AS9120B, ISO 9001:2015, and FAA AC 0056B ACCREDITED

How Relays and Circuit Breakers Differ From One Another

Circuit breakers are another common circuit element that can be understood as a different form of switch, able to break contacts under certain conditions for the protection of a circuit. While relays and circuit breakers share the fact that they are switches capable of managing circuits, it is important that one does not conflate the two as they perform very different roles. As such, we will briefly discuss relays and circuit breakers in this blog, allowing you to have a better understanding of the various types of switches available on the market.

When discussing relays in particular, it is important to understand them as a form of sensing and controlling device that is electrically operated. Switches will generally feature a set number of input terminals and a set of operating contact terminals, as well as contacts in multiple contact forms. The most simplistic of relays will consist of a wire coiled around a soft iron core, a low reluctance path for magnetic flux, an adjustable iron armature, and one or more contact sets. As electric current is induced through the coil, a magnetic field will be generated. This field will then move the armature to either make or break connections by adjusting contact positions.

There are many types of relays available, each varying in their specific design and capabilities. Nevertheless, many perform the same roles regardless of whether they are electromechanical, solid-state, etc. Generally, relays are implemented in a system when it is necessary for a low power circuit to control a high power or voltage circuit, or when multiple circuits are to be controlled. Additionally, they may also be relied on for isolating a low voltage circuit from a high voltage circuit.

With a circuit breaker, circuits, electrical components, appliances, and systems alike may be protected from damage that results from an overcurrent or short circuit. To do this, they feature parts that allow for a fault condition to first be detected before breaking the connection of contacts through the use of a spring, compressed air, or other forms of stored energy that is contained within the breaker. The process of separating contacts is referred to as “tripping,” and once the fault is resolved, the contacts may be automatically or manually reconnected. Similar to relays, circuit breakers may be procured in a number of types, the choice generally coming down to how much protection a particular application needs, among other factors.

With a general understanding of both types of equipment, you can see how despite sharing similar characteristics, relays and circuit breakers are quite different. As such, there is no instance generally where a relay and a circuit may be interchangeable with one another, and operations would most likely not be possible if the wrong type of equipment is used. If you are in need of a circuit breaker or relay components, let the experts at Aviation Domain 360 help you source all you need with competitive pricing and rapid lead times.

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