Patent ID: 7061204
Filing Date: 2006-06-13
Classification: H02P

Abstract:
1. A motor starter device for use with a motor having a main winding and a start winding, comprising a positive coefficient of temperature (PTC) thermistor connected in series with the start winding, a triac connected between the PTC thermistor and a power source line and a triac control circuit connected in series with the start winding and said main winding and connected to the gate terminal of the triac, the triac control circuit supplying voltage to the gate terminal that is in conformity with the incoming circuit current at the time of the startup of the motor and making the triac conductive at the time of the motor startup, said triac control circuit further comprising a current detecting circuit that detects the incoming circuit current and a voltage generating circuit that produces voltage on the basis of the current that has been detected by the current detecting circuit, said current detecting circuit comprising a current transformer that includes a primary winding connected in series with the power source line and a secondary winding, the current transformer produces the electric current that has been converted from the secondary winding side through the selection of the winding number ratio between the primary winding and the secondary winding and the voltage generating circuit includes a resistor that is connected in parallel with the secondary winding and supplies the voltage that is obtained from the resistor to the gate terminal.