Re: Variable frequency drive question

--- In CAD_CAM_EDM_DRO@yahoogroups.com, "Hugh Prescott"
<hugh345@a...> wrote:

> Aggreed with the exception that some/all VFDs have a mim motor

impedance

> limit below which unsatificatory operation or damage to the VFD can

result.

>
> The work around is to add inductors in the motor leads which

efectivly

> derates the motor.
>
> I also understand the difference between factory design engineering

and

> field engineering <GRIN>
> Hugh

Oh, and a BIG caution. NEVER - EVER switch a motor running on
direct line voltage back to a VSD. The sheer quantity of smoke will
make one think Genie will appear.


But, this may be a moot point anyway as most of us home brew type are
running single phase to the VSD and a 3 phase motor. And for that,
you cannot switch to line voltage.

Dave

>
>
>
> > Check the VFD's current rating. you can run a motor 'up to' that
> > rating.
> >
> > I have used many, many 20hp drives to run 30hp motors up to about

80%

> > of the rating of the DRIVE (not the motor) and then for full

speed,

> > switched over to directly to line voltage. Think of it as a soft
> > start with low speed capablities.
> >