| 摘要 |
PROBLEM TO BE SOLVED: To provide a dynamic brake circuit having a function to detect a failure thereof during the operation of a motor. SOLUTION: The dynamic brake circuit comprises a brake 106 that includes a rectifier circuit 101 for rectifying a motor driving signal, a resistor 102 connected in series between both terminals of the rectifier circuit 101, and a c-contact relay 103, a monitor circuit 104 that outputs a monitor signal, and a failure determination circuit 105 for determining whether the brake 106 has failed based on the monitor signal. One end of the monitor circuit 104 is connected to an NO terminal 103c that is short-circuited with a COM terminal 103a of the c-contact relay 103 at a normal time during the operation of the motor. The monitor circuit 104 detects a change in voltage in compliance with the motor driving signal and outputs it as a monitor signal. The failure determination circuit 105 determines that the brake 106 has failed when a pattern of the monitor signal is different from that in a normal situation. COPYRIGHT: (C)2011,JPO&INPIT
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