Vacuum circuit breaker with Electromagnetic Operating Mechanism

The ZW7-40.5 series outdoor high voltage power station vacuum circuit breaker, available in both sectionalized and center-mounted designs, is a three-phase AC 50Hz outdoor high voltage switch device. It is specifically designed for control and protection in 35kV transmission systems and can also be used in applications such as contactors and capacitor bank switching.

This vacuum circuit breaker is primarily used for control and protection in outdoor 35kV power transmission and transformation systems. It is also suitable for normal operation and short-circuit protection in urban and rural distribution networks and industrial and mining enterprises. The overall structure is a porcelain bottle pillar type, with a vacuum arc extinguishing system housed in the upper porcelain bottle and a pillar porcelain bottle at the bottom. It is specifically suitable for frequent operation environments. Moreover, it offers excellent sealing properties, resistance to aging and high voltage, non-combustibility, non-explosiveness, long service life, and easy installation and maintenance.

Overview:

The ZW7-40.5 outdoor high voltage vacuum circuit breaker features a unique design with sectionalized poles and a highly reliable operating mechanism. It is extensively used in medium voltage overhead line networks for load breaking and making, overload current, and short-circuit current operations.

Key Features:Highly reliable performance throughout its lifespanCompletely maintenance-freeHigh mechanical and electrical enduranceCompact design with small size and light weight, facilitating installationOperating Conditions:Ambient temperature: not exceeding +40°C, not lower than -15°CAltitude: not exceeding 2000mWind speed: not exceeding 34m/sNegligible vibration or ground motion from switchgear and control equipmentPollution level: Level IVStorage temperature: -40°C to +85°CStructure:

The ZW7-40.5 outdoor high voltage vacuum circuit breaker consists of integrated poles, current transformers, operating mechanisms, and a steel enclosure. It features a compact design, with the high-quality steel enclosure ensuring durability. The current transformers can be selected according to user requirements.

Additionally, the ZW7-40.5 vacuum circuit breaker is compatible with an intelligent control system. It can be operated locally for opening and closing switches, as well as remotely controlled through communication interfaces. The breaker's information can also be transmitted to a control center using various communication channels such as cables, optical fibers, GPRS/CDMA, or GSM.

Working Principle:

Arc Extinction: The ZW7-40.5 outdoor high voltage vacuum circuit breaker employs a vacuum arc extinguishing chamber with high vacuum insulation properties. When the movable and fixed contacts separate under the action of the operating mechanism, a vacuum arc is generated between the contacts. The contact's special structure creates an appropriate longitudinal magnetic field within the contact gap, enabling the vacuum arc to diffuse and burn uniformly on the contact surface, maintaining a low arc voltage. When the current naturally crosses zero, the remaining ions, electrons, and metal vapors quickly recombine or condense on the contact surface and shield, restoring the insulation strength of the arc extinction gap. As a result, the arc is extinguished, achieving electrical isolation. The adoption of the longitudinal magnetic field control enables the vacuum circuit breaker to possess strong and stable breaking current capabilities.

Electromechanical Energy Storage: The electric motor applies torque to the small gear on the mechanism, transmitting it to the large chain wheel on the main shaft, which in turn drives the moving arm to rotate, thus accumulating energy in the closing spring. When the screw on the moving arm depresses the travel switch, the power supply to the electric motor is cut off, and the energy storage is completed.

Manual Energy Storage: Rotating the output shaft of the mechanism transfers the rotation torque to the large gear on the output shaft, which fully engages with the small gear. This drives the moving arm to rotate, storing energy in the closing spring.

Closing Electromagnet Operation: Upon receiving the closing signal, the dynamic iron core of the closing electromagnet moves upward, pushing the closing trip rod to move upward. This causes the closing half-axis to rotate counterclockwise. It releases the constraint on the closing latch, allowing the closing latch to rotate counterclockwise under the pressure of the roller. This disengages the energy storage mechanism. The cam on the main shaft produces an impact force due to the contraction force of the closing spring, colliding with the rocker arm on the manual energy storage shaft (the output shaft), thus completing the closing operation.

Manual Operation: When the fork installed on the closing half-axis rotates counterclockwise, it drives the closing half-axis to rotate counterclockwise, achieving the same effect as the closing electromagnet operation.

Reclosing Operation: After the energy storage spring's energy is released, the closing operation is completed. In the closed position, the mechanism performs energy storage again. After the energy storage is completed, the mechanism remains in the energized closed position. Once the correct signal is received, the mechanism can perform automatic reclosing.

Opening Electromagnet Operation: After receiving the opening signal, the dynamic iron core of the opening electromagnet moves upward, pushing the opening trip rod to move upward. This causes the opening half-axis to rotate counterclockwise, releasing the constraint on the opening latch. Simultaneously, the opening latch rotates counterclockwise under the pressure of the roller. The rocker arm rotates counterclockwise due to the push force from the internal opening spring inside the switch, thus completing the opening operation.

Manual Operation: When the fork installed on the opening half-axis rotates counterclockwise, it drives the opening half-axis to rotate counterclockwise, achieving the same effect as the opening electromagnet operation.

Overcurrent Trip Operation: When the overcurrent coil in the overcurrent trip device reaches the specified tripping current, the electromagnetic coil actuates, and the tripping rod is pushed upward, causing the opening half-axis to rotate counterclockwise and releasing the constraint on the opening latch. This achieves the same effect as the opening electromagnet operation, completing the circuit breaker's overcurrent trip operation.

In conclusion, the ZW7-40.5 medium voltage vacuum circuit breaker is a reliable and efficient solution for control and protection in outdoor high voltage power systems. With its innovative design, it ensures stable and durable performance in various applications. The vacuum arc extinguishing principle, combined with electromechanical energy storage and precise operating mechanisms, enables smooth and safe switching operations. Its compatibility with intelligent control systems further enhances its functionality and convenience. The ZW7-40.5 vacuum circuit breaker is the ideal choice for high voltage power distribution and protection requirements.