Today, in almost every application, electric motors are used, and electrical drives are used to control them. But not all motors have the same working time. Some motors run all the time, and some motors have a shorter runtime than the rest period. Depending on this, the concept of motor duty class is introduced and based on this the duty cycles of motor can be classified into eight categories viz.
- Continuous duty.
- Short time duty.
- Intermittent duty.
- Intermittent duty with starting and braking.
- Continuous duty with intermittent loading.
- Continuous duty with starting and braking.
- Continuous duty with frequent speed changes.
That’s what this obligation shows, the engine is running sufficiently long and the temperature of the electric engine arrives at a consistent state. These engines are utilized in paper plant drives, blowers, transports and so on.
Short Time Duty:
In these engines, the operating hours are exceptionally short and the warm-up time is much shorter than the cool-down time. In this way, the engine warms up to temperature before operating again. These engines are used in crane drives, drives for household appliances, valve drives, etc.
Intermittent Periodic Duty:
Here the motor runs for some time and then there is a rest interval. In both cases, there is insufficient time to raise the temperature to steady state or to cool to ambient temperature. This is seen on press and drilling machine drives.