Re: AVERAGE Power

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

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

Hi Gary,

I think "i" started this one :-O  

Of course, you are correct.  I meant "average power" not the fairly
meaningless term "RMS power".  Sorry bout that!

I should mention that finding average power by multiplying the RMS voltage
by the RMS current by the power factor only works for steady state sine
waves.  Tesla coils are far to messy for that.  This is where the piecewise
integration of instantaneous voltage and current that MicroSim can do is so
useful.  It can take very messy voltage and current waveforms and find the
average power.  In the real world, I have to save the waveforms off the
digital scope into numeric files and let other software crunch that data to
find the average power.  There are some nice power meters that could do it
too but they are pricey in the bandwidths we need for Tesla coils.

Cheers,

	Terry

At 01:57 PM 1/7/2001 -0600, you wrote:
>Sorry to pick nits, but a recent reference to RMS power set me off, rather
>like fingernails on a slate blackboard.  Our meters measure measure average
>voltage and current on the dc ranges, rms voltage and current on the ac
>ranges, but only AVERAGE power (never RMS power). Average power is the
>product of rms voltage, rms current, and power factor. It is possible to
>mathematically define a quantity called rms power, but it has no physical
>meaning that I know about.
>
>Gary Johnson
>