INVERTER DEVICE FOR DRIVING ELECTRIC MOTOR

摘要

[PROBLEMS] An inverter for electric motor drive, suitable for an electric motor for fans and pumps and for en electric motor for driving motor vehicles. [MEANS FOR SOLVING PROBLEMS] An inverter device (4) for electric motor drive is constituted of two inverters, or an inverter (1) and an inverter (2), two electromagnetic contactors (43, 44), and one alternate operation control circuit (45). Usually, the inverter (1), the electromagnetic contactor (43) and the inverter (2), and the electromagnetic contactor (44) are alternately operated according to a command from the alternate operation control circuit (45) every time when a start switch (45a) and a stop switch (45b) are depressed, or alternatively, their operations are automatically alternated every 24 hours. As a result, their operation time periods are almost equal to each other, increasing operation reliability of the entire inverter device (5) and enabling power supply to an electric motor (3) to be continued even if either one fails.