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>


>I am using a 9kv at 120ma NST. In operation I use an

>iron vane ammeter (known to be within 5% accuracy) to

>monitor current. My mains voltage is nominally 117V.

>Interestingly the current into the NST is about 17A when
>running in resonant mode. It is my understanding that

>an iron vane meter reads true

         RMS?
         Roughly, yes...

>input current regardless of waveform.

         Within its limits of frequency response.

>Therefore my input power to the NST is nearly 2000 watts.

         _power_ is indeterminate with this arrangement.
         Input 'VA" (Voltamaps) us roughly 2000.
         input _power_ will be less.


>I would appreciate comments from anyone who can help explain

>the discrepancy between the 1080va rating of the "current

>limited NST

         It's _current_ limited, rather than power limited.

>and the measured input

         The measurement made is of VA rather than _power_.

         best
         dwp

...the net of a million lies...
         Vernor Vinge
There are Many Web Sites which Say Many Things.
         -me