| 摘要 |
PURPOSE:To enable precise control by a method wherein impedance of an exciting coil to specific measuring high-frequency current is determined and transmission torque is estimated. CONSTITUTION:If a switching element 6 is switched in a prescribed duty factor and current from a DC power source 5 flows through an exciting coil 4, eddy current is produced within a rotary disc 2 disposed in magnetic field across a yoke 3 and brake torque of a rotary shaft 1 is generated. On the other hand, an impedance bridge 12 having the exciting coil 4 as one side is installed, and impedance is determined to high-frequency current supplied from a high-frequency power source 121 through a high-frequency transformer 122 to the exciting coil 4. The transmission torque of the electromagnetic brake is determined based on the impedance. A control circuit 16 controls pulse generated by a pulse generator 7 corresponding to the determined transmission torque, and controls the switching time of the switching element.
|
