Patent attributes
A motor control apparatus 1 that controls a rotation speed of a motor driven according to a speed command includes an abnormal-rotation detector 21 which determines that the motor is in an abnormal-rotation state, such as a runaway, when a speed deviation Ver obtained by subtracting a detection speed TSA of a motor rotation from a speed command VCMD is equal to or larger than a threshold value, when a sign of a product of acceleration ΔTSA obtained by subtracting a last detection speed from a detection speed this time that is detected in a predetermined cycle and a torque command Tc obtained by proportionally integrating the speed deviation is negative, and when an integration value VerSUM of the speed deviation Ver exceeds a predetermined value ALMlevel. With this arrangement, an abnormal rotation of the motor can be instantly detected even during acceleration or deceleration of the motor, thereby increasing the performance of protecting the motor.
