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Re: Secondary Research (fwd)
---------- Forwarded message ----------
Date: Mon, 3 Mar 1997 08:38:03 +1200
From: Malcolm Watts <MALCOLM-at-directorate.wnp.ac.nz>
To: tesla-at-pupman-dot-com
Subject: Re: Secondary Research (fwd)
In reply....
> Date: Thu, 27 Feb 1997 15:58:20 -0800
> From: Skip Greiner <sgreiner-at-mail.wwnet-dot-com>
> To: Tesla List <mod1-at-pupman-dot-com>
> Subject: Re: Secondary Research (fwd)
>
> Tesla List wrote:
> >
> > ---------- Forwarded message ----------
> > Date: Thu, 27 Feb 1997 09:09:24 +1200
> > From: Malcolm Watts <MALCOLM-at-directorate.wnp.ac.nz>
> > To: tesla-at-pupman-dot-com
> > Subject: Secondary Research
> >
> > Hi All,
> > I still have a long way to go in this exercise, but thought a
> > preliminary finding might be of interest. It seems clear that the
> > efficiency of a number of power supplies (or use of available power)
> > leaves a lot to be desired. A reality check on one of the largest
> > systems in the survey shows that power getting to the primary all but
> > matches the measured power input. You can check your system by:
> >
> > (1) Measure power input (watts, not V.A.)
>
>
> Maybe a dumb question: How do *YOU* measure watts?
I have done it two ways: One using a power meter which takes phase
angle into account (measures heating), and by monitoring current
on the scope simultaneously with voltage and calculating using
the phase angle between them using the values measured. For non-
sinusoidal current waveforms which often arise in given the types of
transformers we use this can be a bit tricky. Shunted transformers
such as uWave oven transformers have a shocking (NPI) current
waveform. One can almost feel the pain of the circuit breakers,
fuses, wall connections etc when one of these little monsters is
hooked up.
Malcolm