Rotating stator field induces rotor current; slip enables torque.
A rotating stator field induces rotor currents; torque arises since the rotor lags by slip s=(N_s-N)/N_s. Typical full-load slip 2–5%. Squirrel-cage rotors are rugged and cheap; wound rotors allow external resistance. Torque-speed curve has a breakdown peak.
A 4-pole 50 Hz motor runs near 1450 rpm.
Induction motors are the most common motors in industry because they are rugged, cheap and need no brushes.
Rotating stator field induces rotor current; slip enables torque.
Induction motors are the most common motors in industry because they are rugged, cheap and need no brushes.
The difference between synchronous speed and rotor speed, expressed as a fraction of synchronous speed, and it must be positive for torque to be produced.
The rotor current is induced by the rotating stator field, so no electrical connection to the rotor is needed.
Typical applications include driving a pump with a three-phase induction motor, explaining why an air compressor motor draws a high starting current and choosing a motor for a fan in a building ventilation system.
Study "DC motor types" first (topic 59 of 106 in Electrical Engineering). It covers the groundwork this topic builds on.
N_s=120f/P. Starting current 5–7× rated. Most widely used industrial motor.
A 4-pole 50 Hz motor runs near 1450 rpm.
The next topic is "Synchronous machines", which builds directly on this one.
It is classed as Intermediate in Electrical Engineering (topic 60 of 106). It is an intermediate topic. Work through the beginner topics in Electrical Engineering first.
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