Re: Watt meters

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Original poster: "Jim Lux" <jimlux-at-earthlink-dot-net> 


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From: "Tesla list" <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Wednesday, March 17, 2004 8:16 PM
Subject: Re: Watt meters


 > Original poster: "Gerry Reynolds" <gerryreynolds-at-earthlink-dot-net>
 >
 >
 > Hi Terry,
 >
 > So does this mean if I put a pure inductor across the mains (sized for say
 > 10 amps), the watt meter will register no power being consumed??  If this
is
 > true, how long has this been done this way?
 >
 > Cheers,
 > Gerry R

yes... and pretty much forever..

The original usage meters (in DC Edison days) were electrolytic cells with
silver electrodes.  The silver would plate from one to the other.
periodically, they'd weigh the two plates, then interchange them.  This
would be a coulomb sensor, and reactive power would transfer silver.

I suspect (without actually doing any hardcore research) that the present
electrodynamic meters have been around since 1900 or earlier, pretty much as
soon as AC distribution came into being.  The idea of power factor and
reactive power was known and understood very early on.

Actually, an interesting question, though.