Torque Calculation

S

Thread Starter

sanjay patil

Hi Friends,
Can anybody help me in calculating of required starting & running torque value from moment inertia (WR2 or WK2)& RPM of load.

Thanks
Sanjay Patil
 
Responding to Sanjay Patil's Thu Jul 8, 1.22:pm query... I suggest the following approach:

1) Use NEMA Standard MG 1-20.42. It contains a table derived from an empirical formula that relates load WR2 and motor Hp & speed.

2) Knowing Hp and speed calculate the required torque.

3) Use NEMA Design Letters, example B, C, D, to determine breakaway torque, accelerating torque (you must know the load torque), pullup
torque, and slip.

4) Calculate acceleration-time for the selected NEMA Design Letter.

5) Calculate rotor losses to insure that the motor's temperature-rise over a given ambient is not excessive.

Caution... certain assumtions are made regarding the load's torque vs speed characteristics and duty. They are defined in the Std.

Regards,
Phil Corso, PE {Boca Raton, FL, USA}
[[email protected]] ([email protected])
 
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