Contactors are mainly composed of electromagnetic systems, contact systems, arc-out systems and other parts.
(1) Electromagnetic system: electromagnetic system includes electromagnetic coil and iron core, is an important part of the contactor, relying on it to drive the contact closure and opening.
(2) Contact system: The contact is the executive part of the contactor, including the main contact and auxiliary contact. The main contact is on.
(3) Break the main circuit and control the large current, while the auxiliary contact is in the control circuit to meet the requirements of various control modes.
(4) Arc-killing system: arc-extinguishing device is used to ensure that the contact disconnect circuit, the resulting arc can be reliably extinguished, reducing the damage of arc to contacts. In order to quickly extinguish the arc when disconnecting, usually contactors are equipped with an arc-out device, generally using a semi-sealed vertical clay-out arc hood, and equipped with a strong magnetic blowing arc circuit.
(5) Other parts: insulated housing, springs, short-circuit rings, transmission mechanisms, etc.
Working principle: When the coil is energized, the static iron heart produces electromagnetic suction force, will be the dynamic iron heart suction, because the contact system is linked with the dynamic iron heart, so the dynamic iron heart to drive three touch pieces at the same time, contact closed, so connected to the power supply. When the coil is off, the suction force disappears, and the dynamic iron-core linkage part relies on the spring's reaction force to separate, so that the main contact is disconnected and the power supply is cut off.