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Thread: Is there a JoeWoodworker for VFD drives?

  1. #16
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    Quote Originally Posted by Malcolm McLeod View Post
    ...Bottom line is it may be tough to find a 3-ph motor to match the 1-ph.
    On my drill press (a Delta about ten years old) the OEM motor seems to be a nema 56 size, although the shaft is 17 mm.

  2. #17
    Quote Originally Posted by Jamie Buxton View Post
    On my drill press (a Delta about ten years old) the OEM motor seems to be a nema 56 size, although the shaft is 17 mm.
    This is what I was alluding to - - the NEMA standard for a 56-frame is a 5/8" diameter shaft. (It's the same for all '56/56C/56H/56J frame' motors; 56HZ is 7/8 diameter.) The good news is that you can get a 3-phase, 230V Baldor in 56-frame in a number of ratings from 1/4 to 2 Hp; the bad news is that your drive sheave won't fit. Again, I think the manufacturers play pretty fast and loose with the frame specs in these small sizes - - evidenced by your 17mm shaft.

    I didn't search other motor manufacturers, but you might get lucky and find the right combo there....?

    Edit: I also suspect this 'elastic specification' holds true in the IEC frame sizes, but if you're not afraid of a few metric<>imperial conversions, this might be a good search option as well.
    Last edited by Malcolm McLeod; 02-08-2017 at 2:10 PM.

  3. #18
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    Thanks to all. The package Jamie suggested appears to be a perfect fit. Same motor frame. So I just ordered it.
    wish me luck.

  4. #19
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    ok guys, I followed Jamies advice and got the package from dealers electric.
    http://dealerselectric.com/three-qua...ut-Package.asp
    I find the wiring kind of intimidating.
    3 phase drillpress motor2.jpg

    I'm just replacing the single phase 3/4h motor on my drill press and I don't want to change pulleys all the time. The manual on the drive seemed fairly straightforward. I have that all hooked up. What I don't know is which of these 4 configurations to use.

    1. Am I low voltage or high voltage? The driver manual seems to suggest that I'm low.
    2. Which configuration do I want: Delta or Y?

  5. #20
    Quote Originally Posted by Roger Feeley View Post
    ok guys, I followed Jamies advice and got the package from dealers electric.
    http://dealerselectric.com/three-qua...ut-Package.asp
    I find the wiring kind of intimidating.
    3 phase drillpress motor2.jpg

    I'm just replacing the single phase 3/4h motor on my drill press and I don't want to change pulleys all the time. The manual on the drive seemed fairly straightforward. I have that all hooked up. What I don't know is which of these 4 configurations to use.

    1. Am I low voltage or high voltage? The driver manual seems to suggest that I'm low.
    2. Which configuration do I want: Delta or Y?
    1. This low/high is referenced to the motor. Look at the name plate - it probably reads "Voltage 240/480VAC", and of course means the motor can operate on either. As this relates to your install, it means you would supply 240VAC/1-ph to the drive, the drive supplies 240VAC/3-ph to the motor, and the motor is wired using the 'low' diagram (because 240VAC is the low option on the nameplate).

    IF motor nameplate reads "120/240 VAC", then (I assume) you will still supply 240VAC/1-ph to the drive, the drive supplies 240VAC/3-ph to the motor, and the motor is wired using the 'high' diagram (because 240VAC is the high option on the nameplate).

    2. I'll have to let one of the smart guys answer this.

  6. #21
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    Thanks for the links. I just ordered a Teco from one of the links for my Clausing. It is a two speed motor with reeves drive so I do not really need the variable speed part, but just wanted to be able to drill holes with out having to start the 50hp phase converter. I will have to shut the VFD off to change motor speeds, but how often would one do that in one operation, especially with a Reeves drive.

    My only question would be what would happen if someone started the VFD with the motor speed selector in the off position? Not worried about me, but I do hire help occasionally. Would it do nothing, or would it damage the VFD?

    I think I may make it a plug in affair so I can switch back to the converter easily If the VFD takes a dump.

