STAR-DELTA Automatic Electrical Circuit Example - Navigasi Berita a -->
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STAR-DELTA Automatic Electrical Circuit Example

Navigasi - For those of us who study or work in engineering, especially industrial electricity, it must be familiar to hear about the STAR-DELTA circuit or often called the Star-Triangle circuit.

The STAR-DELTA circuit serves to dampen the surge in electric current that occurs when the electric motor is turned on (operating).

While the system used is a combination of two series of electric coils, namely STAR and DELTA as shown below.

STAR-DELTA Rangkaian wire series/coils
STAR-DELTA Rangkaian wire series/coils


Which when the electric motor is turned on it will operate using the STAR electric coil circuit then a few seconds the timer will work and change the DELTA coil circuit system.

The single circuit / wering is as below:



Picture of Star Circuit - Delta
Picture of Star Circuit - Delta


Materials needed:



  1. Push button off: 1 pcs
  2. Push button Start: 1 pcs
  3. Contactors : 3 pcs
  4. Timer: 1pcs
  5. Pilot lamp : 3 pcs
  6. Breakers: 1 pcs
  7. MCB : 1 pcs
  8. Overload : 2 pcs


Description of the STAR - DELTA circuit code


for the code in the series in the image can be seen below so that you can easily understand or assemble it

  1. Off : push button off
  2. On : push button Start
  3. NC: Normaly closed (in normal condition / not working it will be connected when tested)
  4. NO: Normaly Open (in normal condition / not working, it doesn't connect when tested)
  5. K/C: contactor
  6. T : timer
  7. NC K1 : NC contactor 1
  8. NO K1 : NO contactor 1
  9. NC T : NC timer
  10. NO T : NO timer


STAR DELTA circuit work system

for the working system of the star delta electric motor circuit is as follows

  • When the push button on is pressed, contactor 1, contactor 3 and the timer will work (the electric motor operates in a series of STAR coils).
  • Then NO K1 will lock and the timer will count/operate.
  • When the timer runs out, the NC timer will be disconnected so that K3 turns off
  • Then K2 will operate because NO T is connected and then locked by NO K2 (the electric motor operates in a series of DELTA coils)
  • Meanwhile, to turn it off, it is enough to press the push button off because it will cut off all connected electric currents.

In addition, I added a series of STAR-DELTA (Japanese version of the drawing style) below.

Star-delta circuit
Star-delta circuit


I added another picture of the automatic STAR - DELTA circuit:

STAR - DELTA Automatic circuit plus lamp
STAR - DELTA Automatic circuit plus lamp


Thank you, Agung Setiawan, who has given a picture of the circuit, that's a few things about the Star delta electric motor circuit, hopefully it will be useful for you and thank you for visiting our blog.
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