NEMA MG-1 Sealed Winding

[alkaz]

Dears,

Please i found on NEMA MG-1 / API541 standard that the Sealed Winding is need in order to be approved on conformance test which include a submergible or spray test. In my point of view, this is done to proof that the partial discharge will not occur on winding insulation due to a complete impregnated insulation (no gaps).

My question is, is this applicable for Low Voltage motors (<1kV)? My opinion is that, it is not applicable or not usefull because for Low Voltages the partial discharge is not so powerfull to cause any damages to insulation. Am right with my conclusion? Please comments.

Thanks,

 

[electricpete]

According to NEMA MG1, sealed winding conformance test is applicable both to integral/medium machines and large machines.

We specify that test only do it for large outdoor critical machines only.

I don't find small machines have as much problems with moisture causing winding failures as big outdoor machines. Also the small machines tend not to be as critical and the test will cost you.

=====================================
(2B)+(2B)' ?

 

[electricpete]

I should clarify my terminology is small/medium machines are 460vac. Large are 4kv and above. Roughly the same as NEMA although NEMA draws the distinction based on horsepower.

=====================================
(2B)+(2B)' ?