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Re: Input power measurement



Original poster: "Skip Greiner by way of Terry Fritz <teslalist-at-qwest-dot-net>" <sgreiner-at-wwnet-dot-com>

Hi DWP
I have a couple of standard house style watt-hour meters that I purchased
just for this application. The problem is that the dials rotate too slowly
to be useful. Does anyone have any ideas as to how to soup up the dials.
Skip

-----Original Message-----
From: Tesla list <tesla-at-pupman-dot-com>
To: tesla-at-pupman-dot-com <tesla-at-pupman-dot-com>
Date: Tuesday, March 11, 2003 6:56 AM
Subject: Re: Input power measurement


 >Original poster: "davep by way of Terry Fritz <teslalist-at-qwest-dot-net>"
<davep-at-quik-dot-com>
 >
 >
 >>Now the question becomes...how does one measure the
 >
 >>actual (RMS ?) input current
 >
 >         Irrelevant (nearly) to wall plug watts.
 >         (AC is more complicated than DC...)
 >
 >>in order to calculate the wall plug watts?
 >
 >         Need to measure:
 >                 RMS Volts (coil load mat be distorting or
 >                 loading the nominal value.)
 >                 RMS AMPS (same same)
 >         AND
 >                 Phase Angle between them...
 >         Even if RMS Volts and Amps are known the phase
 >         angle is needed.
 >         Or:
 >
 >>Must one purchase or borrow a multi-buck wattmeter?
 >         I think i paid under $20 for any of mine.
 >
 >         But i Shopped Around at fleas and did not
 >         Have one Instantly.
 >
 >         Another Approach, which i have not done in detail,
 >         is workable:
 >                 Figure out how to interpret the electric
 >                 meter on the building.  THAT READS in
 >                 WATTHOURS and these can be calculated back
 >                 to WATTS.
 >
 >
 >         It has a guaranteed accuracy.
 >         It DOES the phase calculation/correction.
 >         It Assumes reasonable wave shape, but is likely
 >         close.
 >
 >
 >         May require an assistant to read, and will require
 >
 >         some maths.
 >
 >
 >         (I'll sketch in a procedure if there is interest...)
 >
 >         ALSO, such meters ARE SOLD, used.  Might get one
 >         from similar places as pole pig & other power co
 >         hardware.  An extra, mounted Just for the Coiling
 >         would be easier to read...
 >
 >--
 >         best
 >         dwp
 >
 >...the net of a million lies...
 >         Vernor Vinge
 >There are Many Web Sites which Say Many Things.
 >         -me
 >
 >
 >
 >
 >