Operating Procedures
6.5Powering Down the UPS and Maintaining Power to Load
NOTE
An external Maintenance Bypass Cabinet must be installed before attempting to perform the following procedure
If the UPS needs to be shut down completely while maintaining power to the load, follow these steps:
1.Perform Steps 1 through 5 in 6.3 - Switching the UPS from Normal to Maintenance Bypass.
2.Close the external maintenance bypass rotary switch to Maint position.
! WARNING
On the primary input distribution panel, which is often located distant from the UPS area, a label should be posted advising service personnel that the UPS circuit is under maintenance.
! WARNING
Wait 5 minutes for the internal DC busbar capacitors to discharge.
The UPS is now completely powered down.
NOTE
The maintenance bypass power switch may be operated at any time while the UPS is powered down to connect the load to the maintenance bypass supply if required
The procedure can be performed only after the installation has been completed (which includes the maintenance bypass cabinet), after the system has been placed in operation by authorized personnel. See Figure 30 for more information.
Figure 30 Example of configuration for single UPS with external maintenance bypass cabinet.
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3P
49