Eaton Power Xpert 9395C Installation And Operation Manual

92 Eaton Power Xpert 9395C UPS Installation and Operation Manual 164000821—Rev 0666..22..66 MMaaiinntteennaannccee BByyppaassss MMooddeeThe critical load is not protected from voltage or frequency fluctuations or power outages while the UPS is inBypass mode.A maintenance bypass switchboard is used with the UPS to bypass the UPS system when maintenance isrequired. The switchboard includes a maintenance isolation circuit breaker (MIB) and a maintenance bypasscircuit breaker (MBB).A Solenoid Key Release Unit (SKRU) is utilized in a key interlock scheme between the MIB and MBB breakers.A load bank breaker (LBB) is also provided and is interlocked with the MIB breaker. See the following transfersequences for transferring the critical load to and from maintenance bypass and the UPS system to and fromthe load bank.The maintenance bypass switchboards also contain module output breakers and various load distributionbreakers. Please see the switchboard as-built drawings for details.NOTE The breaker names for the maintenance bypass switchboards used at the CYS01location use MB02 and MB03 in place of MBB and TB01 in place of MIB.66..22..77 TTrraannssffeerr ttoo MMaaiinntteennaannccee BByyppaassss aanndd LLooaadd BBaannkk SSeeqquueenncceeKey Operation: Transfer UPS system to Maintenance Bypass1. Place the UPS in Bypass mode. See the applicable UPS Operation/Installation manual for details ontransferring the UPS to Bypass mode.NOTE Key K-MB cannot be released from the SKRU until the UPS is in Bypass mode. Once keyK-MB is turned and released from the SKRU, the UPS transfer to normal (On Inverter)will be inhibited.2. Verify that the ENABLE light on the SKRU is illuminated. Turn and release key K-MB from the SKRU lock.3. Insert key K-MB into the MBB breaker lock. Turn key K-MB to unlock the MBB breaker. Close the MBBbreaker.4. Open the MIB breaker. Turn and remove key K-UO form the MIB lock and insert it into SKRU lock. TheUPS is now in Maintenance Bypass mode. The critical load is supported by the maintenance bypasssource.NOTE The critical load IS NOT supported while in Maintenance Bypass mode.Key Operation: Transfer UPS system to Load Bank1. Verify the UPS has been transferred to Maintenance Bypass mode. See previous procedure.2. Remove key K-LB from the MIB breaker. Insert key K-LB into the LBB lock.3. Verify key K-ML is in the LBB breaker lock. If not present, remove key K-ML from one of the other LoadBank breakers common to the system Load Bank and insert into the LBB lock.NOTE Multiple systems share a common load bank. A single K-ML key is used to prevent morethan one system from being connected to the load bank at a time. Key K-ML must beinserted in the Load Bank breaker lock of the system to be connected to the load bank.4. Turn key K-LB to unlock the LBB breaker. Close the LBB breaker.Understanding UPS Operation