vfd with old motor

A VFD should work, but the wave form of the power coming out of a VFD might tax an older moter more than a new motor designed for VFD service. Those old motors usually had more beef to them and will probably be fine. The net result would be overheating in a fully loaded continuous operating motor. A table saw is neither fully loaded, nor continuous.

-- Michael :-{| Diapers and politicians both need to be changed often; and for the same reason.

”Are they something I can use with a motor this old ”
If it is three phase, yes. Many VFDs will also give you speed control.
Just be sure you are talking with the technical people about your motor with the VFD company.
Never hurts to buy a little larger than necessary.

-- When the moderator chooses sides, his site sucks.

There are quite a few people at the OWWM.org forum that have put VFD’s on motors of the age and older. They do not seem to have any problems. If you have any questions the folks over there can probably answer them easily in the electrical section of their forum.

My guess would be a 50/50 chance of a VFD working with that old motor. The problem is the insulation and the high frequency switching the modern VFDs use to make the 3 phase. An older style VFD from about 20 years ago would be a better bet. I would suggest checking the motor with a high megger or megaohm meter. If it doesn’t read infinity, you will definitely be better off using a roto phase.

If you hook it up to a drive, it probably won’t hurt the motor. If it the VFD doesn’t start motor it is because it is seeing ground fault through the old insulation even though the motor will run fine on normal power.

-- "some old things are lovely, warm still with life ... of the forgotten men who made them." - D.H. Lawrence Wake Up America!! Please read; http://www.commondreams.org/view/2009/01/26-0

I think I am going to go ahead and buy A VFD. Thanks for everyone’s help