Question about VFD for Powermatic 1150A drill press

[ryanjg117]

I have in my possession a really nice looking, older Powermatic 1150A with the speed adjustment knob at the top. Came with a 1hp, 3ph Baldor motor. I only have single phase 220v in the shop, so I am looking to get a variable frequency drive to run it. AutomationDirect sells a suitable drive for about $130. I plan to mount it on the side of the machine near the existing contactor box.

Just a few questions:

1. Is there any power loss when using a VFD in this manner? What are the drawbacks?

2. I understand I can manipulate motor speed via the VFD knob. However, this drill press already includes the ability to change speeds (while running) using the knob at the top of the drill press. Should I just set this VFD to 100% all of the time, or can I achieve even more granular speed adjustment via the drill press knob + VDF switch?

3. This drill press was missing it's power switch as well. I assume a standard 220v 30a double pole switch like this one would suffice?

I'm considering a couple different drives:

Teco Variable Frequency Drive

AutomationDirect GS1-21P0 MicroDrive

Any thoughts or opinions on either?

 

[polarsea1]

That switch is motor rated so it will work. Setting the motor speed at 100% would be the best solution since VFDs work best (most efficiently) with motors that are build for that application.

 

[Bob D.]

I was thinking it might have had a contactor not just a simple switch but looking at this YT video it appears that a switch is all it had.

 

[rvieceli]

[member=51886]ryanjg117[/member] No switches between the VFD and the motor. You’ll use low voltage controls on the VFD to ramp the juice up. If the current switch is a locking on/off you can use it. I use one off these on my stuff.
https://www.amazon.com/POWERTEC-710...h/dp/B00KPEFL2I/ref=mp_s_a_1_4?keywords=power+tool+switch&qid=1563019527&s=gateway&sr=8-4

You’re only running 12volts through it.

I use and like the Teco VFDs.

Holler if you have any questions.

Ron

 

[ryanjg117]

So, would I be fixing the drill press knob to it's full speed (4500 rpm) and then adjusting the actual speed in use via the VFD?

A gentlemen on Craigslist looking to sell a 2hp drive noted this about 1hp drives:

The drive you are talking about is too week for your 1 HP motor.
If it was a fan, you could assume that the desired and delivered powers should be equal. However in drilling presses very often a large drill bit (over 1/2") gets stuck causing complete "freezing". That causes the amperage spike and could lead to VFD toasting. Another complexity - a sophisticated programming of the drive according to your application.
The last challenge - a very few options in case it doesn't work at all.

Clearly ESL there. Probably some hyperbole there but just curious of his comment on oversizing the VFD has any merit.

 

[rvieceli]

That particular press has a Reeves drive that is used to vary the speed of the quill. Turning the knob varies the pitch of the pulley sheaves  to change the effective length of the drive belt.

I have 2HP 3 phase motors on my band saw and my table saw being run by 2HP Teco VFDs. On mine (and I would probably suggest setting yours the same way) all the VFD does is supply the 3 phase at 60 Hz. I have programmed the VFD to take a few seconds to ramp up to the full speed. kind of gives it a soft start.

The VFD also has some low voltage terminals that can control the VFD. one of those inputs is a start/stop input. supply current from one of the other lv terminals on the VFD and the VFD starts up and keeps going until the current is removed. That's what the switch I linked gets connected to.

In your case, you would set up the VFD to get up to speed (60Hz) and then use a simple start stop switch to turn it on. You would use the Drive speed control on the drill press to control the quill speed. You would be using the drill press the way it was designed to be used.

If you did not have the variable drive model you would use the VFD to control the quill speed. Simplifying it, the lower the frequency to the motor the slower the speed and the higher the frequency the higher the speed. 3 phase industrial motors are usually fairly robust and can take the over driving. There can be some concerns with under driving the motor. The concern being that the motor is designed to operate at full speed and at lower speed the fan in the motor won't adequately cool it allowing the windings to overheat.

I believe that the slowest that model will go is 475 rpm. If you are going to be drilling a lot of bigger holes in steel, you might benefit from using the VFD to slow the quill down. Other than that for woodworking operations using the variable speed on the press you should be fine.

Ron

 

[rvieceli]

I get my VFDs from these folks. They have been very helpful.
https://www.factorymation.com/

You can enlist their help in sizing your VFD through their online chat. They carry the full TECO line.

Ron

 

[rvieceli]

One other thing, as I mentioned earlier, you don't want a switch between the VFD and the motor. apparently that's a good way to kill the VFD. so the power leads go direct from the VFD to the motor. You use the LV terminals on the VFD and a locking on off switch (connects the current until you turn it off) to turn the equipment on/off.

 

[ryanjg117]

One other thing, as I mentioned earlier, you don't want a switch between the VFD and the motor. apparently that's a good way to kill the VFD. so the power leads go direct from the VFD to the motor. You use the LV terminals on the VFD and a locking on off switch (connects the current until you turn it off) to turn the equipment on/off.

Thanks, but still a bit confused as you mentioned a 12v switch but then linked to a 120v switch on Amazon?

Incoming power goes to the VFD and then to the motor. A switch will come off the VDF, correct?

