RTD placement in stators

[gronk2003]

If a motor has 6 RTD's, is there any standard, other than 2 per phase, that says how they are to be distributed? EG Phase 1 having RTD's 1 and 4, Phase 2 RTD's 5 and 2 and Phase 3 RTD's 6 and 3?

Also, how much of a temperature difference would you see in a stator assuming you had a problem in one phase?

 

[aolalde]

There is not such a standard, unless it is the standard procedure for a particular company or organization.
Normally you put 2 RTD’s per each phase, located at the expected hot spots. The RTD’s are embedded in the slots and at the center of the core stack. Heat will move upwards so you expect the upper area will have more temperature. The maximum difference on a good stator is 10 °C between different locations.

 

[electricpete]

NEMA MG-1 says the minimum number of RTD's (when supplied) is one per phase. (atlhgough 6 is the norm).
It gives some requirements for detector length, width, positioning, but nothing about numbering.

I vaguely recall in the past in MG1 I had seen mention that temperature at different positions in the core should agree within 3C. I can't find it when I went back and looked today.


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