As a DC contactor Manufacturer, we offer one of the most comprehensive selections of DC power contactors to meet your requirement of different budget and applications. There are 3 Series of high voltage contactors in our catalogue, 12-450V DC contactors ZJQ series, 12-900V DC contactors EVQ Series, 12-1500V DC contactors EVH Series. All these electromagnetic contactors can be used in a wide range of applications where fast and reliable DC switching operations are required. Buy high quality DC contactors at factory price, you are in the right place.

We realize that your critical application could require a highly specialized contactor, our experienced technical sales team and engineers will be pleased to develop the solution optimized for your needs.

DC contactor as a key EV parts, it is used to switch power of DC loads supplied by the traction battery in an EV. It is critical both for safety and stability. Based on defective free principle, HOTSON strictly control the quality through whole process, beginning from raw material inspection, onsite sampling check during production, and 100% tested before package.

Before choose the suitable DC contactor for your application, there are some questions or knowledge about DC contactors you may want to know, we prepared some articles for you and more to coming,so enjoy read…

What is DC Contactor and How Does DC Contactor Work?

What is the difference between AC and DC contactor?

What is the difference between relay and contactor?

5 tips to choose suitable DC contactor ?

DC contactor is an electromechanical device using low voltage to remotely control the on/off switch of high voltage DC circuit; it switches on and off the current to protect against electric shock, fire, equipment damage, etc. Mostly it is designed as Normally Open (Form A), when the coil is energized it creates a magnetic that pulls in the plunger, SPST (Single pole single thread), and with optional auxiliary contact. High voltage DC contactor is the core component of new energy vehicles, usually used to switch DC power to any of the loads supplied by the traction battery in EV. It’s also widely used in charging station, energy storage, and photovoltaic and wind power system.

The features of DC contactor are small size, light weight, reliable and safe with arc extinguishing.

The Structure of DC Contactor

DC contactor consists three parts: contact system, electromagnetic system and arc extinguishing system.

The contact system is the current-carrying part of the contactor, DC contactor has the main contact and auxiliary contact, and it includes fixed/static contact, movable/dynamic contact and shaft. When fixed contact and movable contact are not contacted, the circuit is disconnected; when contacted, the circuit is connected.

Electromagnetic system, it includes coil, movable iron core, yoke iron, magnetic conductive sheet. The electromagnet (or coil) provides the driving force to close the contacts. The enclosure is a frame housing the contacts and electromagnet. Enclosures are made of insulating materials to protect and insulate the contacts and provide measures of protection against personnel touching.

Arc extinguishing system/magnetic blowout use blowout coils to lengthen and move the electric arc. When DC contactor disconnects large DC current, the arc will be difficult to be extinguished, it producing a strong arc. In order to extinguish the arc quickly, we use magnetic blowing arc-extinguishing equipment.

HOTSON has 2 types of contactors which are epoxy sealed contactor and ceramic sealed contactor; below are the pictures showing the construction of our contactors.

Sometimes an economizer circuit is also installed to reduce the power required to keep a contactor closed. Such a circuit can save substantial amount of power and allow the energized coil to stay cooler.

Auxiliary contact system

Auxiliary contact is used to detect the current state of the main contact, whether the main contact is disconnected in accordance with the control instruction, and determine whether the main contact has failed. Auxiliary contact is often used in DC contactor to connect and disconnect the control circuit and signal circuit, it’s very convenient to monitoring the working status of main contact. It includes micro switch, PCB, switch Top Rod.

Working principle: when the contacts are moved, swing rod of the micro switch is driven by swing rod, the micro switch closed; it indicates the synchronization between the main contacts and auxiliary contacts. Below are the pictures of common structure of auxiliary contacts.

We are proudly to show our patent structure of auxiliary contact below:

HOTSON high voltage DC contactor

The new energy industry is mainly based on direct current. HOTSON’s high-volatge DC contactors  are mainly developed for the new energy industry. They use epoxy or ceramic sealed structure, and the contact chamber is filled with a Nitrogen/hydrogen gas mixture. Combined with magnetic blowout, the shape can be smaller. The narrow contact gap can also ensure efficient and safe cut-off of load voltages up to 1500VDC; compact structure, low working noise, high safety, zero arc flash, and contact system sealed in reducing gas, can be used in harsh environments.

