| Abstract |
Mechanical switches using centrifugal force have been used for many years to actuate the switch in the auxiliary (start) phase of single phase induction motors. When the motor reaches a certain speed (cutout speed), the switch opens and disconnects the auxiliary winding or the start capacitor from the rest of the circuit. Should the speed decrease due to an overload and reach a certain cut-in speed, the switch is closed again. Even though the switch is very simple in principle, it has many disadvantages. This paper describes the development of a solid state switch which should have equal or better performance characteristics than the mechanical switch. Inherent properties of the motors which can be used for speed indication are reviewed and experimental results are presented. |
