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Three Phase Emergency Lighting Inverter User’s Manual
#018-7002-00
1.6.D.
External Maintenance Bypass (EMB) Operation (Optional)
There is an optional External Maintenance Bypass which supplies the critical load with unconditioned
input power . The purpose of this option is to route power to the critical load while the UPS’ rectifier and
inverter are de-energized, and during Start-up before the system is fully operational (refer to Figure 4).
With the External Maintenance Bypass there is a hard wired bypass that can be operated after the Static
Bypass Switch has been operated, making it possible to isolate the entire UPS for service and mainte-
nance. The internal control system determines the operation of the normal and External Maintenance
Bypass paths, with the load powered from the inverter being the normal operation.
Figure 4 Single Line Drawings –External Maintenance Bypass Operation