Uninterruptible power supply device

An uninterruptible power supply device comprising:

• a converter that converts AC power from an AC power supply into DC power;
• an inverter that converts the DC power generated by the converter or DC power in a power storage device into AC power and supplies the AC power to a load;
• a switch connected between the inverter and the load;
• an electromagnetic contactor that is connected between the AC power supply and the load, and is turned on during bypass power feeding in which the AC power is directly supplied from the AC power supply to the load;
• a control device that controls the switch and the electromagnetic contactor such that the switch is turned on and the electromagnetic contactor is turned off during inverter power feeding in which the AC power is supplied from the inverter to the load, and the switch is turned off and the electromagnetic contactor is turned on when the inverter has a failure,
• the electromagnetic contactor being turned on when a contact is closed by excitation of a coil according to a control signal from the control device, and having a manual switch that can close the contact by being pressed from outside;
• a pressing force applying mechanism that applies a pressing force to the manual switch;
• and
• a control circuit that operates the pressing force applying mechanism when there occurs a failure that the electromagnetic contactor cannot be turned on regardless of the control signal from the control device,
• the control circuit operates the pressing force applying mechanism when first to third conditions are satisfied,
• the first condition is that the inverter power feedinn cannot be performed and there is detected a failure that the electromagnetic contactor cannot be turned on,
• the second condition is that both the switch and the electromagnetic contactor are turned off, and
• the third condition is that another uninterruptible power supply device is not connected to the load in parallel with the uninterruptible power supply device. or that, when the other uninterruptible power supply device is connected, the other uninterruptible power supply device does not supply power to the load.