RE: 1/4 HP sync motor power

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Terry Fritz" <twftesla-at-qwest-dot-net>

Hi Richard,

In the picture:

<http://hot-streamer-dot-com/temp/4thHPsync.gif>http://hot-streamer-dot-com/temp/4t
hHPsync.gif

The top yellow trace is the AC input voltage to the motor with a TEK 5100
voltage probe.

The center blue trace is the motor current read with a Pearson 411 current
monitor.

The lower red trace is the instantaneous voltage and current multiplied
together to get the instantaneous power trace in red.  So the red trace is the
instantaneous power that you want.  It is interesting to note that the power
waveform is at 240Hz

The scope can add subtract multiply or divide the values of the first two
traces to get the red trace.  The scope "knows" that these will be un units of
watts or ohms depending on the other settings.

The yellow and blue readouts to the left are the RMS values of the voltage and
current waveforms and the red readout is the mean of the instantaneous power
trace.

Cheers,

        Terry


At 09:48 AM 7/29/2001 -0400, you wrote: 
>
> Terry,
>  
> Great scope picture.  I assume this is your Tektronix digital storage scope. 
> I have the TDS 210 with the monochrome display.  Your math function is a
> mean?  Does you scope have a multiplication function?  Would be nice to have
> it to display instantaneous power.
>  
> RWW