Overcurrent and Overvoltage Protection of Relays
Relays are widely used in the consumer electronics industry and industrial equipment. They have control systems (also known as input circuits) and controlled systems (also known as output circuits). They are actually an "automatic switch" that uses small currents to control large currents. Therefore, they play a role in automatic regulation, safety protection, and circuit conversion in circuits.
Relays may be damaged due to overcurrent or overvoltage, and consist of one or several pairs of contacts and windings. When current flows through the winding, the contacts will open or close.
When the relay interrupts the current flowing to the inductive load, voltage spikes occur, which is a common problem. In severe cases, voltage spikes can exceed the rated voltage of the relay contacts, causing damage to the contacts. It may be suddenly damaged and severe, or very slowly, and will only manifest after many years.
In addition, when the contacts are disconnected and the current is interrupted, excessive current flowing through the relay contacts can also cause damage. Excessive current and voltage can also damage the winding of the relay.
If the relay winding is designed to only have current flow for a short period of time during normal operation, if there is external current flowing for a long time, although the current is within the normal operating range, it will eventually burn out the winding.
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