| 摘要 |
PURPOSE: To reduce the price and size of an element-operation sensing device, by connecting respectively the three AC-voltage applying points of its three-phase rectification bridge comprising a plurality of diodes with the three-phase output points of an inverter device, and by providing a series circuit comprising a limiting resistor and photocoupler or a light transmitting transmitter between the common connection point of the anodes and anodes of the three- phase rectification bridge and the positive terminal of a DC power supply for the inverter device, and further, by providing another similar series circuit or similar transmitter between the common connection point of the anodes and cathodes of the bridge and the negative terminal of the DC power supply. CONSTITUTION: An element-operation sensing device 50 comprises two photocouplers (primary side photodiodes 51g, 51h and secondary side photodiodes 52g, 52h), two limiting resistors 53g, 53h, six diodes 56a-56f, two collector resistors 54g, 54h of the photocouplers, and a connection power supply 57. Further, in an element-operation deciding circuit 60, element-operation checks for semiconductor elements 2a, 2c, 2e of the positive side of an inverter main circuit 2 are performed by sensing the coincidence of the logical sum of respective ignition signals 4a, 4c, 4e of the semiconductor elements with an element-operation indicating signal 55g. Also, the element-operation checks for semiconductor elements 2b, 2d, 2f of the negative side of the inverter main circuit 2 are performed by the similar method to the foregoing one too. |
