| 摘要 |
PROBLEM TO BE SOLVED: To solve the problem raised by the conventional technology that a process, such as charging the filter capacitor of a main circuit at a low voltage, and so on, which is not performed in the normal operation of a servo motor must be performed before the motor is normally operated. SOLUTION: A dynamic brake circuit has a serially connected circuit of a resistor 15 which converts the electric energy of a load into heat and a semiconductor switching element 14 and a snubber circuit 18 containing a capacitor 17 connected in parallel with the switching element 14. The brake circuit is also provided with a charging circuit which charges the capacitor 17 before driving the load and a voltage detecting and insulating section 25 which insulatively transmits a signal to a control section 24 upon detecting that the capacitor 17 is charged to a fixed voltage or higher. The control section 24 detects the abnormal conditions of the braking resistor, rectifier, etc., of the dynamic brake circuit before starting the normal operation of the servo motor from the presence/absence of the charged voltage of the capacitor 17 of the snubber circuit 18.
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