Customer Reported Issue: The customer reported that the breaker does not close, and the closing spring is not charging.

1. Truck Mechanism Ass'y: TEST position

2. VCB: OPEN / Charged (control power supplied)

The breaker does not close electrically (remote close) using the switch lever on the switchgear panel, even though control power is available.

When the breaker is OPEN with the spring CHARGED, the A3–A4 circuit should be closed (refer to the electrical diagram). The continuity and voltage tests using a multimeter are required to check this condition.

1. VCB Internal Circuit (A3-A4) - Wire Ass'y (Yellow) with AMP male pin connectors (A, B, and C)

Includes coils, auxiliary switches, anti-pump relay, and one-pulse controller

Critical circuit to verify component condition (continuity, no short circuits)

2. Harness wire - Truck Mechanism Ass'y

(Item Code: 76673173801 - WIRE ASS'Y,10A10B,MALE,3P,38kV,UVH)

Check continuity across connector pins and verify no open or short circuits.

3. Harness wire - PT Drawer

(Item Code: 76673173802 - WIRE ASS'Y,10A10B,FEMALE,3P,38kV,UVCH)

Check continuity across connector pins and verify no open or short circuits

The female AMP connector on Harness Wire #2 failed the voltage test, indicating that no voltage is present in the circuit.

 

Root Cause

The auto-connector (Auto-Con), which connects the VCB to the Truck Ass’y and Cradle, was not fully seated in the TEST position.

Return the Auto-Con to its initial position when the truck is in the TEST position.

At sites without a lifter, the following method was applied:

1. Move the truck assembly to the DISCONNECTED position

2. Use a hook-type tool (e.g., a crowbar with a hook tip) to fully pull out the Auto-Con and ensure it is properly seated in its initial position

3. Rack the breaker fully into the SERVICE position

4. Repeat the full rack-in / rack-out cycle three times

Result After Correction

The spring charging motor operated normally. The breaker closed and opened remotely (electrically). All functions have been restored and are operating normally.