Re: VFD drive problems with older 3-phase motors (correction)

Ted, how was the motor originally connected to the contactors? How
could you possibly determine wye/delta from ohm-meter measurements
when wye and delta circuits are electrically equivalent?

~petev

--- In CAD_CAM_EDM_DRO@yahoogroups.com, "Ted Inoue" <ted@s...> wrote:
> (correction to my previous post)
> I've heard that there may be problems using VFD drives with older
> motors, and I am indeed having problems with mine. But I'd like to
get
> input from others on their experiences.
>
> The motor I'm trying to run is a big 3HP 240v 3-phase, 2-speed
mounted
> on a Logan Lathe. It was run by the guy who sold it to me using a
> rotary converer, which I haven't tried yet, but will to see if I can
> get it going that way.
>
> For testing, I bypassed all the controls, contactors, etc. and
hooked
> the VFD directly to the motor. The motor has 6 wires which I've
tested
> with an ohm-meter and concluded that it's wired in a delta format
with
> 1-2-3 being one set of connections and 4-5-6 being another. At
least,
> that's what I'm guessing based on the measured resistances.
>
> Originally, I tried the VFD outputs to the 1-2-3 motor inputs, and
> could get the motor to respond slighly in both directions, but with
> absolutely no power. Enough to rotate about 1/2 rev.
>
> Connecting to the 4-5-6 inputs results in no movement and just a
> little whine from the motor.
>
> Is there something obvious I could be overlooking? I scoped the
> outputs and I am getting high voltage, periodic (i.e. pwm pseudo-
sine)
> outputs (with the motor connected).
>
> Thanks for your input.
> -ted
>
> p.s. merry xmas!