid of the battery very easerly,
you already have 10 v in the tacho box already, just piggy back on the 10v on the speed controller pot the one that goes to the vfd, easy
VFD pinouts (have a look at the wiring diagram)
9 is +10v dc
11 is 0v.(com)
just connect to this in the tacho box for the suppluy of the tacho !!
Yes, that's smart solution!
Just not to overload it compare the dispay power consumption to your VFD 10V referrence output maximal allowed current .
jon white
So, use 9 as pos & 11 as neg--I will do that.
mrpete222
yes that will work, there may be a way to increase low torque at low speeds as well,
there may be a setting in the setup of your vfd that may increase the torque at low
to increase the torque you have to increase the current at low speed, i will have a look in your manual to see if it can be done keep an eye out if i answer this message
***** Even if the VFD isn't able to source enough current to run the RPM display, mrpete222 could still use that to drive a relay. Given that he mentioned he has a ham radio in the basement, I'm sure he'd know just how to hook up a relay. And if not, his subscribers (myself included) could provide help.
Pete, there's 120 va convert to 9v dc power converter that you can use for your Techometer. Geton ebay and type "9v dc power supply" and hit search. You'll see lots of them out there.
Hope this will help.
yep...deff go with the wall wart idea. there's tons of em on eBay, or partsexpress.com. the most common ones will be 5v 9v or 12volts dc.and they're life savers when it comes to powering battery eaters...or small elec projects.
personally..I agree...nothin beats a good dc motor.
Hi Mr Pete, just a thought. You removed the intermediate pulley which if I'm correct allowed you to select the lowest possible speed. You may get better torque if you first replace that pulley and set the drill speed to its lowest, and then use the VFD's higher frequency to drive the motor faster than normal to achieve the upper speeds that you require, hope that helps.
I have already done that & it made a big dif.
Get a 9 or 12VDC "wall wart" power pack and connect it to the battery connections. You can still have the switch in the circuit if you wish. Since the power pack is plugged into a 115-volt outlet, it won't draw much current if the unit is left on.
Dave
I just finished powering it with an old phone power source 9v. Works well.
You could use a momentary push button. Just press it when you want to read the rpms.
+John Sinkiewicz Thanks for watching
I purchased a Hitachi VFD from Dallas Drives -- it is a 220 volt model- for 3 HP motors
purchased the High Torque model -cost a extra $100 but it has Lots of low speed torque and have never stalled it at low speed -- use it on both my Clausing lathe and Bridgeport mill -- if I use low speed for extended amounts of time I put the machines in neutral and increase speed for a while for fan to cool motor - seems like it cost about $300 - 5 years ago -
Great!.....so much for me sandbagging on building my remote switching station for the vfd controls, on my Rockwell mill. The rpm readout was all that I was missing, and was looking for my vfd to supply the info......you just gave me the solution!.....you might look at supplying power to your tachometer from your vfd. They have a built in power supply for 7 to 10 volt....not sure if it is dc or not, but think it should work. I need the info to obtain the tachometer device, Jim
Try using a momentary switch for the power to the tach. You can then press and hold the button to see the speed while adjusting and it'll minimize your battery use.
You could put one of those timers like they use in storage areas that you turn the knob used them they work fine think they start at about 1/2 hour to 1 1/2 there made for 110 v but I've used them on 12 volt you can get them at places like Home Depot or your local hardware store
Hi Master,
I suggest (sorry for my English, I am a German) the easiest way is not to use a switch, but a hold down key. As long you hold it, you will see the RPM, if you release the button, the system will directly shut off.
Regards Michael from Bonn, Germany
YES--a momentary switch. This is the best idea yet.
mrpete222 Thanks, In Old germany there are momentary swichtes with same dimensioins as your switch, so you do not need to change the mounting.
Hi mrpete222....why not use a tachometer to get the speed say 100,150,200 etc...then mark the position on the box?...and then you could switch the box off forever (or at least until you want to check things have not changed)...you could have marked this on the VDF control, but it may been a bit small..I have watched 100's of your videos...thanks very much for all your hard work.
Great video! I've learned so much about VFD from your series with the drill press. Couldn't you use the 10VDC from the VFD potentiometer to power the Tachometer since it can handle 8-12VDC?