AC contactor and DC contactor can be distinguished directly by control current for low voltage contactors. The AC control is called AC contactor, DC control on-off is called DC contactor; the contacts can pass AC or DC.

For high voltage contactors, apart from control current, they must also be distinguished by contacts. When the contacts are DC, the DC divides the positive and negative poles, and the generated arc stabilizes in the same direction. The magnetic blowing process is used to quickly extinguish Arc, and the contact adopts the magnetic blowout arc extinguishing process as a DC contactor. When the contacts are AC, the AC is non-polar, the generated arc and direction are weak and self-extinguishing and unstable. The anti-arc leakage process can be an AC contactor.

1.The main differences between AC contactors and DC contactors: It’s the iron core and the coil.

The core of the AC contactor generates eddy current and hysteresis loss, while the DC contactor has no core loss. Therefore, iron core of AC contactor is usually made of silicon steel sheet insulated from each other, and it’s made into E shape. The DC contactor iron core can be a whole piece of cast steel, and most of them are U-shaped.

The number of coil turns of the AC contactor is small, and the number of coil turns of the DC contactor is large. From the volume of the coil, it can be distinguished that for the case where the main circuit current is too large (Ie> 250A), the contactor should uses double series windings coil.

The coil of the DC circuit has no inductive reactance, so the coil has many turns, large resistance, and large copper loss. Therefore, the coil itself is mainly heated. In order to make the coil good heat dissipation, the coil is usually made into a long and thin cylindrical shape.

The AC contactor coil has a small number of turns and low resistance, but the iron core generates heat. The coil is generally made into a thick and short cylindrical shape with a certain gap between it and the iron core to facilitate heat dissipation and prevent the coil from being damaged by heat. Therefore, the coil itself is mainly heated. In order to make the coil good heat dissipation, the coil is usually made into a long and thin cylindrical shape.

2.As the AC contactor passes single-phase AC power, in order to eliminate the vibration and noise generated by the electromagnet, a short-circuit ring is embedded on the surface of the static iron core, while the DC contactor is not required.

3.AC contactor adopts grid arc extinguishing device, while DC contactor adopts magnetic blowing arc extinguishing device.

4.The starting current of the AC contactor is large, and its operating frequency is up to about 600 times / hour, and the operating frequency of the DC contactor can be up to 1200 times / hour.

If the AC and DC contactors are connected incorrectly, it means that the DC power is connected to the AC contactor, the coil will immediately burn. If AC power is connected to DC contactor, the contactor cannot be closed.

The AC contactor can replace the DC contactor in emergency, and the pull-in time cannot exceed 2 hours (because the heat dissipation of the AC coil is worse than that of the DC, which is determined by their structure), it is best to use the AC coil for a long time A resistor is connected in the middle of the string, but the DC contact cannot be used instead.

Relays and contactors perform the same task of switching a circuit. Both are electromagnetic switches and operate under similar principles. The difference comes if we see from the application perspective. Contactors are used for high voltage switching purposes whereas relays are used for low voltage switching. The function of the contactor is mainly to connect and disconnect the main circuit. The main function of the relay is suitable for signal detection, conversion and transmission. Both components are very important for the design of the circuit.

The essential difference between a relay and a contactor is that they bear different loads. Contactor carry large current, while relay’s current capacity is small. In addition, the contactor is used in the main circuit and the relay is used in the control circuit. Contactor is to switch on and off large current signals and drive power equipment such as motors. Relay is to perform signal conversion.

The interface of control signals between devices of different voltage levels. The contact carrying capacity is generally small and is used to drive electrical components such as contactors.

Relays are secondary equipment, including intermediate relays, voltage relays, current relays, time relays, etc., used for signal sampling, transfer, control, protection, etc., belong to low-voltage equipment, the contact capacity is small, generally 5A.

