Re: VFD tachometer sanity check

Jim:

Yes. I was figuring on using the max RPM reading (on a voltmeter)
to be calibrated to 10 volts analog output which is linked to the
frequency.

Jeff

--- In CAD_CAM_EDM_DRO@yahoogroups.com, "James Cullins"
<jcullins@c...> wrote:

> Jeff
> I have been thinking about that myself. Wouldn't you need a way

to set up

> the max RPM
> to indicate the RPM correctly?
> Thanks
> Jim
> ----- Original Message -----
> From: "washcomp" <jeff@w...>
> To: <CAD_CAM_EDM_DRO@yahoogroups.com>
> Sent: Saturday, November 22, 2003 7:40 AM
> Subject: [CAD_CAM_EDM_DRO] VFD tachometer sanity check
>
>
> >
> > I'm thinking of buying a variable frequency drive for my

Bridgeport.

> >
> > The 10 Volts off the analog contacts of the VFD can be set to be
> > proportional to the frequency.
> >
> > If the RPM is linear to the frequency (after slip has been taken
> > into account), and if the voltage is linear to the frequency,

then

> > shouldn't the voltage be linear to the speed?
> >
> > If this is the case (the real question I'm asking), once the

setup

> > is calibrated, this should give the ability to have an accurate
> > electronic analog tachometer on the control pendant I'm designing
> > without resorting to an additional optical encoder.
> >
> > I figure a tachometer would be useful for "manual" machining and
> > sanity checks on CNC milling.
> >
> > Any thoughts, comments or suggestions would be appreciated.
> >
> > Jeff
> >
> >
> >
> >
> >
> >
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