IEC 60034-12 - starting torque?

[Tmoose]

We got a quote for some induction motors, taking exception to a starting torque of 2.8 x running torque.
That is not part of our spec, but we do reference IEC 60034.
We have No copies in house!
I see IEC 60034-12 is supposed to include starting characteristics of induction motors less than 660V.

Could I impose on someone to confirm whether starting torque that high is part of 60034-12 ?

thanks

Dan T

 

[ScottyUK]

Minimum torque to be developed is dependent on frame size, even though it's quoted in p.u. There are also three columns: locked rotor torque, pull-up torque, and breakdown torque. I assume you're looking for locked rotor torque? The standard lists Design N and Design H motors, being normal and high torque types respectively, and with sub-types NY and HY for Y-D starting.

Even with a Design H motor you'll only get more than 2.8 p.u. locked rotor torque if the motor is a small one; all the Design N and the larger Design H motors are lower than 2.8 p.u.

There isn't an upper limit on torque to be developed listed in the standard as far as I can see.



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

 

[7anoter4]

I agree with Scotty .The minimum 2.8 Ti it is close to NEMA design D.IEC design H is almost identical to NEMA design C.It is no such requiring in IEC 60034 as I see.