1、 Contact malfunction

1. Contact adhesionThe relay cannot be released after being pulled in, resulting in the circuit being continuously closed. Possible reasons include the presence of foreign objects between the contacts, uneven contact surfaces, or insufficient contact pressure.
2. Poor contact of contactsThe circuit state of the relay is unstable or cannot be closed correctly after being pulled in. Possible reasons include oxidation, contamination, and wear on the contact surface, leading to an increase in contact resistance.
3. Contact erosionThe melting or erosion of the contact surface affects the normal operation of the contact. Possible reasons may include long-term overload, high voltage, or contact materials that are not resistant to high temperatures.
4. Loose or cracked contactsLoose contacts may be caused by unreasonable dimensions of the mating part between the spring and the contact or improper adjustment of the riveting pressure; Contact cracking may be caused by high material hardness or excessive pressure.

2、 Coil malfunction

1. Open circuit of coilInternal wire breakage or loose wiring terminals in the coil prevent the coil from forming a closed circuit and generating sufficient electromagnetic force to engage the relay.
2. Coil short circuitThe internal insulation layer of the coil is damaged or the coils come into contact with each other, causing a short circuit in the coil, resulting in abnormal current when the relay is powered on, and even burning out the coil.
3. Coil burnt outLong term overload, high voltage, internal coil faults, or high operating frequency can cause the coil to overheat and burn out.

3、 Magnetic circuit malfunction

1. Wear of iron core or armatureCausing an increase in magnetic circuit gap and affecting the magnetic circuit state of the relay. Possible reasons include wear caused by prolonged use or mechanical vibration.
2. Excessive residual magnetismIn some DC relays, due to mechanical wear or damage to non-magnetic gaskets, the minimum air gap after the armature is closed becomes smaller, resulting in excessive residual magnetism and preventing the armature from releasing.
3. Broken magnetic ring or rusted iron coreWhen the magnetic ring on the iron core of the communication relay breaks, or when the armature and the iron core pole surface rust or invade impurities, it will cause the armature to vibrate and produce noise.

4、 Mechanical malfunction

1. Transmission mechanism stuckDust and foreign objects enter the interior of the transmission mechanism or the design of the transmission mechanism itself is unreasonable, resulting in the transmission mechanism being unable to operate smoothly.
2. Reaction spring failureLong term use can lead to spring fatigue or quality issues with the spring itself, causing the reaction spring to be unable to provide sufficient elasticity, resulting in the relay not being able to release in a timely manner when the power is cut off.

5、 Other faults

1. Glass insulator damageDuring inspection, assembly, adjustment, transportation, and cleaning, glass insulators may experience air leakage due to bent pins, falling pieces, or cracking, resulting in a decrease in insulation and voltage resistance performance.
2. Unstable parametersA considerable part of the components of electromagnetic relays are riveted together, resulting in loose rivet joints or poor bonding strength, leading to unstable relay parameters, large parameter changes at high and low temperatures, and poor resistance to mechanical vibration and impact.