Service manual

Always On UPS Systems
M0704_NX_Series_Service_Manual V2.17 2012-06-12 18
This fuse holder or breaker can be located within the UPS system or within
the battery cabinets.
c. Open the Rectifier breaker – Opening the rectifier breaker will take the
power source away from the DC bus, therefore, the DC bus will start to drop
slowly. After 5 min., the DC bus will drop to a safe level (approx. 20VDC).
d. Close the Bypass breaker – The reserve breaker and reserve static switch
are still conducting. When the maintenance bypass breaker is closed, power
will flow through the bypass loop instead of the reserve loop because the
impedance of the bypass loop is lower.
e. Open the Reserve breaker – You can now open the reserve breaker to put
the ups into manual bypass.
NOTE: To place the unit into Maintenance Bypass mode the fuse holders behind the
control module (where all control PCB’s are stored) must be opened.
The system is now in Manual Bypass mode (or Maintenance Bypass mode).
CAUTION!
If fuse holders have not been opened power is still present and fans will be turning. If
fuse holders are open power is still present at the terminal strip and several terminals on
the PCB’s