American Power Conversion 120-160kW manual Isolating one UPS in a Parallel/Redundant System

Stop/Start UPS and Operating the External Service Bypass

2.7Isolating one UPS in a Parallel Configuration for Service/Maintenance

2.7.1 Isolating one UPS in a Parallel/Redundant System

Mains Load

Service bypass switch

APC Silcon

UPS

APC Silcon

UPS

In a redundant system one UPS may be isolated for service/maintenance without affecting other parallel UPS(s).

Action

1.Check that the remaining UPS(s) will be able to carry the load when one UPS is isolated.

2.Switch off the system to be isolated for maintenence by pushing the green ON and the red OFF button simultaneously.

3.Disconnect output and mains by setting output switches (Q002) to position 0 and input switch (Q001) to position 0. Disconnect battery by opening battery breaker.

2.7.2Switching Back the UPS to Normal Rarallel/Redundant Operation

Action

1.Set the input switch (Q001) and the output switch (Q002) to position 1.

2.Charge capacitors, connect battery, and start up the UPS as described in 2.4.1. Start UPS (from complete power down).

The UPS will automatically switch to normal operation and start load-sharing with the other parallelled UPS(s).

WARNING!

The system will discharge built-in capacitors.

ALWAYS check with a multimeter that the terminals contain no dangerous voltage before touching the system!

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User Guide APC Silcon 120-160kW 400V UPS	17