• The Indian Electric Co (Indian Electrical Industries)

Crane Duty Motors

Crane Duty Motors are used in many applications like: The driven equipment is to be accelerated rapidly with a fixed sequence of operation and uniform load conditions, Almost identical load conditions having both directions of rotation, Speed control not necessary, Robust and maintenance free requirement considering site conditions, Reduced cost considerations, Normally used upto 250M frame size. A sequence of identical duty cycles, each consisting of a period of operation at constant load and de-energized rest period, these periods being too short to attain thermal equilibrium during one duty cycle. In this duty type the break-away starting current does not significantly affect the temperature rise for this duty type. Unless otherwise specified, the duration of the duty cycle is 10 minutes, The recommended values for CDF are 25,40 and 60 percent. A sequence of identical duty cycles, each consisting of a period of starting, a period of operation at constant load and a de-energized rest period, the operating and rest period and de-energized periods being too short to attain thermal equilibrium during one duty cycle. In this duty, the stopping of motor is obtained either by natural deceleration after disconnection of the electric supply or by means of braking such as a mechanical brake which does not cause additional heating of the winding.