# Multi-winding / part winding motors CEC 28-800



## Vintage Sounds (Oct 23, 2009)

A six lead wye-delta motor is only designed to run on a single voltage and does not have multiple windings, it just has all of its leads brought to the J box. All of its ratings come from operation under delta connection. I don't think this puts it in the same category as a 9-lead dual voltage motor since those are always delta or always wye and able to meet nameplate ratings under both voltages. The OLs in a wye delta starter will see 57.7% of the running current and the starting torque will be 1/3 of across the line.


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## JRaef (Mar 23, 2009)

It's really about how you use it. 12 lead motors can be configured as dual voltage, Wye-Delta or Part Winding, it all depends on how you connect it to your starter externally of the motor.


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## Judoka (Oct 13, 2012)

Yea, this has got me wondering. I thought Wye delta starting ,was considered multi-winding. So if that's the case, then according to code, each winding must have its own overload device. However ,typically, on a wye delta, I usually see one overload for the motor circuit.


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## JRaef (Mar 23, 2009)

Judoka said:


> Yea, this has got me wondering. I thought Wye delta starting ,was considered multi-winding. So if that's the case, then according to code, each winding must have its own overload device. However ,typically, on a wye delta, I usually see one overload for the motor circuit.


No, on a Wye-Delta motor there is ONE set of windings doing the work, all you are doing is, in essence, connecting them in series (Delta) or parallel (Wye). They are still only and always all connected and protected by the same service. In a Part Winding motor or a 2 Speed 2 Winding motor, you can have only one set of winding connected at a time*, hence the requirement for separate SCPDs and OL protection.

*Technically on a PW motor, you are SUPPOSED to only use the Start winding for a short time when accelerating, but it is still connected separately from the Run winding even afterward.


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