Contactor holding circuit with Push Button Switch


Hey, in this article we are going to see the contactor holding circuit with NO and NC push button switches. This contactor holding circuit mostly used in the motor controller or motor starter circuit such as DOL Starter, Star Delta Starter, etc. The main objective of this holding circuit is to keep the contactor On condition even we release the pressure from the NO push button switch.


Why holding circuit required with Contactor?


We know that the push-button switch used for the motor starter has a construction as that, it only makes or breaks contact when we press the switch, once we release the pressure from the switch, its contact will come to its old position.
So when we use a NO pushbutton with a contactor, the contactor will be turned on only when we press the switch. So we need to make an external connection that will keep on the contactor until we press the NC pushbutton switch.


Contactor Holding Circuit and Wiring Connection



Equipment used for this Circuit:
  • Three Pole, 440V Contactor(having four auxiliary contacts) - 1 no
  • NC Push Button Switch - 1 no
  • NO Push Button Switch - 1 no

Step 1

Make the three-phase power connection as shown in the below figure. Then connect the neutral wire with the Contactor Coil A2 terminal as shown below.

Contactor Holding Circuit Connection and Wiring 1



Step 2

Take a connection from the 'R' phase and connect the NO and NC Push button switch in series as shown in the below figure. Then connect another terminal of the NO push button switch with the contactor coil A1 terminal.

Contactor Holding Circuit Connection and Wiring 2



Step 3

Connect the NO auxiliary contact terminal with the coil A1 terminal as shown in the below figure.

Contactor Holding Circuit Connection and Wiring 3



Step 4

Connect another terminal of the NO auxiliary contact with the incoming terminal of the NO push button switch. See the below diagram to better understand.

Contactor Holding Circuit Connection and Wiring 4



Step 5

Now your connection is ready. Check your connection again with the below figure.

Contactor Holding Circuit Connection and Wiring 5



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Contactor holding circuit with Push Button Switch Contactor holding circuit with Push Button Switch Reviewed by ETechnoG on 2/16/2021 Rating: 5
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