Emergency Power Off (EPO)
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| Illustration 1 | g02345901 |
Power components | |
Note: The fuses shown in Illustration 1 protect the UPS against catastrophic rectifier and inverter semiconductor failure. These failures can be caused by the normal AC source or by the load.
Normal AC input (30) - Three-phase 480 VAC 60 Hz line voltage utilized in Normal operation to support the load.
Bypass AC input (31) - Three-phase 480VAC 60Hz line voltage utilized in Bypass or Maintenance operations to support the load.
Q1 (32) - Molded circuit breaker used to Isolate the rectifier/charger (A) from the normal AC source (30)
Rectifier/charger module (A) - This module converts three-phase AC power from the normal AC source supply (30) into DC power for the normal inverter (B) input. This module float charges or recharges the battery (D) .
Inverter module (B) - Converts the DC power supplied by the rectifier/charger module (A) or the battery unit (D) into three-phase AC power for the load
Q5N (33) - Switch that can isolate the UPS system from the load
QF1 (34) - Circuit breaker for battery (D) protection and isolation
Battery unit (D) - The battery unit provides backup power for the inverter (B) in the event of a voltage drop or a normal AC input (20) failure.
Static bypass module (C) - This module ensures the instantaneous transfer of the load to the bypass AC source input (31) in the event of an inverter (B) shutdown. The shutdown can be initiated by the user, a protective device, or a sudden load.
Q4S (36) - Switch that isolates the static bypass (C) from the bypass AC source input (31)
Q3BP (35) - This switch isolates the UPS for maintenance. During maintenance the Q3BP transfers the load to the bypass AC source input (31) without interrupting the supply of power.
Note: The normal AC input and the bypass AC input have different functions. Depending in the installation, each input may be protected differently upstream and/or come from different sources.
The UPSB220 provides internal contacts for Remote Emergency Power Off (REPO) connections.
ReferenceRefer to Operation and Maintenance Manual, "Component Description" for wiring location.
Wire the REPO connections from a customer provided mushroom-head type emergency-off push button. The REPO button is only to be used in an emergency to stop UPS operations. Pressing the REPO button also causes the following actions:
- Turns off the rectifier/chargers and inverters
- Opens the input circuit breaker (Q1) on the normal source
- Opens the battery circuit breakers (QF1)
- Opens the backfeed protection contactor (K4S) on the bypass AC source
- Blocks the static switches
- Activates a contact on the Media Contacts 11 board (terminals 1 to 3 on connector XR4)
If the REPO is utilized, the push-button contact must be reset prior to restarting the UPS unit.
Note: In parallel configurations, there must be a single button for shutdown with a separate contact for each UPS unit.
- Open the Mains 2 feed switch Q4S (36) .
- Open the Output Isolation switch Q5N (33) .
- Follow the single UPS startup procedure to start up the system.