Working Principle and Commissioning Technology of ZW32-12 Spring Operating Mechanism

ZW32-12 vacuum circuit breakers use a compact CTB spring operating mechanism with direct transmission, fewer components and high reliability. The mechanism is housed in a sealed enclosure, effectively solving the rust problem.

I. Mechanism Features

• Compact design, small volume
• Dual-spring system: closing spring provides closing energy, opening spring automatically charges during closing
• Direct transmission, short path with high reliability
• Fully sealed protection against rain and dust
• Compatible with manual and electric operation, supports remote control

II. Manual Mechanism Operating Principle

Closing Operation

Pull the charging handle to charge, torque increases from small to large. When the closing spring passes the midpoint, it instantaneously releases energy, driving the crank arm and transmission shaft to close the circuit breaker. The opening crank arm engages with the opening half-shaft to maintain the closed state. The cam disengages from the rotating shaft sleeve, preventing re-closing.

Opening Operation

Pull the opening handle or when the overcurrent coil is activated, the opening half-shaft rotates, the opening crank arm disengages, and the opening spring drives the circuit breaker to open.

III. Electric Mechanism Operating Principle

Charging

After power is applied, the motor drives the cam to rotate through gears, and the closing spring is gradually elongated. After the spring passes the midpoint, the cam is held by the positioning piece, and the circuit breaker is in the ready-to-close state.

Closing

Apply voltage to the closing coil, the closing half-shaft rotates to release, and the closing spring releases energy to close the circuit breaker while the opening spring is compressed to store energy.

Opening

Apply voltage to the opening coil or when the overcurrent coil is activated, the opening half-shaft rotates to release, and the opening spring drives the contacts to separate.

Automatic Reclosing

Re-charging in the closed state elongates the closing spring, and the interlock device prevents inadvertent closing. Can achieve open-0.3s-close-open once automatic reclosing, suitable for self-healing of transient faults on overhead lines.

IV. Commissioning Points

• Check whether the charging indicator displays correctly
• Confirm that the opening/closing indication is consistent with the contact position
• Auxiliary switch contact switching timing is correct
• Secondary closing in the closed state should be prevented by the interlock
• Overcurrent coil is short-time duty, cannot be energized continuously for a long time