Auxiliary Contacts

Contacts are the conductive pieces of material that form part of an electrically controlled switch. Auxiliary contacts form part of a contactor, which is a type of switch that can be controlled remotely.

Contactors are often used in very high-power circuits, and auxiliary contacts are the last phase of contact, used to reduce the power of the current. They have a lower current rating than regular power contacts, and can be used to de-energise the contactor.

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.

What are auxiliary contacts used for?

One common usage of auxiliary contacts is in push button controllers, where they can be built in to the start button.