POWER CONVERSION EQUIPMENT

To provide a power conversion equipment which can detect short circuit failure of series connected capacitors of a smoothing capacitor circuit 4. A capacitor failure detecting circuit is composed of the combination of switch units 7SW, exciting resistors 8R, contact resistors 9R, and diodes 10D. The switch unit 7SW is provided with an exciting circuit and a contact circuit, and when a predetermined current flows through the exciting circuit the contact circuit is closed. The exciting circuit of the switch unit 7SW and the exciting resistor 8R are alternately connected in series, and the contact circuit and the contact resistor 9R are alternately connected in series, corresponding to the number of the series connected capacitors, and these series circuits are connected in parallel with the capacitors. A connecting point of the exciting resistor 8R and a next switch unit and a connecting point of the contact resistor 9R the next switch unit are connected, and the diode 10D is connected from this point to a connecting point corresponding to the capacitor. When the excitation of the switch circuit 7SW having a lowest potential is turned OFF, it is judged that at least one of the series connected capacitors has failed by short circuit.