Since it is an old motor, better perform some basic experiments in your lab or workshop, rather than rely on any data sheets. What is the equivalent NEMA class of this motor ?

-Sanjay

Dear Mr. Roy,

Thank you for reply. I do not know about the NEMA class of this motor. It seems that I need to carry out an experiment or I need to extract necessary information from previous measurements.

I suggest to carry out the standard tests (open circuit test as a motor, open circuit test as a transformer if it is slip-ring motor, blocked rotor test and dc test) to determine its equivalent circuit parameters. then, use the torque/slip relation given in all machine text books to determine what you want. 

Hi,

I checked the Datasheet. You rather get the motor tested (as per IEC 60034 2 1) and check for efficiency and quality. The tests will give you data for establishing load torque and speed curves.

Hope this helps.

Regards,

Arun, 

 Altan,

The reason I asked for the equivalent NEMA class has something to do with the tests. If it is equivalent of NEMA class-A, then the tests are simple, and what Mohammed has suggested to take care of most stuff.

However, if it is equivalent of NEMA class B, C, or D, then the tests are more involved.

In any case since the motor is an old one, I wouldn't trust past data. A new set of experiments is always better.

With best wishes.

-Sanjay

Dear Altan Onat

refer the link

http://www.electrical4u.com/torque-equation-of-three-phase-induction-motor/

Dear Jenifer Amla,

Thank you for your answer. we have already determined it by carrying out the standard tests reported in the book Principles of Electric Machines and Power Electronics by P. C. Sen.

Besides, again thanks to all researchers who respond to this question.

With my kind regards.

Altan.