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10.7 De-Energize Liebert
®
APM
™
Without Maintenance Bypass Cabinet
To de-energize the APM:
1. On the UPS control panel, press and hold the INVERTER OFF button for 2 seconds.
2. Open all battery circuit breakers(s) including internal battery breaker (if applicable).
3. Open the UPS output circuit breaker(s).
4. Open the UPS input circuit breaker and bypass circuit breaker (dual input systems only).
5. Allow 5 minutes for all DC circuits and capacitors to fully discharge.
6. Use a digital multimeter to verify there is no AC or DC voltage present at the UPS input, output
and bypass bus bars.
Figure 64 Typical configuration for single UPS
10.8 Switching the Liebert
®
APM
™
from Parallel to Single UPS Operation
10.8.1 Procedure to Take UPS1 Offline While Leaving UPS2 Online
The procedure below is used to switch the system from parallel to single UPS operation.
NOTICE
Risk of improper switching. Can cause damage to connected load.
!
CAUTION
This procedure will remove power from the critical bus.
!
CAUTION
Performing the next step will shut down the critical load.
Field-Supplied Wiring
Notes
1. Install in accordance with national and local electrical codes.
2. A neutral is required from the system AC input source.
A full-capacity neutral conductor and grounding conductors
are recommended.
3. UPS system input and output cables must be run in separate conduits.
4. Control wiring must be run in separate conduits.
5. Customer must supply shunt trip breaker with 120V coil.
UAM01000
Rev. 2
* System AC Input
4-Wire + GRD
See Note 5
AC Output
208V
4-Wire + GRD
* External Overcurrent
Protection by Others
Static Bypass
Output
Busbar
UPS Cabinet
Battery