| 摘要 |
PURPOSE:To protect the inverter by a method wherein a ractor suppressing the rate of rise of a short-circuit current and a resistor inserted at detecting an overcurrent are provided in the inverter device having a direct current power source small in internal impedance. CONSTITUTION:The DC power source is provided with the reactor 100 to which a diode 101 is connected in parallel inversely to the polarity of the power source and a resistor 102 to which a transistor 103 is connected in parallel, and the inverter is connected between output terminals 12 and 13. In normal operations, the transistor is ON and DC voltage is being applied to the inverter. At this time, if a load is shortened or a commutation is failed, the short-circuit current flows of which rate of rise is suppressed by the reactor 100, and if an output of an overcurrent detector 4 becomes larger than a reference voltage 105, the output of a comparator 104 causes the transistor 103 to be turned OFF and simultaneously, a relay 6 to be operated to turn an electromagnetic contactor 2 OFF. |
