Patent ID: 7612513

Claim:
A motor control device, comprising: a position detecting sensor detecting an angular position of a motor; a speed controller controlling a speed of the motor based on the angular position of the motor detected by the position detecting sensor; a temperature estimation component that estimates a temperature of the motor from a current command value or a torque command value and, when the estimated temperature reaches a threshold, outputs a current cutoff signal to a current controller that cuts off passage of current to the motor; and an operational state determination component determining based on the angular position of the motor detected by the position detecting sensor that the motor is in a locked state when the angular position of the motor does not change and that the motor is in a rotating state when the angular position of the motor changes, wherein the temperature estimation component sets the threshold as a first threshold when it is determined by the operational state determination component that the motor is in a rotating state and sets the threshold as a second threshold, which is smaller than the first threshold, when it is determined by the operational state determination component that the motor is in a locked state.