This so-called passive redundancy protects against the total failure of the voltage supply on the secured busbar; however, in this operating mode, mains faults would directly affect the load. As a result, the electronics continuously attempt to switch back to "online" / normal operating mode (e.g. when the overload or overtemperature goes away).
The bypass consists of an inverse-parallel thyristor stack and functions as an extremely rapidly switching link between a load and the mains. The synchronization unit ensures that the frequency and phase of the inverter voltage is synchronized with the mains and can therefore be switched over without interruption (within the tolerance limits).
The bar graph LED functions as the display of i the UPS capacity utilisation. The acoustic signal sounds every 2 seconds during this operating
mode.
6.1.4Manual Bypass