ZW32-40.5 Pole-Mounted High Voltage Vacuum Circuit Breaker

I. Overview of ZW32-40.5 Pole-Mounted High-Voltage Vacuum Circuit Breaker

The ZW32-40.5 outdoor high-voltage vacuum circuit breaker adopts a uniquely designed integrated solid-sealed pole and a highly reliable operating mechanism. Developed and improved by Zhejiang Chuanlong Electric Co., Ltd., the ZW32-40.5 vacuum circuit breaker can replace the ZW7-40.5 vacuum circuit breaker for pole-mounted intelligent vacuum circuit breaker applications. This device is primarily used in medium-voltage overhead line grids for switching load current, overload current, and short-circuit current.

Common models: ZW32-40.5/1250-25 ZW33-40.5/1250-25

II. Structure and Working Principle of ZW32-40.5 Vacuum Circuit Breaker

The ZW32-40.5 outdoor high-voltage vacuum circuit breaker mainly consists of an integrated solid-sealed pole, current transformer, operating mechanism, and enclosure. This model features a compact design, with the enclosure made of high-quality carbon steel or stainless steel. The current transformer can be selected in the range of 30-600/5 according to user requirements. The ZW32-40.5 pole-mounted high-voltage vacuum circuit breaker is combined with a matching intelligent control unit. It allows for remote on-site switching operations and can also be operated via remote control through communication interfaces. Other information from the circuit breaker can be transmitted to the control center, with communication channels including cable, fiber optic, GPRS/CDMA, GSM, etc.

III. Working Principle of ZW32-35 Vacuum Circuit Breaker

1. Arc Extinction Principle: The ZW32-40.5 outdoor high-voltage vacuum circuit breaker uses a vacuum interrupter chamber, with vacuum serving as the arc extinguishing and insulating medium, offering extremely high vacuum levels. When the moving and fixed contacts are electrically separated by the operating mechanism, a vacuum arc is generated between the contacts. Due to the special structure of the contacts, an appropriate longitudinal magnetic field is also produced in the contact gap, which helps maintain the vacuum arc as a diffused type and distributes it evenly across the contact surface, keeping the arc voltage low. At natural current zero crossing, residual ions, electrons, and metal vapor recombine or condense on the contact surface and shield within microseconds, quickly restoring the dielectric strength of the interrupter chamber gap, thereby extinguishing the arc and achieving interruption. The use of a longitudinal magnetic field to control the vacuum arc gives the vacuum circuit breaker strong and stable current interruption capability.

2. Motor Energy Storage: The motor outputs torque to the pinion of the mechanism, which drives the large sprocket on the main shaft, rotating the crank arm and storing energy in the closing spring. When the screw on the crank arm presses the limit switch, the motor power is cut off, and spring energy storage is completed.

3. Manual Energy Storage: Rotating the output shaft of the mechanism transfers rotational torque through the pinion on the output shaft to the large gear fully engaged with the pinion, driving the crank arm to rotate and store energy in the closing spring.

4. Closing Solenoid Operation: Upon receiving a closing signal, the moving iron core of the closing solenoid moves upward, pushing the closing trip lever upward and rotating the closing half-shaft counterclockwise. This releases the constraint on the closing latch. Simultaneously, the closing latch is pressed by the roller and rotates counterclockwise, releasing the energy storage maintenance. The cam on the main shaft, due to the contracting force of the closing spring, generates an impact force that strikes the rocker arm on the manual energy storage shaft (i.e., output shaft), transmitting force through the linkage to the switch, thus completing the closing operation.

5. Manual Operation: When the fork installed on the closing half-shaft rotates counterclockwise, it drives the closing half-shaft to rotate counterclockwise, producing the same effect as the closing solenoid operation.

6. Reclosing Operation: After the mechanism releases the energy of the storage spring to complete the closing operation, it proceeds with energy storage again while in the closed state. Once energy storage is completed, the mechanism is in a closed and energized state. Upon receiving the correct signal, the mechanism can perform an automatic reclosing operation.

7. Opening Solenoid Operation: Upon receiving an opening signal, the moving iron core of the opening solenoid moves upward, pushing the opening trip lever upward and rotating the opening half-shaft counterclockwise. This releases the constraint on the opening latch. Simultaneously, the opening latch is pressed by the roller and rotates counterclockwise. The rocker arm, driven by the thrust of the internal opening spring of the switch, rotates counterclockwise, thus completing the opening operation.

8. Manual Operation: When the fork installed on the opening half-shaft rotates counterclockwise, it drives the opening half-shaft to rotate counterclockwise, producing the same effect as the opening solenoid operation.

9. Overcurrent Trip Operation: When the overcurrent coil in the overcurrent trip unit passes the specified trip current, the solenoid actuates, and the push rod pushes the trip lever. This causes the opening half-shaft to rotate counterclockwise, releasing the constraint on the opening latch and producing the same effect as the opening solenoid operation, thereby completing the overcurrent trip operation of the circuit breaker.