A theory of the operation of cylindrical induction motors with squirrel-cage rotors

The electric and magnetic field vectors in the air-gap of an induction machine are derived from a scalar potential which satisfies Laplace´s equation; the application of boundary conditions at the stator and rotor surfaces then leads to a complete knowledge of the air-gap field and the rotor current in terms of stator current. All the electric and magnetic quantities can be expanded in a series of travelling harmonics, each of which produces its own component of torque and rotor I2R loss. The pulsating component of torque is the only derived quantity which depends upon interaction between harmonics. The general theory is applied to the polyphase machine, the singlephase machine and the 2-phase servo-motor; in each case the result conforms with accepted theory. The theory could well be applied to machines with unusual stator windings.