How to eliminate sparks generated when the Cheap 5 pin relay 24v contact is activated

When testing the Cheap 5 pin relay 24v, many customers found that sparks would be generated when the contacts acted. They thought that the relay was not suitable. In fact, the jump of the relay contacts or the moment of opening and closing will cause changes in the inductive load and produce gas. Discharge phenomenon, but the current of the relay contacts is small, and there will be no arc between the contacts, but “spark discharge” will occur. This is a normal phenomenon. This is due to the presence of inductance in the contact circuit. Overvoltage will appear on the inductance when it is switched on. It is added to the contact gap together with the power supply voltage, causing the contact gap that has just been separated a little distance to break down and discharge. Due to energy limitation, only spark discharge occurs. The alternating conversion between the capacitance and the energy in the inductance between the contacts makes the spark discharge appear invisible and become a high-frequency signal, which is transmitted and distributed through high-frequency radiation and wires. Capacitors and other channels crosstalk into related circuits, causing interference signals. In addition, spark discharge will damage the contacts and reduce the service life of the contacts. Electric sparks will ablate the surface of the contacts, causing them to be uneven and cause poor contact failures.

Therefore, in addition to considering whether the Cheap 5 pin relay 24v specification is not suitable, the most important thing is to find a way to eliminate sparks. How to eliminate sparks?

The practical spark extinguishing circuit is the RC spark extinguishing circuit. The basic principle of the RC spark suppression circuit is to connect the R and C phases in series and then connect them in parallel at both ends of the relay contacts. The energy in the inductance does not pass through the contact but passes through the RC; it only absorbs the self-induced potential when the contact is disconnected. At the moment the Cheap 5 pin relay 24v contact is turned on, because RC is short-circuited, there is no absorption. Outside the dotted line is a fully absorbing circuit. When the contact is disconnected, the self-induced potential is consumed on the load rL through the pole tube. . Just choose one of the above circuits in practical applications. But it should be noted that the RC parameters should be selected appropriately. The parameters are mainly determined by experiments. Usually the capacitor C can be selected according to the load current 1A/1μF. When using a diode, its positive and negative polarity should be connected correctly, and the voltage of the diode V should be sufficient. It should be pointed out that the RC spark extinguishing circuit should be installed close to the relay contacts, and the connection line should be as short as possible to ensure the effect of the spark extinguishing circuit.

After adding the spark suppression circuit, it not only makes the circuit safer and has no sparks, but also greatly extends the service life of the Cheap 5 pin relay 24v and reduces the maintenance intensity. It is a very practical method to eliminate the spark of the relay. Have you learned?