Precautions for Relay Selection

In order to use the relay correctly, please understand the characteristics of the selected relay, confirm whether it is consistent with the use conditions and environmental conditions of the relay, and at the same time, you must master the coil usage method, contact method and environmental conditions of the relay in actual use.

1. To choose the correct type
To make good use of the relay, it is very important to select the correct type. First, you must have a thorough understanding of the nature, characteristics and use requirements of the controlled object, and consider it carefully.
2. Understanding of the docking point
The dynamic and static contacts that are disconnected when the relay coil is not electrified are called "normally open contacts", otherwise, they are called "normally closed contacts".
3. Methods of eliminating contact sparks
Since the on-off current of the relay contacts is small, there will be no arc between the contacts, but "spark discharge" will occur. This is due to the presence of inductance in the contact circuit, and overvoltage will appear on the inductance when it is disconnected, which is different from the power supply voltage. It is added to the contact gap together, so that the contact gap just separated a little distance breaks down and discharges.
4. The method of increasing the contact load
In use, if the load capacity of the contacts cannot meet the requirements of use, the method of connecting several pairs of contacts in parallel can be used to solve the problem.
5. Solutions when the return coefficient does not meet the requirements
The so-called return coefficient kf is a parameter that reflects the degree of cooperation between the suction characteristic and the reaction force characteristic, that is, the difference between the action value and the release value of the relay.
6. Improvement of the pull-in release time that does not meet the requirements
When the pull-in and release time of the relay cannot meet the requirements of use, the time constant of the relay coil loop can be changed to solve it.