  7. #22
    Quote Originally Posted by Larry Edgerton View Post
    ... what would happen if someone started the VFD with the motor speed selector in the off position?
    ...
    The thing most likely to cause damage would be starting the VFD, and then switching the speed selector 'on' (or switching speeds via the selector). The VFD 'sees' the load go to/from zero to full. This wreaks havoc with the DC bus voltage.

    Safest bet would be to interlock the speed selector to the VFD via a spare contact block in the speed selector switch. You may have it already, or can add it? If so, make sure the spare contacts are 'closed' when speed select is 'on' ('open' if select is 'off'). Then wire this contact back to the VFD as a run permissive, stop, or e-stop signal. If the selector switch is changed on the fly, it should immediately stop the VFD.

  8. #23
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    I'm at the point where I need to dismount the sheave (new word!) and test mount it on the new motor. I got the motor running last night (thanks to some helpful PMs from Jamie). If it doesn't fit, I will try to find something online. I think I'm at a point where the rest ought to be doable.

  9. #24
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    Quote Originally Posted by Malcolm McLeod View Post
    The thing most likely to cause damage would be starting the VFD, and then switching the speed selector 'on' (or switching speeds via the selector). The VFD 'sees' the load go to/from zero to full. This wreaks havoc with the DC bus voltage.

    Safest bet would be to interlock the speed selector to the VFD via a spare contact block in the speed selector switch. You may have it already, or can add it? If so, make sure the spare contacts are 'closed' when speed select is 'on' ('open' if select is 'off'). Then wire this contact back to the VFD as a run permissive, stop, or e-stop signal. If the selector switch is changed on the fly, it should immediately stop the VFD.
    OK, I pulled the drum switch out, and although I understand what you are talking about in principal, ya, that is way to much wiring for my limited knowledge. So.... another question

    I want to leave the drum switch where it is for use as an emergency shutoff, much more convenient in the case of a drilling emergency than a keypad. I know I can not turn on the load and not damage the VFD, but would suddenly interrupting the load on that rare occasion cause harm? Assuming that 99.999% of the time it would be shut off with the VFD control panel.

  10. #25
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    Again, thanks to all. Last weekend, I removed the old motor and installed the new one. I wired up the original switch to be an external run/stop switch for the controller and that works fine. So I can use the original switch to turn it on and off and the original light switch still does it's thing.

    I'm a bit concerned that there is a ventilation fan on the controller. Won't that get dusty? I mounted the controller on the wall next to the drill press.

    The only thing left to do is to take the step pulley back off the motor and take it to have a keyway cut. There's a local machine shop that will cut the keyway for $50. I figure that's better than going out and trying to hunt for a duplicate step pulley. I did some searching and didn't find much.

    Again, thanks to all for the good advice.

  11. #26
    Are you purposely keeping the step pulley on the motor? You could probably buy a new single sheave with the right bore and keyway for ~$10 from McMaster, and avoid having to have a keyway cut in your step pulley.

    Now that I think about it: how was it held to the old motor?

  12. #27
    Quote Originally Posted by Larry Edgerton View Post
    OK, I pulled the drum switch out, and although I understand what you are talking about in principal, ya, that is way to much wiring for my limited knowledge. So.... another question

    I want to leave the drum switch where it is for use as an emergency shutoff, much more convenient in the case of a drilling emergency than a keypad. I know I can not turn on the load and not damage the VFD, but would suddenly interrupting the load on that rare occasion cause harm? Assuming that 99.999% of the time it would be shut off with the VFD control panel.
    Larry, sorry for the lag. This thread sort of fell off my radar.

    You can probably use the drum switch to open the circuit from the VFD to the motor and not do any damage. Most of the time ...but I'd hate to have give odds on this never causing any damage.

    The real risk is on closing the drum switch. For example, in sequence: #1 The drum switch is closed and VFD is OFF. #2 You start the VFD, tool ramp up to the preset speed. #3 You have a problem and stop the machine by opening the drum switch. #4 Quickly correct the problem and close the drum switch. #5 VFD output bus never powered down and is now hit with full load of machine starting. This 'shock load' is what is most likely to damage a VFD. You can avoid it by inserting a step "#3b - Stop the VFD via keypad", the only question is will you remember to do so - - every single time.