A relay is an electrical control device. It has the interactive relationship between the control system (also called input loop) and the controlled system (also called output loop). Usually used in automated control circuits, it is actually an “automatic switch” that uses small currents to control high current operations. Therefore, it plays the role of automatic adjustment, safety protection, and conversion circuit in the circuit.

Relays are generally used in electrical control circuits to amplify the contact capacity of miniature or small relays to drive larger loads. For example, you can use the contacts of the relay to switch on or off the contactor’s coil. Generally, the relay has more opening and closing contacts. Of course, the relay can also achieve some special functions, such as logic operations, through proper connection.

When the input quantity (such as voltage, current, temperature, etc.) reaches the specified value, the relay turns on or off the controlled output circuit. Input quantity can be divided into electrical quantity (such as current, voltage, frequency, power, etc.) and non-electrical quantity (such as temperature, pressure, speed, etc.).

The contactor is used to switch on or off the load with higher power. It is used in the (power) main circuit. The main contact may have interlocking contacts to indicate the opening and closing state of the main contact.

The contactor uses the current flowing through the coil to generate a magnetic field, so that the contacts are closed, so as to reach the electrical appliance that controls the load. The contactor consists of an electromagnetic system (iron core, static iron core, electromagnetic coil) contact system (normally open contact and normally closed contact) and arc extinguishing device. The principle is that when the contactor’s electromagnetic coil is energized, a strong magnetic field will be generated, which will cause the static iron core to generate electromagnetic attraction to attract the armature and drive the contact action: normally closed contact is opened; normally open contact is closed, both are linked. When the coil is de-energized, the electromagnetic attraction force disappears, and the armature is released under the action of the release spring to restore the contacts: normally closed contacts are closed; normally open contacts are opened.

Relay function

1. Isolation function. Between the input part and the output part of the relay, there is an intermediate mechanism (drive part) that couples and isolates the input quantity, performs functional processing, and drives the output part.
2. Expand the scope of control. When the multi-contact relay control signal reaches a certain value, the multi-circuit can be switched, disconnected and connected at the same time according to different forms of the contact group.
3. Zoom in. Sensitive relays, intermediate relays, etc. can control very high power circuits with a very small amount of control.
4. Comprehensive signals. When multiple control signals are input to the multi-winding relay in a prescribed form, after a comprehensive comparison, a predetermined control effect is achieved.
5. Automatic, remote control and monitoring. The relays on the automatic device together with other electrical appliances can form a program control circuit to achieve automatic operation.

Contactor function

The function of the contactor is to use a small current to control a large current load, which can be remotely controlled, and at the same time, it can be self-locked and interlocked to prevent accidents caused by malfunction. The small current control makes the protection circuit simple and reliable.

Difference between contactor and relay

Relays: used for control circuits, low current, no arc extinguishing device, can operate under the action of electricity or non-electricity, a relay often has several pairs of normally open / normally closed nodes, which can be used for different control loops, its nodes cannot pass high current, generally not used in power circuits.

Contactor: Similar to a circuit breaker, it is used for the main circuit, has a large current, and has an arc extinguishing device. Generally, it can only operate under the action of voltage. In fact, the principle is the same, mainly because the contact capacity is different, the relay contact capacity is small, the contact can only pass a small current, which is mainly used for control, the contactor has a large capacity, and the contact can pass a large current, which is used for more main circuits.

The principle of the contactor is the same as that of the voltage relay, except that the load power controlled by the contactor is large, so the volume is also large. AC contactors are widely used as power interruption and control circuits. The relay is a small-signal control electrical appliance, which is used for motor protection or automatic control of various production machines.

The above is the difference between contactors and relays, as well as their respective structures and functions. I believe that you already have a general understanding of contactors and relays, so that when you choose, you can choose according to actual needs. HOTSON provides you with many selections of DC contactors, rating current from 10amps to 600amps, coil voltage with 12V, 24V, 48V, and rating voltage from 12V-1500V.