Contrary to popular belief, induction motors consume very little electrical energy.
Instead, they convert electrical energy to mechanical torque (energy). Interestingly
enough, the only component more efficient than the motor, in a motor system, is the
transformer. The mechanical torque that is developed by the electric motor is transferred,
via coupling system, to the load.
The electrical energy that is consumed by electric motors is accounted for in losses.
There are two basic types of losses, Constant and Variable, both of which develop heat
Core Losses: A combination of eddy-current and hysteresis losses within the stator
core. Accounts for 15 to 25 percent of the overall losses.
Friction and Windage Losses: Mechanical losses which occur due to air movement and bearings. Accounts for 5 to 15 percent of the overall losses.
Stator Losses: The I2R (resistance) losses within the stator windings. Accounts for 25 to 40 percent of the overall losses.
Rotor Losses: The I2R losses within the rotor windings. Accounts for 15 to 25 percent of the overall losses.
Stray Load Losses: All other losses not accounted for, such as leakage. Accounts for 10 to 20 percent of the overall losses.