Powerware 9155 - Page 87

UPS Maintenance
81
Powerware
®
9155 UPS (8–15 kVA) User’s Guide S 164201553 Rev D www.powerware.com
To switch the UPS to maintenance bypass from Normal mode
(UPS -mounted operation):
1. Turn the Maintenance Bypass switch through the SERVICE
position to the BYPASS position.
The battery circuit breaker trips, and the UPS is now bypassed,
with the load powered by utility power.
2. The U PS automatically shuts down.
To return to Normal mode from maintenance bypass (UPS-mounted
operation):
1. If an optional isolation transformer is installed, switch the input
circuit b reaker to the ON position.
NOTE The isolation transformer output is always 240V (180° phase
angle). Any equipment connected to the output requiring 208V (120° phase
angle) is at risk for damage.
2. Turn the Maintenance Bypass switch to the SERVICE position.
The U PS starts up in Bypass mode, with the load still powered
by utility power.
3. Switch the UPS battery circuit breaker to the ON position.
NOTE Wait until the indicator illuminates before proceeding to
Step 4; otherwise, power to the load may be lost.
4. Turn the Maintenance Bypass switch to the UPS position to
return to Normal mode. The UPS is now powering the load.