American Power Conversion 480kW400V - Manual (Page 16)

16 User Guide APC Silcon 480kW 400V UPS
990-4058
Stop/Start UPS and Operating the External Service Bypass
2.7 Isolating one UPS in a Parallel Configuration for Service/Maintenance
2.7.1 Isolating one UPS in a Parallel/Redundant System
In a redundant system one UPS may be isolated for service/maintenance without affecting
other parallel UPS(s).
2.7.2 Switching Back the UPS to Normal Rarallel/Redundant Operation
The UPS will automatically switch to normal operation and start load-sharing with the other
parallelled UPS(s).
Service
bypass
switch
Load Mains
APC Silcon
UPS
APC Silcon
UPS
Action
1. Check that the remaining UPS(s) will be able to carry the load when one UPS is isolated.
2. Switch off the system to be isolated for maintenence by pushing the green ON and the red
OFF button simultaneously.
3. Disconnect output and mains by setting output switches (Q002) to position 0 and input
switch (Q001) to position 0. Disconnect battery by opening battery breaker.
Action
1. Set the input switch (Q001) and the output switch (Q002) to position 1.
2. Charge capacitors, connect battery, and start up the UPS as described in 2.4.1. Start UPS
(from complete power down).
WARNING!
The system will discharge built-in capacitors.
ALWAYS check with a multimeter that the terminals contain no dangerous voltage before
touching the system!