Method of Starting and Running a Single Phase Induction Motor
Original Publication Date: 1981-Jun-01
Included in the Prior Art Database: 2005-Feb-11
A sine-wave drive to the run winding of a single-phase induction motor is generated by using an oscillator output to address a read-only memory (ROM) in which a sine-wave profile is stored. Mains AC is applied to a start winding of the motor, and the oscillator is synchronized with the mains in a phase-locked loop. By preloading the ROM addressing circuit a predetermined phase shift with respect to the mains can be achieved so that a rotating magnetic field is created to start the motor.