Electrical knowledge: ac contactor basic knowledge, beginners from here to open a door

Electrical knowledge: ac Contactor basic knowledge, beginners from here to open a door

When ac contactor is selected according to load, it is usually selected only according to the rated current of load, so that the main contact of AC contactor often burns out and fuses in actual operation. The cause of this fault phenomenon is selected according to the rated current.

When ac contactor is selected according to load, it is usually selected only according to the rated current of load, so that the main contact of AC contactor often burns out and fuses in actual operation. The reason for this failure is that the method of selecting ac contactor (main contact capacity) according to the rated current is only applicable to pure resistive loads such as electric heating wire.

For the inductive load such as three-phase asynchronous motor, the starting current is about 4-7 times of the rated current due to the different starting mode, dragging load type and starting frequency. Before stable operation during startup. When selecting ac contactor for this purpose, it is also very important and necessary to consider the load starting current factor.

In order to reduce unnecessary electric shock accidents, the current ac contactor coil voltage-safety voltage level (AC36V) has become a general trend with the enhancement of safe electricity use awareness and safe operation standards. Therefore, in the design, selection and assembly of contactor, should first use the coil voltage class AC36V products. Avoid coexisting voltage levels of AC380V and AC220V coils in the line.

To reduce the number of other auxiliary devices (such as intermediate relays, etc.). And reduce the volume of electronic control system, in the selection of ac contactor, should be based on the number of auxiliary contacts required by the contactor in the line, considering the type of AC contactor. For example, when there are many auxiliary contacts in the line, it is more sensible to choose CJX series ac contactors that can hang 2 pairs or 4 auxiliary contacts than CJT series AC contactors.

Based on the above three factors, the contactor (coil) control mode does not need to be compensated. At present, PLC and other easy to centralized control of industrial control equipment application more and more widely. In this process, there will be contactor coil directly connected to the PLC output end, PLC internal output devices (relay, transistor, thyristor) damage. The reason for the failure is that the current value of the contactor coil is greater than the current-carrying capacity of the PLC output device in the drawing process. Therefore, when using programmable controllers to control contactors, relays should be used as the control transition between them.

If you have any questions about ac contactor, please contact us. We are a manufacturer of ac contactor. We have a detailed understanding of the characteristics and methods of using AC contactor. We can introduce the knowledge of ac contactor from different aspects.