Electrical machines are not 100% efficient because some energy is lost in different forms. The major losses in electrical machines include:
- Copper Losses (I²R losses): These occur due to resistance in the winding conductors and depend on the square of the current.
- Iron Losses (Core Losses): These include:
- Hysteresis Loss: Caused by repeated magnetization and demagnetization of the core.
- Eddy Current Loss: Small circulating currents generated in the core, which produce heat.
- Mechanical Losses:
- Friction Loss: Occurs in bearings and moving parts.
- Windage Loss: Caused by air resistance when the rotor moves.
- Stray Load Losses: Minor losses due to distortions in current and voltage waveforms.
- Dielectric Losses: Occur in insulation materials due to alternating electric fields.
Reducing these losses improves the efficiency of the machine. For example, laminated cores reduce eddy current losses, and better cooling systems minimize heat-related losses.