Auxiliary contacts, also known as auxiliary contactors are electromechanical devices used in conjunction with primary switching equipment such as contactors, circuit breakers, switches, and relays. These secondary switching devices are physically connected to the main switching equipment and work at the same time. The add-on accessories are available in a range of contact configurations and mounting styles to suit a wide range of industrial control applications.RS offer an extensive range of high-quality auxiliary contact blocks from industry-leading brands including Schneider Electric, Siemens, ABB, Lovato, Eaton, and of course RS Pro.

How do auxiliary contacts work?

Auxiliary contacts are affixed to the main contacts and change state when the main contacts do. They pass the data from the circuit to a logic controller, which in turn gives instructions to the linked devices about whether to turn on or off. Alternatively, they can be used as a standalone hardware control unit. Auxiliary contacts are available in a variety of mounting styles such as a front mount or DIN rail mount and a range of terminal types including screw terminals, screw clamp terminals, and cage clamp terminals making it easy to find the right contact for the application.

What are auxiliary contacts used for?

One common usage of auxiliary contacts is in push-button controllers, where they can be built into the start button. They are a common component in relay logic circuits solid-state electronics, electric motors, motor control schemes, and other industrial control applications.

What are the different types of contact blocks?

There are two types of contact, contacts that are closed in a non-activated state and those that are open. They will be described as N/C (normally closed) and N/O (normally open).NC contacts are used as interlocks. NO contacts are used for switching on other components such as status indication lamps.