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Re: Input Power Measurement
Subject: Re: Input Power Measurement
Date: Fri, 30 May 1997 10:58:31 -0700
From: Skip Greiner <sgreiner-at-wwnet-dot-com>
Organization: Greiner, Ltd.
To: Tesla List <tesla-at-pupman-dot-com>
References: 1
Tesla List wrote:
>
> Subject: Re: Input Power Measurement
> Date: Wed, 28 May 1997 10:51:30 -0500
> From: "Robert W. Stephens" <rwstephens-at-headwaters-dot-com>
> To: Tesla List <tesla-at-pupman-dot-com>
>
> > Date: Tue, 27 May 1997 00:46:40 -0500
> > To: tesla-at-poodle.pupman-dot-com
> > Subject: Input Power Measurement
> > From: Tesla List <tesla-at-pupman-dot-com>
>
> > Subject: Input Power Measurement
> > Date: Mon, 26 May 1997 23:42:39 -0700
> > From: Skip Greiner <sgreiner-at-wwnet-dot-com>
> > Organization: Greiner, Ltd.
> > To: tesla list <tesla-at-pupman-dot-com>
> >
> >
> > Hi All
> >
> > It is obvious to all that any given transformer can be run in excess of
> > its rating. Thus, a 1kva transformer may be run with 2kva input and
> > live. This does not mean that the TC is being run at 1kva since the
> > transformer is rated at 1kva.
> >
> > How can the actual input power to the TC be measured????????
> >
> > We can know the input voltage, I think, since most of us run from the
> > mains (except those that insert a variac and transform the mains voltage
> > up to 130v or 140v). We can still measure the output voltage of the
> > variac, I think, and therefore know the input voltage.
> >
> > BUT....how can the input current be measured. I seriously doubt that it
> > is sinusoidal. There are ac ammeters, several different types which give
> > an indication. Is there one type of ammeter, the reading of which could
> > be multiplied by the voltage as obtained above, which would give an
> > input power which all of us could use for comparison purposes?
> >
> > I have a commercial instantaneous reading wattmeter. Does it provide any
> > usable information? For instance....if I compare the input power to two
> > different systems which use different types of input
> > transformers....will I indeed be able to say that one system is more
> > efficient than the other?
> >
> > Any suggestions would be appreciated.
> >
> > Skip
> >
>
> Skip,
>
> I think you could install a voltage probe and wideband current
> transformer on
> the mains input to your variac, connect it to a CRAY with a powerful
> program that someone on this list would no doubt love to write, and
> get a three dimensional color printout of your true RMS and peak
> power.
>
> I would think you could also go the route of the good old hotwire
> ammeter
> (good way to measure RF power coming out of a transmitter) in series
> with your variac input and settle for knowing average RMS power with
> a fair degree of accuracy. Any fellow deciples of the KISS Principle
> try this yet?
>
> rwstephens
Hi All
I can get access to the Cray. Does anyone have a program?
Skip