Re: VFD problems with my Bridgeport CNC..

NO, NO, NO. You can't use a second VFD to power the rest of the
machine. The VFD does not generate a sine wave. It generates a square
wave output which is modulated at the carrier frequency (usually in
KHz range). The inductance on the motor smooths the output so it
averages to a sine wave. Even if you set the VFD to 60Hz, the output
is being modulated at the carrier frequency and is not a sine wave.

~petev

--- In CAD_CAM_EDM_DRO@yahoogroups.com, "Peter Reilley" <micrio@m...>
wrote:

> VFD's are terrible at handling surge loads. When driving a 3

phase motor

> you are
> supposed to connect the motor directly to the VFD without a

switch. You

> use
> the VFD to bring the motor up to speed. This is not compatible

with using

> it to power the other loads. You could use two VFD's, one for the

spindle

> motor
> and another for the rest of the machine. Obviously, the VFD

powering the

> rest of the machine would be fixed at 60Hz.
>
> Pete.
>
>
>
> ----- Original Message -----
> From: "Mike Mueller" <mueller914@y...>
> To: <CAD_CAM_EDM_DRO@yahoogroups.com>
> Sent: Saturday, March 27, 2004 11:47 PM
> Subject: [CAD_CAM_EDM_DRO] VFD problems with my Bridgeport CNC..
>
>
> > I have the feeling the FVD is "only" for the main spindle motor

and that

> it is not wise to try and power the entire machine with it???
> >
> > Am I correct here? I hooked up the VFD, turned the power on the

machine (I

> could hear only the fans run in the Boss 3 case) and the Hz LED

should on

> average of 13Hz until I turned the High/Low range knob and got an

error on

> the VFD.
> >
> > If it helps any, the VFD is a Hitachi L100-015nfu.
> >
> > Would a rotary phase converter be what i really need/want for this
> application?
> >
> > thanks......