Industry Dynamic

About DC contactor


The DC contactor adopts a modular design, which can assemble the number of contacts required by the customer and the contact form (normally open, normally closed and conversion) required by the customer with the least number of parts; the contact breaking voltage of this series of products is high. , and uses cross-blowing magnetic field arc extinguishing, the highest breaking voltage can reach 220VDC. The product is suitable for program-controlled power supply or uninterruptible power supply system, forklift, electric vehicle, construction machinery system.

Advantages of DC contactors:

1. Reliable sealing enables the product to be used for a long time in harsh and explosion-proof environments, and its internal components such as coils and contacts are not oxidized. At the same time, the product has the advantages of low energy consumption, less heat generation, long life, small size, and light weight. .

2. Can control high voltage and high current

3. Energy saving Some specifications of products use energy-saving panels.

4. The smaller arc makes the product more effective and safer to use. The use of inert gas sealing ensures that there is basically no arc between the contacts when the product is in motion, and the arc is extinguished by magnetic blowing to ensure safety.

5. High stability The internal mechanism and structure are completely sealed in an inert gas, free from interference from external adverse factors, and the contact resistance remains stable for a long time.

6. Wide range of applications Applications include: DC power control, battery switch control, circuit safety protection, etc.

Working principle of DC contactor:

When the contactor coil is energized, the coil current generates a magnetic field, which makes the static iron core generate electromagnetic attraction to attract the moving iron core, and drives the AC contactor

Contact action: The normally closed contact is open, the normally open contact is closed, and the two are linked. When the coil is powered off, the electromagnetic attraction disappears, and the armature is released under the action of the release spring to restore the contacts: the normally open contact is disconnected, and the normally closed contact is closed


Selection method of DC contactor:

1. Select the type of DC contactor The type of DC contactor should be selected according to the type of load current and the weight of the load, that is, whether it is an AC load or a DC load, whether it is a light load, a general load or a heavy load.

2. The rated current of the main contact of the DC contactor The rated current of the main contact of the DC contactor can be calculated according to the empirical formula IN main contact ≥ PN motor/(1~1.4)UN motor In case of frequent reversing, generally reduce the rated current of the main contacts of the contactor by one level.

3. Rated voltage of the main contact The voltage marked on the nameplate of the contactor refers to the rated voltage that the main contact can withstand, not the voltage of the attracting coil. When in use, the rated voltage of the main contact of the contactor should not be less than the rated voltage of the load.

4. Selection of operating frequency The operating frequency refers to the number of times the contactor is turned on and off per hour. When the on-off current is large and the on-off frequency is too high, it will cause severe overheating of the contacts, or even welding. If the operating frequency exceeds the specified value, it should be Choose a DC contactor with a higher rated current.

5. Selection of coil rated voltage The rated voltage of the coil is not necessarily equal to the rated voltage of the main contact. When the circuit is simple and the use of electrical appliances is small, the voltage of 380V or 220V can be directly selected. If the circuit is complicated and the use of electrical appliances exceeds 5h, 24V, 48V or 110V can be used Coils with voltage (36V, 110V, or 127V in 1964 international regulations).