It can also happen that the maximum output current of the inverter is lower than the minimum current for keeping the fault arc burning. The fault arc is quenched “automatically” than without the intervention of a short-circuiting switch and a circuit breaker. In this case, the hazardous situation is simply cleared by the current limitation of the inverter. As a consequence, the electrical appliance can move over to normal operation again almost immediately.

The override input of the UPS may be connected to the control unit for closing the bypass switch between the UPS input and the UPS output so that it is inhibited from being closed indirectly. In this way, the control unit may take further considerations and close the switch despite an active override signal under certain circumstances. However, the override input of the UPS may alternatively be connected with the bypass switch so that it is directly inhibited from being closed. That means an active override signal keeps the switch open anyway.

The term “activated” in the above context does not necessarily imply a positive signal, but the bypass switch may also be kept open by a negative signal or the absence of a signal. For example, a positive signal is sent to the override input in case of a fault arc if a positive signal keeps the bypass switch open, and a negative signal is sent to the override input in case of a fault arc if a negative signal keeps the bypass switch open. Other signal types may be applicable as well, for example, AC signals or binary signals.