induction motor performance
induction motor performance
(OP)
Three-phase induction motors are being supplied by an OPEN Y-DELTA transformer bank, i.e., there are only two primary phases.
If one of the primary phases opens, what is the effect on the motors ?
If one of the primary phases opens, what is the effect on the motors ?





RE: induction motor performance
Gunnar Englund
www.gke.org
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Half full - Half empty? I don't mind. It's what in it that counts.
RE: induction motor performance
RE: induction motor performance
Or do you mean a V connection?
Gunnar Englund
www.gke.org
--------------------------------------
Half full - Half empty? I don't mind. It's what in it that counts.
RE: induction motor performance
RE: induction motor performance
If you lose one phase the other phase will still provide full voltage and any running motors will be singled phased.
Bill
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"Why not the best?"
Jimmy Carter
RE: induction motor performance
Gunnar Englund
www.gke.org
--------------------------------------
Half full - Half empty? I don't mind. It's what in it that counts.
RE: induction motor performance
The first transformer on A phase is connected as a single phase distribution transformer which in North America has the secondary center tap/neutral grounded. This gives us A phase from L1 and L2. Two more transformers are connected to B phase. One of these transformers is connected to the neutral point to provide B phase. The third transformer is connected to L3 of the first transformer in such a direction as to produce C phase.
Typical transformer sizes may be 50 KVA, 25 KVA and 25 KVA.
Bill
--------------------
"Why not the best?"
Jimmy Carter
RE: induction motor performance
Have a look at a Scott connected transformer. I can't claim to have invented it, but sounds similar to what you describe.
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If we learn from our mistakes I'm getting a great education!
RE: induction motor performance
B
/
/
A _____/_____ D
N /
/
/
C
A-D is one transformer. (It may be two transformers if there is enough space on the pole to mount four transformers.)
N-B is the second transformer.
D-C is the third transformer.
Voltage drops on the primary neutral may contribute to voltage unbalances.
An open delta (or "V" connection on your side of the pond) is used to develop C phase.
I first learned of this connection on Eng-Tips. I think that I remember that a poster was having some voltage balance issues that were probably related to voltage drop in the primary neutral conductor.
Bill
--------------------
"Why not the best?"
Jimmy Carter