Unbalanced load in 3 phases system
Unbalanced load in 3 phases system
(OP)
Dear All,
Could someone please inform me about what happens to the unbalanced current that returns in the neutral conductor in a three phases transformer??does it get dumped in the grounding loop connected at the star point of the transformer or it stays trapped inside the circuit?
Thank you all in advance :)
Could someone please inform me about what happens to the unbalanced current that returns in the neutral conductor in a three phases transformer??does it get dumped in the grounding loop connected at the star point of the transformer or it stays trapped inside the circuit?
Thank you all in advance :)






RE: Unbalanced load in 3 phases system
A three phase transformer bank with the secondary connected in star.
The A phase winding is supplying 100 amps to the load.
The B phase winding is supplying 100 amps to the load.
The C phase winding is supplying 150 amps to the load.
There Amps of unbalance on the neutral. This will return to the C phase winding.
100 Amps from each phase will cancel.
Bill
--------------------
"Why not the best?"
Jimmy Carter
RE: Unbalanced load in 3 phases system
It sounds like you are caught up in that old example the flow of
electrical current is like water flowing through a hose. Nothing
could be further from the truth. If you take a simple circuit like
a lamp and connect the two wires from the lamp to 120 volts the lamp
lights. At the time the voltage is applied the electrons in the conductor
begin vibrate and bounce around in both conductors. There is actually little
movement in the wire. The electrons that move are considered drifting. This
drift can be calculated but not here. The actual movement is about one millimeter
per second depending on the actual amperage and conductor size. The flow of the
current moves back to the source so that everything is like it was before
the voltage was applied. The electrons do not just disappear. I have a site
that does a good job with your question. I hope this helps.
http://amasci.com/miscon/whatis.html
RE: Unbalanced load in 3 phases system
So there is a limit that unbalance should be within 3%
RE: Unbalanced load in 3 phases system
So the answer to your question is that current (both physically and mathematically) cannot be trapped. It must complete its loop back to the source, one way or another.
Best to you,
Goober Dave
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RE: Unbalanced load in 3 phases system
That would be a code violation in North America. If loads are connected from line to neutral, a neutral conductor back to the source must be provided.
Exception: There are some areas where rural distribution systems use a ground return in place of a neutral conductor.
Bill
--------------------
"Why not the best?"
Jimmy Carter
RE: Unbalanced load in 3 phases system
Best to you,
Goober Dave
Haven't see the forum policies? Do so now: Forum Policies