The vacuum contactor uses the vacuum interrupter to turn on and off the normal working current frequently, and has a wide range of applications in the motor. The first thing users need to know when using vacuum contactors is the principle of vacuum contactors, which is of great benefit to users.

Working principle

The vacuum contactor is usually composed of an insulating frame, a metal base, a transmission arm, an electromagnetic system, an auxiliary switch and a vacuum switch tube. When the electromagnetic coil passes through the control voltage, the armature drives the lever arm to rotate, so that the main contact in the vacuum switch tube is connected, and the main contact is broken due to the action of the opening spring after the electromagnetic coil is powered off.

The vacuum switch tube is composed of the above cover, the lower cover, the metal bellows and the ceramic tube, etc. The vacuum switch tube, the shell is made of 95 porcelain insulating material made of corrugated porcelain tube, which has the characteristics of large creepage distance, high mechanical strength, heat resistance and impact resistance. The vacuum switch tube is packed with a pair of static and static contacts, and the contact material is made of wear-resistant Cu-W-Wc with low cut-off value, so that the overvoltage caused by cut-off during the breaking process can be reduced under the condition of meeting the breaking performance, and the service life of the vacuum switch tube can be improved. When the metal bellows move axially, the moving contacts are driven to make the opening and closing action.

The electromagnetic system considers the good match of the actual suction characteristics and reaction characteristics, as well as the advantages of low noise and power saving when the contactor is running, the retention double coil is composed of two starting and maintaining windings, and is switched by an auxiliary switch. In order to facilitate the user to operate AC power, the contactor has a bridge rectifier device.

Mechanical lock: When the closing coil is energized, the contactor is drawn, and the mechanical lock is locked: when the tripping coil is energized, the mechanical lock is released, and the tripping coil is released. When the tripping coil is in a hot state, its voltage is in the range of Us85%-110% to make the contactor release reliably.