[in2steam]

I through some fortune picked up a old atlas/craftsman (1938) drill press this weekend, with a 110/220 single phase induction-repulsion motor on it. I did not know that it was, the owner described to me what they thought was a three phase motor, although they had never bothered to look at the plug which was wired for 110 so I picked up a VFD also. At anyrate I had a thought about hooking up a VFD to see what it would do, my understanding of IR motors is a little limited, they pre-date anything I did at Leeson, for that matter they pre-date Leeson. I "think" it might work, just looking for a more informed opionion, my major concern is the fact that the brush will arc some from comutation, my understanding of that is the lower the freq the less that happens, but that would somewhat simulate breaking open the circuit which has always been a bad thing to do. Of course the winding on the stator is still in so the circuit is not really broken its just changing draw/impendance slightly. I know that the newer hybrid cars are using IR motors of some sort even though they are poly-phase I would assume they would have the same problem or not. It does not have any switch, I have not taken it apart as of yet so I don't know if the brushes adjust, although from what I understand that was pretty much the norm to get different speeds and rotation. And of course I am not completly sure what the HP is either, nor RPMS/poles as its painted black no markings.

I did play with a PSC motor not that long ago but was not thrilled with the results as it was basicaly useless below 1000 rpm, this drive will output single phase. Mainly wondering if anyone has tried this or heard of anything like it.

chris

[Al_The_Man]

Personally I think you may be 'flogging a dead horse' I think you may run across the common problems with trying to control 1ph motors by VFD.
I would think alot depends on what point the motor is designed to transition over to squirrel cage induction.
The fact that you could be moving in and out of repulsion/induction at different points of the rpm scale may prove to be an issue, you have the VFD already so It would not cost much at this point to try it while monitoring the result closely.
Unless you want to keep in its antique state, I would have thought the best bet would have been to put a 3ph motor on, or one of these higher quality DC treadmill motors available you can get really good KB DC 4 quadrant controllers on ebay for ¢ on the $.
Al.

[in2steam]

Yeah, you are kind of echoing my feelings, I do have a 3 phase motor upon further review of my stock that I could through on there, but I would like to keep the drill press near to its original(or as i found it). Its not the motor that came with it, as it about 2 sizes to big for the mount. My other worry is I don't know anything about the IR motor, maybe I will just through that on my Atlas shaper or mill. Actually I also have a 90vdc motor that I had set aside for the lathe, maybe I will switch them around, I guess I will have to think about it for awhile.

chris