To: mail11:;-at-msd26.ENET.dec-dot-com (-at-teslatech)
From: "I am the NRA." <pierson-at-msd26.ENET.dec-dot-com>
Date: Wed, 1 Nov 95 17:24:00 EST
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(hmmm. I missed this the first time by.)
>>> In addition,
>>> since 240V is really two 120V lines with a 90 degree phase difference,
Not now. Tesla (ahemmmmmm) had a two phase system like this. 8)>>
>Just to split hairs, the phase difference is 180 degrees between the
>two phases (for "single" phase power)
ummmmmmm. Delicate point. Depends on how the measurement is made.
If it is measured from the poitn of view of a scope referenced to
the usual neutral, yeah 180.
"measured" as a 240v load sees it, hot to hot, the phasing is 0.
_zero_. If it was 180, then the voltage across the outside would
be _zero_. Its not. Its 240.
(I once got into a nearlyoutandoutflamewar on this some years back.
We FINALLY figgered out that the "180_folk" wqere measuring from the
neutral/gnd. I was "measuring" cross the load. Float the scope.
measure from one hot to neutral (careful, unless skilled), then probe
a second probe from first hot to second hot. All in phase.)
(And Chip implicitly covered the "other" "240" v system. Explicitly: Some
systems give a "240v" feed by tapping across two phases of a three phase star.
This leaves 208 nominal, and 120(60) phasing....)
(who will be off the net until Monday....)