AC contactors have three important sections - main contacts, auxiliary contacts and coil contact. What is an auxiliary contact? Auxiliary contact does not carry much current and gets activated and deactivated along with the main contact. It is assembled mechanically with the main contact. Auxiliary contact provides interlock connections for multiple purposes in a single circuit, which includes safety interlock, electrical interlock, etc.
Working of Auxiliary Contacts
According to the mounting position, most auxiliary contacts are either side-mounted or front-mounted. It passes the data from the main circuit to a logical controller, which further instructs the linked device about switching on or off. Let us try to understand the working of auxiliary contactors with a simple example.
Auxiliary Contactor Wiring
Consider that you need to provide the green signal indicator (strobe warning light) to check the running status of 3 phase motor having a 380V delta connection with the help 4-pole AC Contactor (3-phase NO terminals and one NO auxiliary contact). All the component wiring is done as shown in the above diagram. Now, the green push button (NO type) is pushed to energize the coil, which converts the NO contact terminals of the 4-pole AC contactor into NC to power the 3-phase induction motor. It also glows up the strobe warning light using the auxiliary contact and a set of push-up start and stops buttons.
Why to Use an Auxiliary Contact in AC Contactor?
Auxiliary contacts control the circuit for multiple operations. It protects the circuit breaker and equipment from damage by blowing its fuse without affecting the main circuit breaker.
Auxiliary contacts in contactor act as a current relief remedy for the overload circuit. Without such aux-contacts, the main-circuit breakers work harder to handle the extra current needed by under-capacity circuits, which will fail the main circuit breakers.
It saves the circuit to get failure, shocks, and fire hazards due to overheating of the components. Auxiliary contacts minimize the risk and make a secure environment for to use of high-power electricity.
Peaco Support supplies a variety of AC contactors with optional auxiliary add-on blocks on the side or in the front mount position. Combining the auxiliary contact block with the CJX2 contactors can increase the number of aux contacts. It has two styles. One is a 2-contact block, and the other is a 4-contact block, where two contacts auxiliary contact block is the front mount position and the side mount position.
Our aux contact is suitable to operate at an AC-rated operational voltage of 380V and rated current of up to 0.95 A or in a DC-rated operation voltage of DC220V and rated current of up to 15A.
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