Checking rotation on a 4160/120 control power transformer

[bean9677]

I was told I could check the rotation of the incoming power to my motor starter , on the 4160/120 volt control power transformer. As long as the transforer has a center tap. Is this correct and how does it work?

 

[templdl]

I was told I could check the rotation of the incoming power to my motor starter , on the 4160/120 volt control power transformer. As long as the transforer has a center tap. Is this correct and how does it work?

Rotation on a 4160/120v cpt? I though it is 1ph. What does "center tap" have to do with it?

 

[Jraef]

If it is a CPT, then they are usually single phase, which means no can do, you have no relative phase shift with only 2 of the 3 phases as tempdl said.

If however someone is looking at a VT used for metering for example, then it might be 3 phase and checking rotation there would be valid... Sort of.

Checking rotation of the SUPPLY is only relative for some tasks, but is NOT a guarantee of motor rotation, unless the motor has already been tested and the leads marked to intricate the correct phasing of the line connection.