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Re: IS 240VAC two-phase - NO



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

 > >If I connect a common low voltage transformer to 120vac I get 12.6 volts
 > >out. This is usually center-tapped. So I get two 6.3 volt supplies with a
 > >common, the tap. That doesn't mean I get 2 phase 12.6 volts. :)

 > > > when testing the house wiring with my O-scope ..  the 120V shows a
 > > > single
 > > > sine wave ...   when testing the 240 system it shows 2 sine waves
  had
 > > > to
 > > > use both leads)
 > > >
 > > > so how does a single phase get "split" via a center tap transformer to
 > > > produce the opposed phases ???
 > > >
 > > > Scot D
 >
 > Ok  Im back       did the center tapped test...    it creates the same
sine
 > wave set as the 240 volt system does...  kewlll...
 >
 > but my question still remains..  how does it create the 2 different sine
 > waveforms??
 >

Polarity inversion.  Think of the center tapped transformer as two separate
windings hooked in series:

+      <probe 1
winding 1
-
|    <scope ground
+
winding 2
-     <probe 2