APC SYMMETRA PDUM160H-B - Manual (Page 13)

990-3015-001 Symmetra PX 160 kW 400 V Operation 7
Operation
Operation Modes
In an installation without a maintenance bypass panel, the UPS has four different operation modes. If
the installation includes a PDU-XR or an external maintenance bypass panel, wrap-around
maintenance bypass mode will also be available.
Normal operation
During normal operation, the UPS converts mains/utility power to conditioned power for the
connected loads.
Battery operation
During battery operation, the UPS provides power to the connected loads from its external batteries
for a finite period. The UPS transfers to battery operation if the supply of mains/utility power fails, or
is outside pre-defined limits.
Bypass operation
Bypass is a feature that keeps the load supplied with mains/utility power during maintenance of the
UPS power sections. In bypass, mains/utility power is sent directly to the connected load bypassing
all internal UPS functions and filters. Battery back up is not available in bypass operation.
Wrap-around maintenance bypass (optional)
The UPS can be connected to a PDU-XR or an optional external maintenance bypass panel. When
activated, this panel bypasses the UPS, feeding mains/utility power directly to the load. An activated
wrap-around maintenance bypass panel completely isolates the UPS and allows maintenance to be
performed - including a replacement of the entire UPS.