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Mobile WebSiteFirst, the structure and working principle
1. Structure: It is generally composed of metal cable joint electromagnetic mechanism, contact, arc extinguishing device, release spring mechanism, bracket and base.
2. Working principle: According to the electromagnetic principle: When the electromagnetic coil is energized, the coil current generates a magnetic field, so that the static iron core generates electromagnetic attraction to attract the armature, and drives the contact action to make the normally closed contact open and the normally open contact close. The two are linked. When the coil is de-energized, the electromagnetic force disappears, and the armature is released by the action of the release spring, so that the contact is restored, that is, the normally open contact is opened, and the normally closed contact is closed.
Second, classification and characteristics
1. AC contactor: The AC contactor coil is connected to AC power, the main contact is turned on, and the AC main circuit is cut off.
2. DC contactor: The DC contactor coil is connected with DC current, the main contact is turned on, and the DC main circuit is cut off.
Third, the main technical parameters
Coil voltage, main contact rated current, main contact rated voltage, auxiliary contact rated current, number of auxiliary contacts, number of contactors, and mechanical life and electrical life of the contactor.
Fourth, the principle of choice
1. The type of contactor should be consistent with the nature of the load. The AC contactor should be used to control the AC load, and the DC contactor should be used to control the DC load.
2. The rated working voltage of the main contact should be greater than or equal to the voltage of the load circuit.
3. The rated operating current of the main contact should be greater than or equal to the current of the load circuit.
4. The working current of the contactor main contact is the current value that can work normally under the specified conditions (rated working voltage, use type, operating frequency, etc.). When the actual operating conditions are different, this current value will also follow. change.
