frank cinker
Member
- Location
- Pennsylvania
Under normal conditions, on a 230 volt, ungrounded delta, what should the voltages be to ground?
3Ph ungrounded delta system 230 volts
- Thread starter frank cinker
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petersonra
Senior Member
- Location
- Northern illinois
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- Semi-retired engineer
just about anything is possible, or so i have been told.
normally it will be close to the same from each phase, about 130 Volts.
but I have seen it 20 or 30 volts different from one phase to another.
normally it will be close to the same from each phase, about 130 Volts.
but I have seen it 20 or 30 volts different from one phase to another.
- Location
- New Jersey
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- Journeyman Electrician
If the system is ungrounded shouldn't the voltage to ground be zero?
- Location
- Wisconsin
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- PE (Retired) - Power Systems
petersonra said:
Anywhere from 0V (which is most unlikely) upto 460V (and higher during a fault condition). It is all dependent on the system loading, coupling capacitance, and the input impedance of your meter. In reality, I would be most surprised to find a reading of 138V.
No way!
No way!
If the line to ground voltages were all zero, the line to line voltages would be zero as well. Not good.
Imagine equal stray capacitances between each line and ground. This would form a wye network, and Vline-ground would be Vline-line/1.732.
Of course this network would be easily unbalanced. Then we have a different problem.
No way!
infinity said:
If the line to ground voltages were all zero, the line to line voltages would be zero as well. Not good.
Imagine equal stray capacitances between each line and ground. This would form a wye network, and Vline-ground would be Vline-line/1.732.
Of course this network would be easily unbalanced. Then we have a different problem.
brian john
Senior Member
- Location
- Kilmarnock, Va
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- Retired after 52 years in the trade.
I ran into an ungrounded system with imbalance currents (single phase 208 loads), the voltage to ground varied with the phase loads. I did not mess with this as much as I might today (this was 26 years ago). I just grounded the XO like it should have been.
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- New Jersey
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- Journeyman Electrician
jim dungar said:
How would you get 460 volts from a 230 volt system?
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- Wisconsin
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- PE (Retired) - Power Systems
infinity said:
During a fault condition it is possible to approach 2x line-line voltage on ungrounded delta systems. It is not common and has to do with when and where the fault occurs.
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