Liebert UPStation S VM18000 - Manual (Page 19)

19
Test
When the rotary switch is placed in the Test position, contacts A and B are closed and C is open. The
power for the load is now coming from the maintenance bypass source, as illustrated in below. The
connection from the output of the UPS is open. Input power to the UPS is still available for testing and
troubleshooting purposes.
Maintenance
When the rotary switch is placed in the Maintenance position, contacts A and C are open and B is closed.
The power for the load is coming from the maintenance bypass source, as illustrated below. The UPS is
now completely isolated from the source as well as the critical load.
UTILITY
FEED
CRITICAL
LOAD
MAINTENANCE BYPASS
UPStation S™
BATTERIES
BYPASS
BYPASS
INVERTER PFC
A
B
C
UTILITY
FEED
CRITICAL
LOAD
MAINTENANCE BYPASS
UPStation S™
BATTERIES
BYPASS
BYPASS
INVERTER PFC
A
B
C