APC Smart-UPS VT - Manual (Page 12)

6 Smart-UPS® VT 10-40 kVA 400V, 208V, 200V – Operation 990-2282A-001
Operation
Operation Modes
The UPS has different operation modes. If the installation includes a Maintenance Bypass Panel
(MBP), an external maintenance bypass operation mode will also be available.
Normal operation
The UPS converts utility/mains power to conditioned power for the connected load.
Battery operation
The UPS provides power to the connected load from its internal and (if available) external batteries
for a finite period. The UPS transfers to battery operation if the supply of utility/mains power fails, or
is outside the pre-defined limits.
Internal bypass operation
Internal bypass keeps the load supplied with utility/mains power during maintenance of the UPS
power sections. In internal bypass operation, utility/mains power is sent directly to the connected
load bypassing all internal UPS functions and filters. Battery back-up is not available in internal
bypass operation even though the batteries are in place.
External maintenance bypass operation
The UPS can be connected to an optional external MBP. When activated, this panel bypasses the entire
UPS enclosure, feeding utility/mains power directly to the load. An activated external MBP completely
isolates the UPS and allows maintenance to be performed. An external MBP is mandatory if the UPS is
running in parallel.
Optional parallel operation
The connected load is powered by multiple UPS units to increase system redundancy or to increase
power. The internal mechanical bypass lever is not available.