UPS 250, UPS 300, UPS 500, UPS 600, UPS 750 and UPS 900 Uninterruptible Power Supply Caterpillar

Flywheel Armature Fuses

Removal Procedure

Illustration 1	g00842981
Flywheel Armature Fuses

1. Place the system in bypass mode by turning the keyswitch to the Bypass position.

2. Isolate the system from the load by closing the bypass circuit breakers.

3. Open the circuit breaker for the output of the system.

4. Open the AC circuit breaker for the input of the system.

5. Allow the capacitor banks to bleed down for approximately 5 minutes.

   Note: When the flywheel is spinning, the following components are energized: the bus, the armature leads and the fuses. Accomplish the procedure as quickly as possible. During the procedure, the rotor is spinning on the bottom bearing.

6. Label all of the wires.

Installation Procedure

Illustration 2	g00842981
Flywheel Armature Fuses

1. Torque the nut to 22 N·m (16 lb ft).

Input Line Fuses

Removal Procedure

Illustration 3	g00842992
Input Line Fuses

1. Place the system in bypass mode by turning the keyswitch to the Bypass position.

2. Isolate the system from the load by closing the bypass circuit breakers.

3. Open the circuit breaker for the output of the system.

4. Open the AC circuit breaker for the input of the system.

5. Allow the capacitor banks to bleed down for approximately 5 minutes.

   Note: When the flywheel is spinning, the following components are energized: the bus, the armature leads and the fuses. Accomplish the procedure as quickly as possible. During the procedure, the rotor is spinning on the bottom bearing.

6. Label all of the wires.

Installation Procedure

Illustration 4	g00842992
Input Line Fuses

1. Torque the nut to 30 N·m (22 lb ft).