UPS 120, UPS 150, UPS 250, UPS 300, UPS 301, UPS 500, UPS 600, UPS 750 and UPS 900 Uninterruptible Power Supplies Caterpillar

MMS Internal and Maintenance Bypass

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When servicing or repairing electric power generation equipment: Make sure the unit is either locked out or tagged DO NOT OPERATE. Remove all fuses. Make sure the generator engine is stopped. Make sure all batteries are disconnected. Make sure all capacitors are discharged. Make sure residual voltage in the rotor, stator and the generator is discharged. Failure to do so could result in personal injury or death.

System Internal Bypass Procedure

The system Internal bypass is used when the following is required:

The system needs to use voltage to regulate the power to the load but not protect the load in a utility outage.

1. Turn the key switch to BYPASS position at the system cabinet.

2. Turn the key switch to BYPASS position at the MMUs.

The system is now in BYPASS.

Illustration 1	g01272005

(1) LCD display

(2) Key switch

System Configurations for Maintenance Bypass

Follow the instructions in the system configuration for the proper machine.

Single Input without Switches

Refer to Systems Operation, Testing and Adjusting, RENR9988, "Single Input without Switches".

Dual Input with Two Switches

Refer to Systems Operation, Testing and Adjusting, RENR9988, "Dual Input with Two Switches".

Dual Input with Three Switches

Refer to Systems Operation, Testing and Adjusting, RENR9988, "Dual Input with Three Switches".

Single Input with Three Switches

Refer to Systems Operation, Testing and Adjusting, RENR9988, "Single Input with Three Switches".

Dual Input with NO Switches

Refer to Systems Operation, Testing and Adjusting, RENR9988, "Dual Input with No Switches".