Re: [CAD_CAM_EDM_DRO] high frequency spindle motors

>
>Induction motors have what is called a volts/Hz curve, which is very
>nearly a straight line.
>So, at 167 Hz, you apply 50 V, and at double that, 334 Hz, you apply 100
>V. Four times
>that is 667 Hz (accounting for a roundoff) and 200 V.

Thanks Jon,

I looked in the manual for one of the VFDs I'm already using and found this
reference. It seems the v/Hz curve can even be customized at a couple of
levels if needed. All makes sense now...

>AC tech has a mid-size VFD that goes to 1000 Hz,, that is their MC1000
>series. The 1000 Hz

I'm getting a price from ACTech on a 1000hz unit. May as well use the full
speed potential if it's not too 'spensive. If the AC Tech price is too
high, I'll drop to a 400hz unit from Automation Direct.(~190 clams)

>With all of these units, you will probably need series inductors on the
>3 lines between VFD and
>motor. I used 1.6 mH with my Westwind spindle. That would at least be
>close for your application.

What exactly do the output inductors do? Where do you get chokes that will
handle the current? Is a 1.5mH line reactor going to satisfy the same needs?

-Bob