    A much safer method is to use the same drum switch, but wired as an e-stop, feeding back to the IO terminals on the VFD. (VFD output is wired direct to motor.) You can then 'open' the drum switch when a problem occurs, the VFD sees the 'stop command', decelerates the machine, and is ready to start again. No damage.

  13. #28
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    Quote Originally Posted by Malcolm McLeod View Post
    Larry, sorry for the lag. This thread sort of fell off my radar.

    You can probably use the drum switch to open the circuit from the VFD to the motor and not do any damage. Most of the time ...but I'd hate to have give odds on this never causing any damage.

    The real risk is on closing the drum switch. For example, in sequence: #1 The drum switch is closed and VFD is OFF. #2 You start the VFD, tool ramp up to the preset speed. #3 You have a problem and stop the machine by opening the drum switch. #4 Quickly correct the problem and close the drum switch. #5 VFD output bus never powered down and is now hit with full load of machine starting. This 'shock load' is what is most likely to damage a VFD. You can avoid it by inserting a step "#3b - Stop the VFD via keypad", the only question is will you remember to do so - - every single time.

    A much safer method is to use the same drum switch, but wired as an e-stop, feeding back to the IO terminals on the VFD. (VFD output is wired direct to motor.) You can then 'open' the drum switch when a problem occurs, the VFD sees the 'stop command', decelerates the machine, and is ready to start again. No damage.
    For what it's worth, my VFD has terminals for an external run/stop switch. I re-tasked the original switch on my drill press to be that external switch and it works great. I still use the switch I've used for the last 35 years. The only reason to touch the VFD is to change speeds.

    I could put an external potentiometer to control speed as well and I might do that. The original trigger for this whole enterprise was that the original motor was making a weird buzzing noise (capacitor?) so I decided to upgrade. It turns out that the VFD isn't silent and I might like to stick that in a box or something. So an external pot might be in my future.

    Also, I note that the VFD has a ventilation fan. That give me some concern about dust. Maybe a dustproof box would be a good idea.

  14. #29
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    The motor is in but now I'm having torque problems. I was drilling some 7/32" in some angle iron and the motor stalled just as the bit was breaking through. Then I went to countersink the holes and I had to be super careful or it would stall. I checked to make sure the pulleys were tight. It's the motor.

    The ratio on the pulleys is just about 1:1. So this is the equivilant of mounting a 7/32" bit on the end of the motor shaft.

    There's stuff in the VFD manual about torque compensation but it's written for people who do this for a living. Any advice?

    Here's the link to the manual at Dealers Electric.
    http://www.dealerselectric.com/images/Products/teco/L510instructionmanual.pdf




  15. #30
    Quote Originally Posted by Roger Feeley View Post
    The motor is in but now I'm having torque problems. I was drilling some 7/32" in some angle iron and the motor stalled just as the bit was breaking through. Then I went to countersink the holes and I had to be super careful or it would stall. I checked to make sure the pulleys were tight. It's the motor.

    The ratio on the pulleys is just about 1:1. So this is the equivilant of mounting a 7/32" bit on the end of the motor shaft.

    There's stuff in the VFD manual about torque compensation but it's written for people who do this for a living. Any advice?

    Here's the link to the manual at Dealers Electric.
    http://www.dealerselectric.com/images/Products/teco/L510instructionmanual.pdf



    See page 8-3 in the manual. Follow the directions to set parameter 01-10. Default is 0.0, and I'd recommend you set it to 1.0, then test:
    1-Set your display to show instantaneous current, and retry your drilling operation on a sample.
    2-Monitor the amps displayed to make sure you aren't exceeding the drive's max current limit while drilling.
    3-Adjust 01-10 up if the drive stalls, or down if the current is excessive.
    4-Repeat until you're happy with the test result.

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