110V VFD for a 3/4HP motor?

[eyekode]

I was lucky enough to buy Wayne's PM 1150A today . It currently has a 3PH 3/4 HP Leeson motor on it. My options are to either replace the motor with a 110v motor, add a static phase converter or add a VFD.

Right now I am leaning toward a 115v VFD that can drive 1HP: http://www.factorymation.com/s.nl/sc.2/category.30/.f

I like this option because I can further reduce the RPM for large bits and when drilling metal. And I don't think a static phase converter would be much cheaper. I like the idea of a 115v VFD because then I could plug the thing in anywhere (although I do have plenty of 220v outlets). And if I ever replace the motor I don't think I will go over 1HP anyway (which looks to be the limit for a 115v VFD).

I am also wondering if anyone has 3-phase power around Apex that I could plug into just to be sure the motor works before I buy the VFD.

Any opinions?
Thanks!
Salem

 

[scsmith42]

Salem, I have you covered re the 3-phase. Let me know when you want to bring it out.

I like the VFD option. Regarding speed changes, see if you can find one with a knob instead of a digital keypad - it will be much more practical for a lathe.

 

[Sully]

I'm using one of those 1HP VFD's on a lathe, wired to run off 115V. I've been very happy with it. I'd vote for one without a knob on the VFD. You can wire up a potentiometer to the VFD for speed control. That option allows you to mount the potentiometer on the front of the machine for easy access and mount the VFD anywhere you want.

Easy way to check the motor is to single phase it. Take the motor off the drill press and change the power plug to a single phase 220V plug; you'll have one extra power lead, just cap it. Spin the motor shaft up to speed by hand with a pull cord or with a cordless drill and remove. Shoot single phase 220V to it and bob's your uncle; it should spin right along. You can check the other loose lead by either swapping it for one of those you just tested or by measuring the voltage of it to ground with the motor single phasing. Usual disclaimers apply: be careful!

$0.02

 

[eyekode]

Thanks Scott, I may take you up on that. But I would hate to have you fire up a 300HP generator for my 3/4 hp motor . By the way the PM1150A is a drill press with a Reeves drive. So it is already variable speed but doesn't go quite as low as I would like.
Salem

 

[eyekode]

Thanks Sully! I knew I had heard of that trick before but couldn't remember the details.
Salme

 

[scsmith42]

Thanks Scott, I may take you up on that. But I would hate to have you fire up a 300HP generator for my 3/4 hp motor . By the way the PM1150A is a drill press with a Reeves drive. So it is already variable speed but doesn't go quite as low as I would like.
Salem

Actually, the generator is 400hp but whose counting?:gar-Bi

I like Sully's idea re the potentiometer, just be sure that you purchase a VFD that allows the easy addition of one.

If you're motor is 240 3-phase, I can run it off of my phase converter (up to 30 hp), so no big deal.

 

[Alan in Little Washington]

Most definitely, keep the Reeves drive, because with the VFD you won't have power at low RPM unless you gear it that way initially. (I assume the motor is 1725 RPM.) I second the recommendation for a remote speed pot.

When I converted my Delta DP to a VFD I replaced the 3/4 hp single phase motor with a 1.5 hp 3 phase one. I also have it geared down (belt -pulley) for good low speed hp which you will lose if you try to do it with a VFD alone. I must over-speed the motor to get high drill rpms.

I added a potentiometer (red knob) and a small toggle switch for remote speed control and start/stop. (I also added a tach) The original start /stop buttons power the VFD. The front of the plastic housing on the Delta was a perfect place to mount the controls and the tach readout.

I mounted the VFD behind the headstock and below the motor.

 

[eyekode]

Very nice Alan! I would like to reuse the original controls if possible as well. Still haven't opened it up to see if that is possible (and once I open it up it will take me a while to figure it out anyway ). I will probably ask you some more Q's when my VFD gets here!
Salem

 

[eyekode]

I ended up ordering my VFD from factorymation.com. It shipped promptly and arrived quickly with good packing. I wired it as simple as possible with 115v to the l1/l2 connectors, ground to ground and T1/T2/T3 to the motor. When I first turned it on it was at 5Hz. Not sure why they would not default to 60Hz but oh well. It spun up the motor fine. The soft start is cool.

Still have to decide where to mount the VFD and how I want to control it. I don't think I can use the stock power switch without picking up a relay. And I do think I will want a pot to control the frequency. Maybe I can fit the new controls back into the original housing? Will see.

Unfortunately the Reeves drive is not behaving well. That will be another thread .
Salem

 

[eyekode]

I solved my wiring issues last night. Turns out I had miswired the motor when going from 440 to 220v. The motor label made it look like the last three of the nine wires should be floating:

View image in gallery​

I guess my eyes are not what they used to be.

I also wired up the original switch to the low voltage input of the vfd so I can use the original switch to turn on and off the press. But the wiring leaves something to be desired:

View image in gallery​

View image in gallery​

View image in gallery​

And right now the vfd is "mounted" to the press with rare earth magnets. Any suggestions on how to attach the vfd to the press? Any suggestions on how to provide strain relief for the power inut and output in the vfd? I dont like them just hanging there...
Thanks!
Salem

 

[Alan in Little Washington]

I solved my wiring issues last night. Turns out I had miswired the motor when going from 440 to 220v. The motor label made it look like the last three of the nine wires should be floating:

Hmmm, thats what it looks like to me, too!

And right now the vfd is "mounted" to the press with rare earth magnets. Any suggestions on how to attach the vfd to the press? Any suggestions on how to provide strain relief for the power inut and output in the vfd? I dont like them just hanging there...
Thanks!
Salem

I would attach the VFD to some sheet metal or brackets mounted between the motor base and the mounting plate where it would be held in place by the motor mounting bolts.

Run the low voltage control wires through the headstock or belt/Reeves housing to the switch and replace the switch plate so you can could attach a different switch and a speed pot- plenty of room for both.

 

[eyekode]

Hmmm, thats what it looks like to me, too!

I puzzled over this when I wired it the first time. I could not figure out how letting these 3 wires float worked? Maybe they were the center taps for the coils? But that didn't make sense from the other connections. After I stalled the motor I finally looked closer at the wiring and there are teeny tiny solder dots between the three circles. Doh!

I would attach the VFD to some sheet metal or brackets mounted between the motor base and the mounting plate where it would be held in place by the motor mounting bolts.

Run the low voltage control wires through the headstock or belt/Reeves housing to the switch and replace the switch plate so you can could attach a different switch and a speed pot- plenty of room for both.

I like the idea of using the motor mounting bracket screws to hold a mounting plate. But do you provide any strain relief for the power connections on the VFD?

Also not sure if I can run the low voltage wires through the headstock. I have them running out of the hole where the original high voltage lines went. I will have to look closer.

Thanks again Alan! Couldn't have gotten this far without the help from the forum!
Salem

 

[Alan in Little Washington]

I like the idea of using the motor mounting bracket screws to hold a mounting plate. But do you provide any strain relief for the power connections on the VFD?

My VFD has a larger housing and cable clamps. You can add some sort of clamp if you use a mounting plate that extends below the VFD where the wires come out.

Also not sure if I can run the low voltage wires through the headstock. I have them running out of the hole where the original high voltage lines went. I will have to look closer.

If one isn't there already, you might be able to drill a hole for the wires from the belt/Reeves housing just above the switch bumpout.