Powerware 9155 2.The UPS automatically shuts down, Turn the Maintenance Bypass switch to the SERVICE position, 3.Switch the UPS battery circuit breaker to the ON position

UPS Maintenance

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 UPS 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 breaker 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 UPS 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.

Powerware® 9155 UPS (8–15 kVA) User’s Guide S 164201553 Rev D www.powerware.com 81