 

[rvieceli]

One other thing, as I mentioned earlier, you don't want a switch between the VFD and the motor. apparently that's a good way to kill the VFD. so the power leads go direct from the VFD to the motor. You use the LV terminals on the VFD and a locking on off switch (connects the current until you turn it off) to turn the equipment on/off.

Thanks, but still a bit confused as you mentioned a 12v switch but then linked to a 120v switch on Amazon?

Incoming power goes to the VFD and then to the motor. A switch will come off the VDF, correct?

A switch is a switch as long as it will take the amps generated.  [big grin] you probably could use the switch already on the press if it stays on when you turn it on.

I use that switch because it looks like something that would be there usually and it works and fits the box available. And I have the VFDs set up for a remote control circuit rather than using the built in controls on the VFD. My VFDSs are in enclosure to keep them out of the way and relatively dust free.

in your application you could fashion a bracket and mount the VFD where it was accessible and use the front controls on the VFD to control the press. The problem is that the cheaper VFD is rated IP20 so it means that you can't stick you finger in it but just about everything on the planet that is smaller than the end on your finger can get in. That's potentially a lot of dust in a workshop. In addition the switches on the front of the VFD are membrane switches so they may wear out at some point.

 

[polarsea1]

"A switch is a switch as long as it will take the amps generated.  [big grin] you probably could use the switch already on the press if it stays on when you turn it on...…………."

Simply not true, do a little calc on the power throughput for 12V versus 120V using the same amperage, that's not even taking into account the different requirements for insulation, etc.

 

[gnlman]

Hi. Hmmm this thread has me thinking about the switch I used.....
I have the same teco 510 vfd as the OP is talking about. I am using a 1 hp motor with it, and also running my power into the drill press using the factory switch (rated for 15 amps)
I did this a couple years ago, so my memory of it all might be a bit off....
I replaced the existing 3/4 HP motor with a 1 HP 3 Phase as was suggested in some of the reading I did. Original motor was rated at 12 amps for 110volts, 6 amps for 220volts.
So far no issues with the VFD, but it sees light use. I have drilled 2.5 holes with a forstner bit, and used a 4 inch hole saw on the press.
IIRC the switch was rated 15 amps....(I"m going to re check that....)
I decided to use it as a safety stop in the first place due to the large paddle....not sure that was a great idea....

If you decide to do this to your powermatic, have fun with it, what a great improvement. The manual is pretty small, great for reading in bed ect....I downloaded and printed the manual as I found it easier to read in the shop, and lots of room to write notes as I tested different settings out. Hook it up on the bench first and play with it til you get it to start and stop without issues....it's easier that standing in front of the drill press...lol
Greg

 

[rvieceli]

"A switch is a switch as long as it will take the amps generated.  [big grin] you probably could use the switch already on the press if it stays on when you turn it on...…………."

Simply not true, do a little calc on the power throughput for 12V versus 120V using the same amperage, that's not even taking into account the different requirements for insulation, etc.

OK you got me what I meant was there shouldn't be a problem using a 120 volt rated switch on 10 or 12 volts

 

[rmwarren]

So I'm really dense when it comes to electrical current. Like, bobby pin in the socket kind of dense.  [doh]

Is it possible to run any 3 phase motor on one of the commonly available VFD, sized for the HP required of course?

For example, I have an old 1/2 HP Rockwell benchtop drill press that I'd like to add variable speed to. I can pick up a cheap 1HP motor @ Surplus Center for $70. A TECO L510 is around $160. Together they'd be a great upgrade.

Any reason whatever random 3 Phase motor I can get wouldn't work with some VFD? The reason I ask is for years I was under the impression that the only way to use surplus 3 phase equipment I could get cheap at auction would be to re-motor it. I'm past the stage of buying old industrial equipment (no space anymore) but I guess I'm still operating under that old impression.

Thanks,

RMW

 

[rvieceli]

Richard with my limited knowledge I think the short answer to your question is no on any 3 phase motor with a VFD. My understanding is that for a 5HP and under 3 phase motor, a VFD solution can be had. But from my research the sweet spot is really 3HP and under. The VFDs are reasonably priced.

Above 5HP and the drives get expensive and then a rotary phase converter makes more sense power and cost wise. Or swapping the motor may be cheaper.

You also need 240 single phase input and the actual 3 phase motor needs to run on 208/230 three phase (3 phase low) not 460/480

More than one or two machines and a RPC may make more sense. the VFD is not the only thing you need. The cheap VFDs are IP20 you really need an enclosure or to buy an IP65 unit which usually at least double the price or more. You also need some over current protection between your power and the VFD and maybe a machine local disconnect.

I'm running a 1974 Powermatic 20 inch band saw with a 2 HP 3 phase motor from a TECO VFD and a 1969 Powermatic PM66 Table saw with a 2 HP 3 Phase motor with another TECO unit. Both work flawlessly and are wonderful pieces of equipment.

Ron

 

[rvieceli]

Here's a link to a thread over at garagejournal that has a bunch of info and examples of VFD conversions.
https://www.garagejournal.com/forum/showthread.php?t=320064

Ron