5 tips to choose suitable DC contactor?

It may encounter various environmental conditions or unexpected accidents during the application of DC contactor. Therefore, it’s necessary to understand the performance and working conditions of DC contactor, or even test it under actual conditions to choose the suitable contactor for your application. There are 5 aspects we suggest to consider before selecting the right product.


Regarding polarity of coil, nominal voltage, operating voltage (current), releasing voltage (current), working voltage and coil resistance, we need to consider below points:

  1. Consider the waveform of the control coil power
  2. Consider supply voltage fluctuations and power
  3. Full consideration of ambient temperature, coil temperature rise and hot start
  4. When driving a contactor with a semiconductor, consider the voltage drop

Pay attention to the voltage drop of the power supply during startup

DC contactor graphic with PWM

2.Main contacts

Consider main contacts’ rated control capacity, contact resistance, electrical life.

  1. Fully consider the contact load size, type, polarity, inrush current, switching frequency, etc.
  2. Consider the position and connection of contactor in the circuit
  3. Whether the electrical life of contactor is balanced with the life of the equipment it uses
  4. Consider the ambient temperature in actual use

Please confirm under actual use conditions (actual circuit, actual load, etc.)

DC contactor graphic2

3.Operate time

Operate time (close), bounce time (open), release time (open)

Consider the effect of actual temperature and coil voltage on operating, release and bounce time

DC contactor graphic3

4.Mechanical characters

There are 4 aspects to consider as: Vibration resistance, shock resistance, environment and mechanical life.

  1. Consider vibration and shock characteristics during use
  2. Fully consider the effects of altitude, temperature, etc. on the performance of the contactor in actual use
  3. Consider whether there is sulfur gas, oil contamination, silicon-based substances, etc. in the environment
  4. Consider the interference of the magnetic field in the environment where the contactor is used

DC contactor graphic4

5.Other characters

Besides above mentioned conditions, we also need to notice the insulation resistance, dielectric strength, installation, connection and size of contactor.

  1. Installation torque of main contact and mounting base should be within specified range.
  2. Pay attention to the flatness and smoothness of the mounting contact surface
  3. Anti-loose measures should be considered in installation.

DC contactor graphic5

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…

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