Electricity Type:AC Number of Pole:3 Phase:3 Frequency:50Hz/60Hz Number of poles:3
The vacuum contactor uses a vacuum arc extinguishing chamber to extinguish the arc to frequently switch on and off the normal operating current. It is usually used to switch on and off the 6kV, 380V (660V, 1140V) AC motors that are frequently started and stopped at medium and low voltages at long distances.
The vacuum contactor has strong arc extinguishing capability, good pressure resistance, high operating frequency, long life, no external arc spray, small size, light weight and long maintenance period.
The vacuum arc extinguishing chamber of the vacuum contactor is manufactured with high technological requirements. If the process is not good, the vacuum of the arc extinguishing chamber is likely to drop. The material of the contact material is not good, and the phenomenon of “interrupting overvoltage” will occur when the current is interrupted. That is, when the current is interrupted, the arc extinguishing capacity of the vacuum arc extinguishing chamber is very strong. A certain value of the current suddenly drops to zero, resulting in a high overvoltage. The cut-off voltage will endanger the safe operation of electrical equipment.
The vacuum contactor is mainly composed of a vacuum interrupter and an operating mechanism. The vacuum arc extinguishing chamber has two functions of reliable arc extinguishing through normal working current and frequent cutting off of working current. However, overload current and short circuit current cannot be cut off. The operating mechanism is composed of a holding coil with an iron core and an armature. The coil is energized to attract the armature and the contactor is closed; the coil is de-energized and the contactor is opened. The holding coil generally has two forms of DC and AC.
The outer shell of the vacuum arc extinguishing chamber is made of glass or ceramic insulating material, and the internal vacuum is usually above 0.01Pa. Because there is less air in the shell, the distance between the contacts can be made very small, and the arc can be easily extinguished. Contact materials are generally made of copper, antimony, osmium and other alloys. The role of the shield in the arc extinguishing chamber is that when the current is interrupted, the metal vapor that diffuses out of the condensation contact gap helps to extinguish the arc, and it can also prevent the metal vapor from splashing onto the insulating shell to reduce its insulation strength. The moving contact is connected with the lower end of the shell by a bellows, the moving contact can move up and down without air leakage.
Vacuum contactors are usually composed of insulated frame, metal base, transmission boom, electromagnetic system, auxiliary switch and vacuum switch tube. When the electromagnetic coil passes the control voltage, the armature drives the arm to rotate, so that the main contact in the vacuum switch tube is connected. After the electromagnetic coil is powered off, the main contact is broken due to the action of the opening spring.
The vacuum switch tube is composed of the upper cover, the lower cover, the metal bellows and the ceramic tube. The vacuum switch tube and the shell are made of 95 porcelain insulating materials. The corrugated ceramic tube has a large creepage distance and high mechanical strength. , Heat resistance and impact resistance. A pair of dynamic and static contacts are encapsulated in the vacuum switch tube. The contact material is wear-resistant and low cut-off value Cu-W-Wc, so that under the condition of meeting the breaking performance, the overvoltage caused by the cut-off during the breaking process is reduced. The service life of the vacuum switch tube is improved. When the metal bellows moves axially, it drives the contact to do the closing and closing action.
The electromagnetic system considers the good coordination of the actual suction characteristics and the reaction force characteristics, as well as the advantages of low noise and power saving during the operation of the contactor. The stagnation double coil is composed of two windings for starting and maintaining, and is switched by an auxiliary switch to facilitate user communication. Power supply operation, contactor with bridge rectifier.
Mechanical lock: when the closed coil is energized, the contactor is closed, and the mechanical lock is locked: when the trip coil is energized, the mechanical lock is tripped, the contactor is released, and when the trip coil is in a hot state, its voltage is at Us85 The contactor can be released reliably within the range of% -110%.
Vacuum AC contactors are widely used in coal mines, electric power, metallurgy, textiles. Various industries such as high-rise buildings.