Most of the differences on induction motors due to 50Hz vs 60Hz come down to pull up torque, how the start windings are controlled and what rpm the start windings are turned off. We use custom motors that are duel Hz. rated. The normal problem with doing this is that if the motor is configured to drop out the start winding at the right rpm (using a centrifugal switch) for 50Hz, it is too early for 60Hz designs. The need for less efficient rotor laminations that the increase the inherent properties of pull up torque on the motor aid in configuring a motor that needs less of a starting circuit to get going under load. Solid state switches for starting circuits solve the rpm problem as long as there is sufficient input voltage to the motor during a full load start. On 115 volt circuits it is common for voltage drop due to the starting current of the motor to be a problem. When this happens the ratio of voltages between the starting circuit and the run circuits is distorted and the solid state switch can be fooled into keeping the starting circuit in too long or not long enough. If you have an application that does not need to start under load you will have a much easier time getting a motor configured that will operate on dual voltage and dual Hz. If your application is a tough one like a compressor or a pump then you are going to be faced with finding someone who can still make a motor with a pre-NEMA E-Pact/IEE841 requirements. These standards required motor manufacturers to increase the efficiency of their motors under load. Under dedicated Hz applications this does not cause much of a problem, but the more efficent laminations increase the motors dependence on the starting circuit. As the KW approaches 1.2 or higher on 115 volt circuits, the adverse effects of voltage drop become greater and greater. The best luck we have had is with Leeson and Marathon motors. (Both are owned by the same parent company and share manufacturing processes and facilities.) Good luck!
In India, supply system is 50 Hz, therefore the electrical equipment is designed to operate at 50 Hz. In USA, 60 Hz supply system is used.
The performance of the electrical equipment is adversely affected if operated above or below the rated design supply parameters. If 60 Hz, machine is operated at 50 Hz the torque delivering capacity of the motor gets lowered and motor has to be de-rated.
50 Hz & 60 Hz
Re: 50 Hz & 60 Hz
