RE: Single vs Two Phase (was - Spark gap erosion resistance)

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

Original poster: "John H. Couture by way of Terry Fritz <twftesla-at-qwest-dot-net>" <couturejh-at-mgte-dot-com>


Richard -

Ed is correct and the system is single phase not two phase. To understand
electrical phasing you have to use vectors. The two phase 220 volt you are
referring to would be zero volts not 220 volts. Note that the oposite vector
"trough?" at 180 degrees is also at the oposite polarity and would be
subtracting not adding to the voltage. Note also that the three vectors
"hots?" are at 208 volts not 220 volts if the Y vectors are 120 volts and
arranged correctly. You can check this out and a lot more by reading any
electrical engineering book on AC circuits.

In the past 15 years this subject has been discussed several times on the
List and it appears coilers are still having trouble understanding the
voltages and vectors involved with AC circuits.

John Couture

-----------------------------------------

-----Original Message-----
From: Tesla list [mailto:tesla-at-pupman-dot-com]
Sent: Saturday, January 05, 2002 10:12 PM
To: tesla-at-pupman-dot-com
Subject: Re: Single vs Two Phase (was - Spark gap erosion resistance)


Original poster: "Wall Richard Wayne by way of Terry Fritz
<twftesla-at-qwest-dot-net>" <rwall-at-ix-dot-netcom-dot-com>

Ed,

Sorry about the phase illusions you seem to be operating under. 8>)  120 vac
is
single phase varying around the neutral.  220 two phase vac has two hot
wires,
each varying around neutral and their phases are 180 electrical degrees
apart.
As one peaks the other is at the opposite trough 180 electrical degrees away
at
the same instant.  Of course, 220 three phase vac has three hots all 120
electrical degrees apart.

If you're interested any electrical utility would be happy to explain it to
you.  As an aside, I have had all three three types at one time or another.

RWW
>
> > John.
> >
> > Sorry, but standard 220 vac comes in both two and three phases from the
> > electrical utilities.  The two phase system is 180 degrees apart and
three
> > phase of course is 120 degrees apart in phase.
> >
> > RWW
>
> WRONG AGAIN.  The normal resedential installation is a three-wire,
> SINGLE-PHASE system.  (In effect, a center-tapped single-phase system.)
> A true two-phase system has voltages which are 90 degrees apart. This
> definition has used since at least Tesla's time, and probably earlier.
>
> Ed