| 摘要 |
PROBLEM TO BE SOLVED: To form a DC electromagnetic brake in one surface brake type compact in an axial direction and economical, capable of corresponding even to enlargement in size of an electric motor, simplify a control circuit, decrease the cause of trouble, and also simplify wiring work. SOLUTION: A coil 17 of a brake electromagnet 16 is constituted with two coils 17a, 17b of different resistances, an FET31 is conducted by an electric motor starting current through a switch circuit 35 utilizing a search coil 30 detecting an electric motor current, for instance the FET31, a full-wave bridge rectifying circuit 36, and a diode 37, a full-wave rectified current flows in the coil 17a of small resistance, and a brake is released by generating a large magnetic attraction force. After starting, the electric motor current is decreased, a half-wave rectifying circuit is formed by interrupting the FET, and a halved current flows in a DC circuit of the two coils 17a, 17b, so as to lower magnetic attractive force to only maintain a brake release.
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