| 摘要 |
PURPOSE: To bring out torque to the utmost and to protect a circuit safely by practically reducing motor exciting current to be caused to flow by a drive means, by the increase of DC voltage outputted from a converting means, when the number of revolution of the motor is smaller than a specified value, or it is in a state of being locked. CONSTITUTION: A drive means 1 for revolving a motor and a revolution detecting means 2 for detecting the number of revolution or the motor are provided. Besides, a rotational signal outputting means 3 for outputting a signal corresponding to the number of revolution of the motor on the basis of the detection signal of this detecting means, and a converting means 4 for converting this signal output to a DC voltage are provided. And a dead time controller 5 is provided to reduce the exciting current of the motor through the medium of the drive means 1, when the number of revolution of the motor is smaller than a specified value or it is in a state of being locked. Concerning to the voltage of a signal obtained by the DC converting means 4, its DC voltage increases, when the number of revolution of the motor is abnormal or the motor is locked. Consequently, pulselike exciting current is caused to flow and the effective power is lowered. |
