Patent ID: 7550940
Filing Date: 2009-06-23
Classification: H02H

Abstract:
1. An overload current control circuit for a DC motor comprising: a DC motor, a DC power source, a power semiconductor assembly, and a sampling resistor being connected together, the overload protection and detection circuit serving to turn on and off the DC motor by using the power semiconductor assembly; characterized in that: the overload current control circuit further comprises a voltage polarity switching circuit and a power semiconductor assembly control circuit, the overload protection and detection circuit is connected to the voltage polarity switching circuit and the power semiconductor assembly control circuit, respectively, the polarity switching circuit is connected to the sampling resistor, the power semiconductor assembly control circuit is connected to the power semiconductor assembly, the voltage polarity switching circuit controls single polarity of a sampling voltage of the sampling resistor, so as to supply constant voltage potential to the overload protection and detection circuit, thus providing overload protection to the DC motor through the power semiconductor assembly control circuit.