Thanks for the video very helpful and motivated me to give this a go, but with some changes to get proper torque. The thing to remember with these setups is that below 60HZ the available motor torque is constant and the speed is variable meaning the available hp decreases as you slow down which as you demonstrated is undesirable. Above 60hz you are in the constant hp zone and as you speed up you trade speed for torque to remain at the same hp which is the same as with changing pulleys. They sell special vector duty motors for these drives which you can pick on on eBay for a reasonable price (they are more expensive than regular motors by default). One of the most important differences for your application is that they are designed to run above 60hz without vibrating. The one i got, runs at 1800rpm at 60hz but is designed to run vibration free up to 5400 RPM. I keep my drill press in the 45-120hz range on the drive range which gives plenty of torque and a reasonable speed variation on all the pulleys.
Thank you--those are good solutions
In Shop Tips 141, you mentioned using a laser printer to save money. I did the same thing and found a place on line that sells the toner powder and a soldering iron with a cookie cutter deal that melts a hole in your used cartridge so as to avoid any chips messing it up. Now I just pop the plastic plug they send out, pour the powder in, replug it and get to printing again. It is REAL cheap this way. The place I found is called 123refills.net but there are others as well. I don't work for them or anything, just wanted to share my small respite from Onomics. Thanks for sharing your knowledge in the videos!
YES--I will start refilling. Thanks.
You could have and still use a bicycle speedometer. They run for more than a year on a button (watch) battery. They cost as little as $6 dollars and display RPM as well as running time.
If you don't plan on changing pullys. Check the speed one time at various potentiometer settings, write each speed in a arch above the pot knob Then turn the tach off all the time, return it for your money back.
Hi Lyle-
Just a thought, maybe asking for
for your tach that is eating batterys use a 12v door bell power pack and keep it pluged in. love your video's
Unfortunately you do need to use the pulleys to allow motor to run faster. Have one on my 17 inch delta and works pretty nice.
Hi
I know you like your new found electronics and all that but may I suggest away of saving your battery from draining, you could use a simple push switch spring loaded to the off position as you only need to display the output when setting the speed.
Try a small wall charger. A lot of the phone wall charger/transformers have a 9 volt dc output capable of 300 + Ma. I have used these for many projects that require batteries.
I just finished powering it with an old phone power source 9v. Works well.
Lyle
Change the belting will help with torque to a point
To turn on the VFD when the motor is on, buy 1 small 120 vac relay 2 pole, run wire from power switch of drill press to a small 120Vac relay in your 4X4 meter, tie that to the coil wires. of relay. Then run one leg of the battery wires ti the contact points of the relay. .....done.
You've got some DC outputs from the VFD- there is, for example, that 10V ref. I have no idea if there's a spec in the manual for how much current it can source, but it might just be enough to run the tach.
Hi. The simplest solution to me would be remove your on/off switch and replace it with A momentary on switch so your circuit would only be active as you held the button.
Hope this helps.
Alex.
That's a good idea
You usually can't get more torque out of a motor with a VFD, however you should be able to get double or four times the speed (with half or 1/4 torque). So, if you can get more speed reduction by putting the 3rd pulley back into the machine, or replacing the pulleys, it should work much better for low-speed drilling, but still go up to a reasonable rpm if needed. The reduced torque at frequencies above 60Hz should be offset by the reduction, and you rarely need full torque at high speeds anyway. And there is less risk of overheating the motor.
The secret is more gearing with faster motor speeds and possibly a larger motor.
If your motor bearings are good I would not be afraid to take that 1725 Rpm motor up
to 4200. I have a 20" Walker-Turner drill press with a 1-1/2 hp 8 pole motor that normally runs at 855 rpm and have the VFD run it up to 2500 Rpm with a 2:1 ratio
on the pulleys. Can drill with a 1" twist drill through thick plate with no problems and
still go up to 1250 rpm for smaller drills. An 8 pole 1-1/2 hp motor puts out the same
torque as a 3 hp 1725 motor, in fact its in the same frame size as the 3 hp.
You should have thought of this one to use as a reminder.....a rubber band or a piece of "Red" not pink or blue "Red" (lol) on your index finger of coarse you have remember to put it on (Ooops) another thing (lol) preferably on the hand less used. And then again you may already use this method to be sure and pick up some bread and milk.! I know you can do it Mr.Pete I just know it ! O_o
find a cell phone charger that is in 8-12v and hard wire it. Ebay even sells a 12v motion sensor that you can use to turn it on and off when you are in front of the drill.
Use the same source of power stepped down to the required voltage for your tacho. Then when you turn off the drill at the wall off it goes.
you can get a 120v ac to 9v dc transformer
Concerning your torque issue- didn't you eliminate the intermediate shaft? Why not add that back in to allow for faster motor speed, and thus higher torque? You can always use the VFD to bring the spindle speed back down.
I will do that
If you are still eating batteries go buy a wall wart style AC-DC plug in the desired voltage output, cut the end off and wire the leads to their respective spots on the tachometer.
