Patent ID: 7800872

Claim:
A switch-state monitoring device for a switch that opens and closes a main circuit by use of a motor, the switch-state monitoring device comprising: an operating time measuring means for detecting an operating time for the motor when the switch is opened or closed; a first determination means for comparing an operating time for the motor detected by the operating time measuring means with an continuous-operating-capable setting time for the motor and determining whether or not the operating time for the motor has exceeded the continuous-operating-capable setting time; a protection means for halting energization for the motor, in the case where, based on an output of the first determination means, it is determined that the operating time for the motor has exceeded the continuous-operating-capable setting time; a second determination means for determining whether or not the operating time for the motor detected by the operating time measuring means has fallen outside an setting range with which it is determined whether or not an abnormality exists in the switch; and an output means for outputting an abnormality in the switch in the case where, based on an output of the second determination means, it is determined that the operating time for the motor has fallen outside the setting range.