Single Phase Power

[tpc]

Is there a phase difference in the signals on two wires connected to one leg of a delta configuration 115 Vac 60 Hz power source? What should be measured across the two wires? What should be measured from each wire to ground? [sig][/sig]

 

[jbartos]

Please, would you rephrase the posting in therms of two signals on two wires. This would normally imply a multiplexing or some other processing of two signals. [sig][/sig]

 

[peterb]

Depends on what you are measuring - & against what reference.
Define your delta triangle as ABC, with the phase you are concerned about being AB. If you use BC as the reference, then AB will show an angle of 120 degrees lead, BA will show 60 degrees lag. With CA as the reference, then AB will show an angle of 120 degrees lag, BA will show 60 degrees lead.

As far as readings to ground are concerned, that depends on whether the delta is grounded or not. If it isn't grounded, then the (balanced) system capacitance will establish a neutral point roughly at the centre of the triangle. Again using BC as the reference, A-g will show a lead angle of around 90 degrees, while B-g will show a lag angle of around 30 degrees.
With say the C corner of the delta grounded, A-g will show 60 degrees leading, with B-g showing 0 degrees against BC reference.
If the midpoint of say BC is grounded, then A-g reads 90 degrees lead and B-g reads 0 degrees against BC reference.

The key is that you need to establish a proper reference to measure against [sig][/sig]