| 摘要 |
PURPOSE:To maintain counter torque at minimum level by performing storage and discharge, through a reverse-connected diode, of magnetic energy into/from an exciting coil with high speed. CONSTITUTION:Upon power interruption, magnetic energy stored in an exciting coil K does not return to DC power supply because of a counterflow blocking diode 18 but charges a capacitor 19 through diodes 21a, 21b thus bringing the voltage thereof to a high level. Consequently, the magnetic energy disappears quickly and the current level drops. Since transistors 20c, 20d have been conducted already, voltage of the capacitor 19 is applied onto an exciting coil M thus rising the exciting current sharply. By such arrangement, production of negative torque and counter torque can be prevented. |
