Re: [CAD_CAM_EDM_DRO] Strange motor - question

Jerry Kimberlin wrote:

> wanliker@... wrote:
> >
> > There are some small motors with two windings connected in series used as
> > control,reversable motors. There is a capacitor connected between the two
> > ends of the windings. The power is applied to the centertap, and one end
> > connection, and the morot will run one direction. If the power is applied to
> > the other end connection, it will run the opposite direction. I missed the
> > start of this thread, is there a possibility that this is what you have
> > instead of a three phase?
>
> Hi Bill, even though there is only a partial nameplate, it clearly
> states 60 cycle, 3 phase. I think I've found out that it is 120 vac
> rather than 230 vac, however. That explains the error messages on
> the SJ100 VFD. I call up a fellow at Fincor and found that their
> VFDs can be teased into putting out 120 vac 3 phase by going to
> constant torque mode of operation. There you set the max frequency
> at 120 instead of 60 hz and have the motor operate at 50%. Since I
> don't have a Fincor, I'm not sure what that means. I'm looking into
> reprogramming my SJ100 to operate in constant torque mode, etc. etc.
> to see what happens.

My Magnetek GPD333 VFD can be set for any voltage at max frequency.
So, if you had a 120 V, 60 Hz motor, and wanted to run it only up to
60 Hz, you'd set the max F at 60, and the max V at 120, and it would do
all the calculations. If you wanted to run it in constant power above 60
Hz, you could set it for 120 V and 120 Hz, with constant power starting
at 60 Hz, and it would ramp voltage up to 120 V at 60 Hz, and then stay
at 120 v above 60 Hz. (If the windings could take it, you could also
set it to go up to 240 v at 120 Hz.) If your VFD is one of the later
models, it likely can do this, too.

Jon