| 摘要 |
PURPOSE:To miniaturize a brake coil and a diode circuit of a three-phase induction motor with a brake by inserting a brake coil through a rectifier circuit to one side of a delta-connection of the armature windings of the motor to excite it with phase current. CONSTITUTION:When a power supply is thrown, a starting current is flown through armature winding 2, and a brake coil 5 wound on a stationary iron core is excited by a DC current I3 produced by rectifying the current flown through the winding 2 by a full-wave rectifier circuit 7. A movable iron core (not shown) is attracted against the tension of a brake spring to release a brake to allow the motor to start to continue operation. The current I3 flown through the brake coil 5 becomes substantially equal to the current I1 flown at Y-connecting winding. When the power supply is opened, the current of the brake coil 5 is eliminated to brake the motor to stop the motor. Since the brake coil is excited by the phase current when the delta-connected winding is operated, this motor can be designed to miniaturize the electric parts such as brake coil, diode circuit or the like used for common delta- connected circuit and Y-connected circuit. |
