| 摘要 |
PURPOSE:To protect a motor against a defect or a breakdown due to idling of the motor by judging the state of a power element of a deflective inverter, thereby deciding the power element to be applied with a brake current in response to the state. CONSTITUTION:If one, e.g., 22a of overcurrent detection signals 22a-22f is output due to an overcurrent detection in a controller of an inverter, an SCR112 is turned ON, 23a of base block signals 23a-23f becomes zero voltage, and the base drive signal of a power transistor of an inverter is base-locked. A microprocessor calculator 101 inputs the state of the anode voltage of a thyristor by an input port 115, searches a power transistor which generates an overvoltage detection signal to judges the cause of the overvoltage. Then, a power element to be applied with a brake current is decided in response to the state. |
