Low-speed brushless alternating-current motor

Following the discovery that a steel rod can be made to roll along the surface of a linear induction motor in the same direction as that of the travelling magnetic field, the phenomenon was investigated with a view to the development of a low-speed high-torque brushless a.c. motor. It was found that the torque was increased when the rod rolled at an angle to the direction of the field. The paper describes the development of a rotor motor using these principles in which the stator winding is conventional, except that the slots are very heavily skewed to make use of the angled-field effect. Some initial theoretical calculations are included.