Motor Parts:
Stator: The stationary part with windings.
Rotor: The rotating part attached to the shaft.
Two-Pole Motor Example:
Stator: Energized, causing the rotor to make a half turn per current cycle due to attraction and repulsion.
Electrical Cycle: In the US, each half-cycle is 1/120th of a second, with a 60 Hz power supply.
Magnetic Attraction and Repulsion:
Like poles repel, opposite poles attract, leading to rotor movement.
Alternating current changes direction, maintaining motor rotation.
Motor Starting:
Motors need a phase shift to start rotation.
Phase Shift: Formed by various methods like shaded poles, out-of-phase start windings, capacitors, or three phases.
Shaded Pole Motors:
Characteristics: Low starting torque, low efficiency (30% efficiency), low cost.
Heat Problem: Inefficient motors waste energy as heat, increasing costs.
Phase Shift: Provided by copper bands on each pole.
Wiring: Simple connection with line, neutral, and ground wires.
Reversing Rotation:
Change the stator’s position and the fan blade’s orientation to reverse rotation.
Multi-Speed Shaded Pole Motors:
Speed Control: Based on winding resistance.
Low Speed: Highest resistance.
High Speed: Least resistance.
Wiring: Connect line voltage to different points to select speed.
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