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WYE Motor Connections

WYE Motor Connections

WYE Motor Connections

(OP)
What will happen if on a WYE connected motor TI, T2, and T6 are connected to the power circuit and T4, T5, and T1 are connected together?

RE: WYE Motor Connections

depends on how long it was energized attempting to start it.  Are you trying to indicate that one phase was reversed or was there more wrong with the connection?

RE: WYE Motor Connections

(OP)
Sorry, I typed the connections incorrectly.  The motor was connected T1, T2, T6 to the power supply and T4, T5, T3 were connected together.

RE: WYE Motor Connections

Hello KMAYEUX,
Your gonna have a shift phase, the motor will run WITH HIGH AMPERAGE AND WILL SOUND STRANGE LIKE is like a two phase operation.

Regards

Petronila    

RE: WYE Motor Connections

I assume what you meant was
"TI, T2, and T6 are connected to the power circuit and T4, T5, and T3 are connected together" ?

Also I assume T1, T2, T6 connected in same rotation sequence as would normally connect T1 T2 T3.

One thing for sure is that you definitely cannot predict any reliable operating mode of the motor. It may overheat and may have abnormal current or vibration or other problems.

With that said, trying to analyse the connection I get an unusual result. You will have converted FROM
a b' c a' b c'  etc
TO
a b c a' b' c' etc

The fundamental component of the resulting magnetic field rotates at one-half the original speed.  So it seems possible in theory you could have stable operation at one-half motor speed (carrying some load).  Surely the harmonic design of the motor would be destroyed and therefore if such stable operation were possible you might likely have some problems with vibration and anomalies such as cogging and cusps in torque speed curve.

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RE: WYE Motor Connections

a b' c a' b c'  follows in the sequence listed for a c b sequence applied voltage

while
a b c a' b' c' follows in the sequence listed for a b c sequence applied voltage.

So that theoretical 1/2 speed mode I mentioned would also be reversed in direction.

Also if it was successful there would be substantially reduced fundamental primary flux due to lack of constructive addition of adjacent poles. Result is that if the motor could run at half speed, the torque capability would be reduced and horsepower (torque times speed) reduced by factor of more than 2.

I'm a little bit out on a limb on all this. I've certainly never tried it. Interested to hear any other comment on whether a motor could be made to operate in reverse at half speed through intentional miswiring.

=====================================
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RE: WYE Motor Connections


It seems that you switched the terminals of one phase (T3-T6). Am I right?

Tommy

RE: WYE Motor Connections

(OP)
Tommy007

You are correct.  The leads from one phase were reversed.

Ken

RE: WYE Motor Connections


Did you try this and know the answer (and just testing us) or not?

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