Star Delta Starter Connection Diagram and Wiring


Star Delta Starter is a widely usable starter for a three-phase Induction Motor. In this article, we are going to see Star Delta Starter Connection Diagram and Wiring. Here we will see how to make a power circuit and control circuit. Also, we will see how to do a timer connection with the star and delta contactor. The connection diagram of Star Delta Starter consists of the following devices,

  • Three Pole MCCB - 1 Nos
  • Single Pole MCB - 1 Nos
  • 440 V Three Pole Contactor - 3 nos
  • Three Phase Thermal Overload Relay - 1 Nos
  • 220V On Delay Timer - 1 Nos
  • NC Push Button switch - 1 Nos
  • NO Push Button switch - 1 Nos
  • 220V Indication lamps - Red, Green, Yellow

Star Delta Starter Connection and Wiring


First, let's make the power circuit. Here you can see the wiring diagram for the power circuit of the star-delta starter.

Star Delta Starter wiring connection diagram, wiring for star delta starter






How to Do Connection

1. First connect all three phases of the main incoming power supply to the MCCB. Most of the MCCB allows connecting the input power supply at any side top or bottom. But if your MCCB is already identified for connecting the input power supply at a specific side top or bottom, connect according to its identification.

2. Connect the output of the MCCB to the input of the Main Contactor also take a loop and connect the Delta contactor as shown in the above diagram.

3. Connect a thermal overload relay with the main contactor as shown in the above diagram.

4. Now, you have a total of six terminals to connect with the motor three from the output of the OLR and three from the output of the delta contactor. Connect those all terminal with the motor as shown in the above diagram.

5. Now take a loop from the output of the delta contactor and connect with the Star contactor. Also, short the all three terminals of the star contactor as shown in the above diagram.

Now our power circuit is complete. Now we are going to make the control circuit with a timer, push-button switches, etc.

Here you can see the connection diagram of star delta starter with both power and control circuit.

Star Delta Starter Connection Diagram and Wiring, connection of star delta starter






Connection Procedure


Push Button Switch Connection

1. Take a single pole MCB as a control MCB and connect it with any one phase here we have connected with the 'R' phase.

2. Connect the output of the MCB to the STOP or NC push-button switch through the NC contacts of the OLR as shown in the above diagram.

3. Connect the output of the NC push button switch with the START or NO push-button switch. Also, connect the output of the NC push-button switch to the A1 terminal of the main contactor through the NO contacts of that contactor. It makes the holding circuit.

4. Connect the output of the NO push-button switch to the A1 terminal of the main contactor.


Timer Connection

1. In this On delay timer, A1, A2 are the power terminal. 15 is common, 16 is NC, and 18 is NO.

2. Connect the A2 terminal with neutral. Connect the A1 terminal to the output of the NO push button switch as shown in the above figure. Also, make a short between the A1 and terminal 15.

3. Connect terminal 16 of the timer to the A1 terminal of the Star contactor through the NC contacts of the delta contactor as shown in the above figure.

4. Connect terminal 18 of the timer to the A1 terminal of the Delta contactor through the NC contacts of the Star contactor as shown in the above figure.


Indication lamp Connection

1. Connect any one terminal of each lamp with the neutral as shown in the above figure.

2. Connect the Yellow lamp to the NC terminal of the OLR as shown in the above figure.

3. Connect the Green lamp to the NC terminal of the main contactor as shown in the above figure.

4. Connect the Red lamp to the NO terminal of the main contactor as shown in the above figure.


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Star Delta Starter Connection Diagram and Wiring Star Delta Starter Connection Diagram and Wiring Reviewed by ETechnoG on 5/13/2021 Rating: 5
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