Rated torque is the torque provided by the motor on its live axle and rated currents. The maximum torque demands higher currents at the nominal current and therefore can not be supplied consecutively by the motor, it is intended to supply any load peaks. In this way, every induction motor has the capacity to provide a torque above the nominal for short periods of time. According to the standard, the engine must be capable of 60% over the rated torque for 15 seconds.
It should be noted that the Brazilian standard establishes categories of electric motors N, H, D, NY and HY. Each category institutes a particular form of torque curve X velocity. The choice of engine category is achieved by the type of load being driven. The catalog values in general refer to normal category motors, designated as N. With respect to starting torque, it is important to check that it must be higher than the starting torque of the load, so that the engine can accelerate and reach rated speed. Equally important is the maximum torque, which determines what overload the motor can withstand for a limited time. mrosupply