Re: dc spindle motor control.

The third wire I refer to is directly off the brush wiring, and must
be from about the center of that circut. There must be a way to
control this motor, It is a factory fanuc spindle motor. Would
decrasing the field current still increase the motor speed?

--- In CAD_CAM_EDM_DRO@yahoogroups.com, Jon Elson <elson@p...> wrote:
> Andrey Lipavsky wrote:
>
> >On a side note... My understanding is that, in general, it's a
real bad idea
> >to regulate an inductive load, such as a motor, with any kind of
resistance,
> >such as a rheostat. Is that still the prevailing logic?
> >
> >
> No, I have no idea how you got that notion. I'm not sure what it
is
> that could
> be a "bad idea". A large inductance in series with a large
resistance
> can take
> a long time for the current to reach its steady-state value, so it
would
> be bad
> for anything that needs to respond quickly. That's why the old L/R
> stepper drives
> are such poor performers. Of course, it is also quite inefficient,
> which is why
> the OP was talking about a 500 watt (!) rheostat.
>
> Jon