These series of three phase metallurgical industrial and crane motors, with wound or squirrel cage rotor are specially designed to drive metallurgical industrial cranes and other similar machine, it has excellent overloading capability and high mechanical strength. Therefore, it is well suited for short duty cycle, or intermittent periodic duty, and on equipments with frequent starting and breaking or are subject to vibration and shock.
The standard range of power output and mounting dimensions complies with the recommended standard of IEC60072. The relation between range of power output and mounting dimensions are similar to the Japanese standard (JEM1202) and German standard(DIN42681),therefore most of them can be interchanged.
1, Short Time Duty(S2): Operation is under constant load in fixed time and the motor is resting or de-energizing when the heat balance is not reached. In a period of time, the motor is cooled and the temperature difference between motor and medium is limited within 2K.
2, Intermittent Periodic Duty(S3):To run according to series of identical cycles, the running time under constant load and time of rest de-energized are included in period of one cycle(see Fig.1), but the time is shorter and does not make motor to a heat balance condition. The starting current shouldn't be enough to affect the temperature rise obviously.
3, Intermittent Periodic Duty with Starting(S4): To run according to a series of identical cycles, each cycle is formed by a starting time, a constant load's time & a rest or de-energized time(see Fig.2), but the time is short without condition making the motor to a heat balance.
4, Intermittent Periodic Duty with Starting and Electric Braking(S5): It runs according to a series of identical cycles, there are starting time, constant load's time, electric quick braking time and a rest or de-energized time in each cycle, but the motor can't reach the condition of heat balance in such short time(Fig.3).