Powerware 9315 - Manual (Page 42)

36 Powerware 9315 Parallel Redundant System I & O
164202013, Rev. D 041599
How to Isolate a Module
The primary function of the MOBs is to allow isolation of a module for maintenance
or service. In parallel operation, each module becomes the other’s maintenance
bypass source.
Do not attempt to isolate a module until it is assured that the redundant module
can support the critical load. The best assurance is if the redundant UPS module’s
designated MOB is closed and the OK TO CLOSE lamp is illuminated.
As an alternative:
1. Make sure the designated MOB for both modules is closed.
2. Place the UPS module to be isolated in Bypass mode.
3. Place the redundant module in Bypass mode.
4. Open the designated MOB of the UPS module to be isolated.
When a module’s designated MOB is open, it will work like a standard Reverse
Transfer module as described in the PowerwareÒ 9315 Operation manual provided
with the UPS system. The MOB should only be closed when its OK TO CLOSE
lamp is illuminated.
Shut Down a Module
To turn a module off, place its mode switch to the Bypass position and open its
circuit breaker (CB1).
Transfer System to Bypass
To place the system in Bypass mode:
1. Turn the mode switch on both UPS modules to the Bypass position. The first
module will shut off its inverter and the redundant module will transfer to
Bypass.
To place both UPS modules on Bypass:
1. Turn the mode switch on both UPS modules to the Bypass position.
2. After the first module shuts off and the redundant module is in Bypass, activate
the start switch on the first module with the mode switch still in the Bypass
position.
To transfer both UPS modules from Bypass mode to Normal mode:
1. Turn the mode switch on both modules to the Normal position.
2. Activate the start switch on either UPS module.