Patent ID: 7385367
Filing Date: 2008-06-10
Classification: H02P,Y10S

Abstract:
1. A motor control device comprising: a point value calculation unit for calculating a load point value based on a time ratio of an ON period of a power source voltage applied to a motor, a speed of the motor, and a power source voltage value such that the load point value calculated by said point value calculation unit changes according to a load of the motor and such that the load point value is a comprehensive value representing a combination of the time ratio, the speed of the motor, and the power source voltage value, said point value calculation unit being operable to calculate the load point value by referring to a load map in which the load point value is identified by parameters including the time ratio, the speed of the motor, and the power source voltage value arranged in a three-dimensional structure; a point value accumulation unit for accumulating each load point value calculated by said point value calculation unit to obtain an accumulated point value; a point value comparison unit for comparing the accumulated point value with a predetermined reference point value; and an instruction unit for performing an overload control process on the motor if the accumulated point value exceeds the reference point value.