1. classification of AC contactor

There are many types of AC contactors, and their classification methods are different. According to the general classification method, there are probably the following categories.

① According to the number of main contacts, it can be divided into single pole, bipolar, three pole, four pole and five pole AC contactor. Single pole AC contactor is used for single-phase electric load, such as lighting load, Hummer, etc., which can be selected in motor energy consumption braking system; bipolar AC contactor is used in motor rotor control circuit of winding wire type three-phase asynchronous motor, which is used for connection starting winding resistance during startup; three pole AC contactor is used for three-phase load, such as motor operation and other places, and it is more common to apply The four pole AC contactor is used for the lighting lamp route of three-phase four wire system, and can also be used to control the load of the double circuit power supply motor; the five pole AC contactor is used to form the self coupling compensation starter or operate the double cage motor to change the winding resistance wiring method.

② According to the arc extinguishing material, it can be divided into gas type AC contactor, vacuum pump type AC contactor, etc. The AC contactor with gas insulation layer is used for general load, and the AC contactor with vacuum pump insulation layer is commonly used in some special places such as medium ore, crude oil, chemical plant and voltage of 660V and 1140V.

③ According to whether there is contact, it can be divided into contact AC contactor and contactless AC contactor. The common AC contactors are mostly contactless AC contactors, but contactless AC contactors belong to the materials used in electronic information technology. Thyristor is generally used as the guiding element of control circuit. Because the opening voltage required for thyristor on and off is not large and there is no fire when the control circuit is on, it can be used for high actual operating frequency of machine equipment and inflammable, inflammable and explosive places without noise.

2. main parameters of AC contactor

(1) Rated voltage refers to the voltage in the operation of the rated value of the main contact, which shall be equivalent to the rated voltage of the load. A contactor often requires a number of rated voltages, and lists the relative rated voltage or operating output power. Generally, the voltage in larger operation is rated voltage. The common rated voltage values are 380V, 220V, 660V, etc.

(2) The current of the contact of the AC contactor with rated voltage under the standard in rated value operation. In the control circuit of three-phase motor of 220V, the electric flow rate in rated operation can be similar to twice the operating output power. The common rated voltage levels are 5a, 10a, 20a, 40a, 60A, 100A, 150A, 250A, 400A and 600A.

(3) The ability of conduction can be divided into larger access current and larger on and off flow. The larger current input is the larger current which is not easy to cause arc welding when the contact is closed; the larger open and power off flow is the larger current amount to be cut off by spectrum when the contact is broken. The general on working capacity is 5-10 times of rated voltage. Naturally, this value is related to the voltage level of the off-off power circuit. The higher the voltage, the less the on-going ability.

(4) The position value can be divided into the suction voltage and the release voltage. The suction voltage refers to the minimum voltage when the AC contactor can be absorbed before it is pulled in, slowly raising the voltage on both sides of the suction coil. The released voltage refers to the slow reduction of the voltage of the suction coil after the AC contactor is pulled in, and the larger voltage when the AC contactor is released. Generally, the suction voltage shall not be less than 85% of the rated voltage of the coil, and the released voltage shall not be higher than 70% of the rated voltage of the coil

(5) When the rated voltage of the coil is attracted, the voltage applied on the coil is attracted when all the normal operation of the AC contactor is in operation. Generally, the voltage value, coil turns of coil, cable diameter and other data information are marked on the wire package, rather than on the factory nameplate of AC contactor casing. Attention should be paid to in many aspects when applying.

(6) The actual operating frequency AC contactor in the moment of absorption, the current consumption of the coil to attract is 5-7 times larger than the rated voltage. If the actual operating frequency is too high, the coil will be more serious hot, and immediately endanger all normal application of the AC contactor. Therefore, the allowable practical operation frequency of AC contactor is required, which is generally the highest allowable operating frequency per hour.

(7)The service life includes the service life of electric and mechanical equipment. At present, the service life of the mechanical equipment of AC contactor has reached more than 100 times, and the service life of electrical equipment is about 5% - 20% of the service life of mechanical equipment.