What are the most common problems with relays

Update:06-08-2021
Relay (English name: relay) is an electrical control device, which is an electrical appliance that causes the controlled quantity to undergo a predetermined step change in the electrical output circuit when the input quantity (excitation quantity) changes to the specified requirements. It has an interactive relationship between the control system (also called the input loop) and the controlled single-phase relay system (also called the output loop). Usually used in automated control circuits, it is actually an "automatic switch" that uses a small current to control the operation of a large current. Therefore, it plays the role of automatic adjustment, safety protection, and conversion circuit in the circuit.
1. The relay is not disconnected.
1) The load current is greater than the rated switching current of the SSR, which will permanently short-circuit the relay. At this time, an SSR with a larger rated current should be used.
2) Under the ambient temperature where the relay is located, poor heat dissipation for the current it bears will damage the output semiconductor devices. At this time, a larger or more effective heat sink should be used.
3) The line voltage transient causes the output of the SSR to pass through. At this time, an SSR with a higher rated voltage should be used or an additional transient protection circuit should be provided.
4) The line voltage used is higher than the rated voltage of the SSR.
5) The relay parameters are unstable.
6) Coil failure