Regarding the bonding concept of the relay, the main solution is to melt and weld the fixed contact electrical contacts and movable silver contacts of the relay together, so that the disconnection cannot be controlled normally. There is a sticking phenomenon in which the relay is in the open state and cannot be closed normally.

Contact welding of bimetal electric contacts is divided into static welding and dynamic welding.The static welding of Bimetal Contact is that when the relay is in the closed state, due to the abnormally large current, the Joule heat generated by the Bimetal Electronic Contacts resistance melts the metal in the Bimetal Silver Contacts part of the two contacts, welds and combines without breaking; in the fixed Bimetallic Silver Contacts connection Contacts in or in closed Precision Electrical Contacts will statically weld with sufficient force.Dynamic welding of electrical contacts means that when the relay is closed or opened, the arc releases a large amount of heat in a short period of time, causing the contacts to melt or vaporize and weld.

In the case of less severe soldering, sometimes under a certain vibration, the adhered Composite Contacts will separate again, leaking traces of melting.

There are two reasons for arcing in dynamic welding:

1. When the relay is closed, the capacitive load will cause a large short-circuit current in the circuit, and the jitter of the relay will cause arcing, which will generate a lot of heat and lead to welding;

2. The Electrical Silver Contacts use relays to cut off large current loads, causing arcs and generating a lot of heat to cause welding;

There is also a special case called the electromagnetic repulsion scheme. When the relay is closed, due to the large short-circuit current, the Electrical Contact Point will bounce, causing arcing, and generating heat leading to welding, as shown below:

Because the silver contact surface is not flat; the black circles indicate that the two current paths are parallel and opposite. As these two Silver Alloy Electrical Contact Rivets are formed, the magnetic field creates a repulsive force between them, which is applied to the two Cold Headed Electrical Contacts , forcing the contacts apart.

When the current flowing through the silver contacts is large, the repulsive force is greater than the suction and holding force of the Silver Electrical Contact, the two Electronic Contacts are separated, and an arc is generated, and the released heat causes the Electrical Fixed Contacts to weld.