90 degree phase rotation commercial power

[Jay Jaeger]

On 8/26/2015 3:48 PM, Christian Kennedy wrote:
> 
> On 8/26/15 12:33, Paul Koning wrote:
> 
>> 90?  Three phase power is 120 degrees apart, center-tapped "two
>> phase" home power is 180 degrees, but I don't know of any power
>> company service that produces 90 degree shifts.
> 
> There's a bunch of 90-degree two-phase stuff in Philadelphia; in
> particular the city center has a lot of buildings that are fed 90-degree
> two-phase from PECO.  I suspect (but do not actually know) that PECO
> derives two-phase from three-phase using Scott-T transformers.
> 
> 

Man, sometimes one can be right by accident!  (I did really mean to say
120 degrees, originally).

JRJ