INVERTER CONTROLLER

PURPOSE:To suppress an abnormal influence by checking the function of a semiconductor switching element of an inverter main circuit reverse conversion section at the time of tripping function operation and prohibiting the later resetting when an abnormal event is detected. CONSTITUTION:A servo-inverter device converts 3-phase AC power into DC power by diode module 7 of a forward conversion section C, and it is converted into 3-phase AC power again by a reverse conversion section 1, and is supplied to an AC motor 13 of a load. This state of driving is taken into a controller 10 by possessing an encoder 14, and a control signal A of the reverse conversion section I is outputted. A base driving circuit 11, a control circuit 12, a switching- over switch 15, and voltage dividing resistors 16-17 are provided to the control ler 10, and the base signal amplifier circuits A1-A6 corresponding to each of transistors 1-6 of said driving circuit 11 are also provided. The resetting is prohibited only in case the cause of a tripping is a permanent abnormality by the breakdown of the element.