In this topic, you study Losses in Induction Motor.
Different types of losses which occur in an induction motor are as follows
- Copper losses
- Iron losses or Core losses
- Mechanical losses
Copper Losses
These are the I2R losses which occur due to current flow through the resistance of the stator and rotor windings of the motor. These losses depend on the load on the motor. Use of the material with good conductivity, like copper, for the windings of the motor helps in reducing these losses.
Iron Losses or Core Losses
These losses (consisting of hysteresis and eddy current losses) occur in the stator and rotor cores. The stator core loss depends on supply frequency and flux density in the stator core. Since the rotor frequency under normal operating condition is very small, the rotor core loss is negligibly small. As already mentioned previously, in view to reduce the core losses, both stator and rotor cores are built up using high grade silicon steel laminations. Under constant voltage conditions, core losses together are always assumed to be constant at all loads and speeds.
Mechanical Losses
These losses include friction and windage losses. Since the speed of the induction motor varies slightly over the working range, these losses are assumed to be constant regardless of the load. It should be noted that the core and mechanical losses together are sometimes referred to as constant losses or rotational losses.