Emerson 400V, 50 and 60 Hz External Maintenance Bypass Cabinets, Interlock with UPS Module

External Optional Cabinets

4.0EXTERNAL OPTIONAL CABINETS

4.1External Maintenance Bypass Cabinets

The bypass cabinet enables maintenance operations and repairs to be performed in full isolation while also allowing the disabling of each UPS without affecting the ordinary operation of the system (depending on the redundancy level).

The optional maintenance bypass cabinet must be used in all configurations where one internal main- tenance bypass switch is insufficient to supply the full system load.

Each kVA rating has maintenance bypass cabinets sufficient to supply the full system load up to six units in parallel power operation.

4.2Interlock with UPS Module

Interlock the External Maintenance Bypass Switch with the operation of the UPS module(s) prevents backfeed of the External Bypass AC power into the Inverter if an incorrect switching sequence is used. A volt-free auxiliary status contact from external bypass switch QF3 is connected to UPS termi- nal X3 (MBC interface) of the parallel control board (M3).

Figure 35 External maintenance bypass cabinet with separate bypass input

400V, 50Hz 4W

Q3

4P

4P

S

400V, 50Hz 3 or 4W

Q1

UPS1

Q2

X3

CB X1

Q5

4P

Supplied by Others

400V, 50Hz 4W

Q1

UPS2

Q2

X3

CB X1

Q3

Q5

Q3

4P

Q1

UPS3

Q2

X3

CB X1

Q5

4P

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