S2 service asyncronous motor

[uhpo]

i got a italian S2 service asyncronous motor, 90 kw and normally i saw S2 50 % or something like this, but this time it´s only S2 no time or percentage.... so how much time it could works.

thanks

 

[ScottyUK]

Depends on the duty - a long acceleration time will put a lot of heat into the rotor compared to a load which accelerates quickly. Thats why the IEC definition says:

"The motor works at a constant load, but not long enough to reach temperature equilibrium. The rest periods are long enough for the motor to reach ambient temperature."


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If we learn from our mistakes I'm getting a great education!

 

[uhpo]

so it´s not the manufacturer who define the time the motor is running? what´s the limit temperature? i must think that for class F isolation i could allow motor reach 155ºC before i would stop it?

thanks

 

[ScottyUK]

These motors are normally designed for a specific purpose, so the manufacturer will design for that specific duty. You can almost guarantee that wherever you put your thermocouple will not be where the hotspot is, so leave a bit if margin between whatever you measure and the insulation limit.


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If we learn from our mistakes I'm getting a great education!