Auto Selection of any Available Phase, in 3 Phase Supply System

Model: 173

Solderable DIY project kit for Engineering & Diploma students Worldwide

Do-It-Yourself Kit :

Includes complete hardware comprising of discrete components, modules, PCB, controller etc. and tested program code for building the project. Extensive documentation for project execution including step-by-step instructions for Circuit building, Assembly procedure and Troubleshooting. (Tool kit-Multimeter, Soldering iron and program burner not included in the kit)

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The project is designed to provide uninterrupted AC mains supply i.e., 230 volt to a single phase load. This is achieved by automatic changeover of the load from the missing phase to the next available phase in a 3 phase system.

It is often noticed that power interruption in distribution system is about 70% for single phase faults while other two phases are in normal condition. Thus, in any commercial or domestic power supply system where 3 phase is available, it is advisable to have an automatic changeover system for uninterrupted power to critical loads in the event of missing phase.

In this system auto selection is achieved by using a set of relays interconnected in such a way that if one of the relay feeding to the load remains energized always. Under the phase failure condition the corresponding step down transformer secondary delivers zero voltage which is duly rectified to DC and then fed to the logic gates comprising of AND & OR to switch on the next relay that delivers the power to the load.

It also has a provision of connecting to an inverter source which delivers uninterrupted power to the load incase all the 3 phases go missing. The project is supplied with three transformers connected to the 3 phases supply.

Further the project can be enhanced by incorporating power semiconductor devices such as thyristors/IGBTs for instantaneous changeover to the next available phase. This overcomes the drawback of the changeover time generally witnessed by relay switching operations.


Easy to use, Self-explanatory kit.

All-inclusive solution kit.

Extensive audio-visuals available.

Branding-free material.

Automatic Power Source Selection.

Call/mail for Tech Support from 10 am – 7 pm.

Can be Customized for Arduino, Raspberry Pi, PIC

Non Microcontroller.


Hardware Requirements

  • Transformers
  • Logic Gates
  • Resistors
  • Capacitors
  • Relay Driver
  • Relays
  • Diodes
  • Lamp

Software Requirements

  • None

Q & A

Buyer Feedback

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  1. Rated 5 out of 5

    K.S. Zubair

    I was suggested this website through my seniors. Because most of my senior suggested to buy project here itself,especially i like way of presentation of ppt slides. purchased through online myself. Right now everything is going fine with my project.

  2. Rated 5 out of 5


    I have question regarding the project If, im using R phase from three phase supply which is auto selected by the device Q) what happens during overload condition or during peak time,if there is fault on R phase(which im using) Then which phase is auto selected by the device, as other phases i.e Y & B are at overload condition Q) Is there any effect of overload condition

  3. Rated 5 out of 5

    Rohan Atre

    The kit was delivered on time.I am satisfied with the kit.The kit is in working condition.I will recommend you to my friends because everything in the kit is perfect.

  4. Rated 4 out of 5

    Chottani Milan

    I come to know about Edgefx through Google . I used Ready Made kit project for 8th semester as a keyword in the Google.I like everything in my kit.Yes the kit delivered on time.I directly purchased through online.No Suggestions.

  5. Rated 4 out of 5

    Sravan Kumar Reddy

    The project is working very well. I have gained some important points about this project by watching the audio visuals and the other materials provided along with this project.