You could use the output relay on the VFD to switch on and off the display. Set parameter F21 to 000 and the relay contact will close when the VFD is running. thus turning on the display.
I just finished powering it with an old phone power source 9v. Works well.
connect a 9v. pos / neg lead connector (radio shack/eBay) via black & red wires from box to 9v. DC. power pack, plug that into timer and set time for shutoff.
Ever thought about a variable weighted pulley for torque using a spring setup on the top? Changes sizes with rotational speed to achieve good torque at low RPM
Using an inverter duty motor and controlling it with vector control instead of volts/Hz would result it full torque at low RPM. The problem is that the voltage lowers as frequency lowers.
One of your previous VFD videos show a 10 volt power supply on the internal VFD header. You could use that for the external tac. You'll want to check what the maximum amperage the vfd will supply on that header to what the tac consumes.
I'm assuming the external pot is uses the 10v header, the ground header, and I assume a sense header for the middle contact of the pot. You may just need to connect the tac to the 10v + and ground. I don't think that will effect the pot operation.
I was thinking the same thing, plus I think that there's two 10V outputs and two grounds on that model, so you wouldn't need to tap in the pot's source
As always, thanks’ for taking the time to make this video! And I support this site. ~M~
You could also ditch the walwart and just it power it directly from the VFD 10v output and common terminals. Just be sure the 10v terminal can handle the load, I imagine it should all day long. Should switch on/off with the VFD to boot.
+Duane Bishop thats 10v reference not power source! the inverter could behave strangely with this!!!
This might be dumb, but wouldn't a cheap 12 volt DC charger for car batteries work? I see them at auctions and yard sales all the time. I'm not sure what amperage the tach draws but I would think for a easy fix it would work. Love your videos by the way.
YOU CAN GET AN AC RELAY AND WIRE IT TO ONE LEG OF THE MOTOR POWER THEN WIRE THE NORMALLY OPEN CONTACI TO THE SWITCH OF THE READ OUT. IT WILL TURN ON WHEN YOU START THE DRILL.
Usually there is a 10V out on a VFD that supply a potentiometer or other AUX, so you can use to supply your TACHO.
I just finished powering it with an old phone power source 9v. Works well.
I'm not sure but if my memory is not too bad I think your VFD has a 12V output :)
So you could just wire the Tachometer to the VFD 12V output and that should be fine.
I use a Mitsubishi VFD that has several of those 12V outputs which is really handy.
its 10v dc
since the tachometer is 8 to 12V this seems to be just fine :)
I just finished powering it with an old phone power source 9v. Works well.
You could use a push button that only displays rpms while button is pushed
Pete
find and use a 120 volt dc miniature transformer from an intendo/electric razor miniature radio or game device.
wire it up with 120 volt and use secondary for your digital read out. go to a pawn shop or similar they will have boxes of small 20volt/12-24volt xformers.
david
Your V.F.D. may have a DC output for your digital display. I had seen on the out side of your V.F.D. a label marked DC that may for a DC motor. You need to check the manual.
Thank you for the tack. tip on ebay. What you will now need from Radio Schack
Is a small and cheap relay normally open. Wired into the 110 machine switch &
one 9vt wire is cut >that goes to the little relay. machine turned on - relay closes
and the tack. is energized. Simple & cheap
sam
Frequency is inversely proportional to the amperage, which relates to the motor torque.
You might have an option on your inverter to input the hall effect sensor for feedback/speed. Check to see if your inverter has a 10vdc output, that can power your display.
I just finished powering it with an old phone power source 9v. Works well.
great, i did have a look in your manual to see if it had a setting to increase the torque (current) at low speed/frequency but there is no adjustment,
there is an adjustment that you can increase torque at startup which wont really help you at all really once the drive is up to speed and you hold the chuck it will still stall :(
maby a 3 or 4 hp inverter wont stall at low speeds
or maby change the motor to a smaller hp rated motor that will help, for sure
To my experience with VFD, you shouldn' be going under -50 % and over +50 % of motor (AC) speed. Under you lose torque and cooling, and over it could overheat also. Wasn't this mentioned in the manual ?
Like your video's, all the best.
Greetings from Belgium,
Ludo
Your vfd should have +12v supply in it, you could wire the tach to the vfd and it would switch on and off with the unit.
There are three options: use 9v rechargeable batteries. You can get am with AA battery holder that has a 9v connector. The 1.5v AA will be less expensive and you can us nicad rechargeable batteries. Finally use a 9v or 12v wall adapter. Pick up one of the arduino power adapters...
So we could use a wall wart and provide 9 to 12 volts for the tach.