What seems to be the difference?
- Thread starter darekelec
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- San Francisco Bay Area, CA, USA
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- Electrical Engineer
Almost none from a practical use standpoint. In the case of 2-out-of-3 phases, the voltage reference would ONLY apply to a Line-to-Line voltage. When using the broader definition of "single phase", the term could also be inclusive of Line to Neutral voltage levels. But if you are looking at 240V from a single phase transformer, or 240V from 2-out-of-3 phases on a 240V Delta 3 phase transformer, the details are lost on the load, it will not make a difference.
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- Placerville, CA, USA
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- Retired PV System Designer
But capacitive leakage and voltage from terminals to ground will be different, and that can affect the behavior of an appliance that contains the line to line load.
gar
Senior Member
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- Ann Arbor, Michigan
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- EE
140710-2211 EDT
darekelec:
There may be a big difference depending upon what is the reason and basis for your question.
For example:
If you connect a TED 1000 energy monitor to a split-single phase source the power and energy measurements will be approximately correct. Connect to two phases of a 3-phase system and there can be a substantial error.
Connect a 10 ohm resistor line-to-line to the two different sources and the power dissipated will be different. Less on the 3-phase system because line-to-line is 208 and not 240.
On the center tapped single phase system the two voltages relative to the center tap are 180 deg out of phase. On the 3-phase Y system the phase shift of one line to Y-center is 120 deg out of phase with either of the other two lines to Y-center.
.
darekelec:
There may be a big difference depending upon what is the reason and basis for your question.
For example:
If you connect a TED 1000 energy monitor to a split-single phase source the power and energy measurements will be approximately correct. Connect to two phases of a 3-phase system and there can be a substantial error.
Connect a 10 ohm resistor line-to-line to the two different sources and the power dissipated will be different. Less on the 3-phase system because line-to-line is 208 and not 240.
On the center tapped single phase system the two voltages relative to the center tap are 180 deg out of phase. On the 3-phase Y system the phase shift of one line to Y-center is 120 deg out of phase with either of the other two lines to Y-center.
.
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