Re: Input power measurement

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

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