A continuing challenge for electric motor manufacturers and motor users is delivering more shaft power while using less input power, which simply put means increasing the motor's efficiency. Motor efficiency improvements extend the life of battery-powered products, save on energy costs and reduce the amount of heat that can cause damage and increase in-field service and warranty costs. Higher power efficiency also means lower internal power losses.
- Copper winding (function of conductivity of copper and the resistance of the stator coils)
- Coulomb friction (brushes, bearings and shaft seals, etc.)
- Viscous friction (bearing lubrication, certain materials damping characteristic as a function of speed)
- Hysteresis (magnetic memory in motor's soft iron members)
- Eddy currents (primarily soft iron losses caused by material type and thickness of laminations, material induction levels, commutation frequencies. Losses vary as a function of speed squared)
- Windage (aerodynamic effects due to motor geometry and speed)
- In most applications, the copper winding losses are the largest contributor to an inefficient motor. These losses are computed by multiplying the input current squared by the winding resistance of the stator. The conductivity and resistance of copper are among the lowest per foot of any current carrying material. Only at higher speeds do eddy current losses become significant.
I think I found my answer. I think.