Patent ID: 8299740
Filing Date: 2012-10-30
Classification: E05F,E05Y

Abstract:
1. A motor drive apparatus for driving a motor in a normal rotation direction or a reverse rotation direction in accordance with a state of operation of an operation switch, the motor drive apparatus comprising: a first semiconductor switching device that switches ON/OFF state based on a normal rotation instruction provided by the operation switch; a second semiconductor switching device that switches ON/OFF state based on a reverse rotation instruction provided by the operation switch; a control circuit for controlling drive of the motor in the normal rotation direction or the reverse rotation direction, based on the ON/OFF state of the first and second semiconductor switching devices; and a wetting detection circuit for detecting wetting and controlling operation of the first and second semiconductor switching devices, wherein the control circuit includes: wherein the wetting detection circuit comprises a third semiconductor device that turns ON when wetting is detected, wherein, when the wetting detection circuit detects wetting and when the normal rotation instruction and the reverse rotation instruction are not provided by the operation switch, current flows from a power supply to both of the first semiconductor switching device and the second semiconductor switching device via the third semiconductor switching device, and both of the first semiconductor switching device and the second semiconductor switching device turn ON, whereby voltage values of the first terminal and the second terminal are less than the reference voltage value, wherein, when the wetting detection circuit detects wetting and when the normal rotation instruction is provided by the operation switch, current flows from the power supply to only the second semiconductor switching device of the first and second semiconductor switching devices via the third semiconductor switching device, and only the second semiconductor switching device of the first and second semiconductor switching devices turns ON, whereby the voltage value of the first terminal is more than the reference voltage value, wherein, when the wetting detection circuit detects wetting and when the reverse rotation instruction is provided by the operation switch, current flows from the power supply to both of the first semiconductor switching device and the second semiconductor switching device via the third semiconductor switching device, and both of the first semiconductor switching device and the second semiconductor switching device turn ON, whereby the voltage values of the first terminal and the second terminal are less than the reference voltage value, and wherein the first terminal and the second terminal are separated from the high level terminal, and are arranged in proximity to the low level terminal.