Re: [CAD_CAM_EDM_DRO] Re: Les Newell servo current and voltage

The current readings may not be accurate, since the current waveform in the
transformer is unlikely to be a sin wave.

Most filters are capacitor input, which means that current is only flowing
when the transformer output voltage is higher than the capacitor
voltage. This creates what amounts to odd-harmonic distortion, or a
frequency spectra that is heavy on (in the US) 180, 300, and 420 Hz
energy. How the clamp-on ammeter responds to this is unknown.

Still, you should get good comparison readings. Maybe you could calibrate
the readings by using a known load.

-- Carl


At 02:03 AM 2/12/2005 +0000, you wrote:

>Well i would be just as happy with an AC current reading from one of
>the transformer wires on the secondary.
>
>
>Wally
>
>
>--- In CAD_CAM_EDM_DRO@yahoogroups.com, Jon Elson <elson@p...> wrote:
> > cnc_4_me wrote:
> >
> > >By any chance do you have a clamp on ampmeter...Would be
>interesting
> > >to find out how much current is being used with your 3 axis test
>you
> > >did the other day...
> > >
> > >
> > Very few clamp-on ammeters will measure DC. They are calibrated for
> > 50-60 Hz sine waves, only. There are some current probes with hall-
>effect
> > devices in them, but they are very expensive.
> >
> > Jon
>
>
>
>
>
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