Design DOL / Star-Delta Starter


  • Calculate Lock Rotor Current.
  • Calculate Motor Starting Current.
  • Calculate Motor Full Load Current.
  • Calculate Non-time Delay/Time Delay fuse Size.
  • Calculate Circuit Breaker Size.
  • Calculate Overload Relay setting.
  • Calculate Type of Contactor.
  • Calculate Size of Main Contactor.
  • Calculate Size of Star Contactor.
  • Calculate Size of Delta Contactor.
  • Standard Arrangement of Main and Auxiliary Contactor

Free Download


About Jignesh.Parmar
Jignesh Parmar has completed M.Tech (Power System Control), B.E(Electrical). He is member of Institution of Engineers (MIE) and CEng,India. Membership No:M-1473586.He has more than 16 years experience in Transmission -Distribution-Electrical Energy theft detection-Electrical Maintenance-Electrical Projects (Planning-Designing-Technical Review-coordination -Execution). He is Presently associate with one of the leading business group as a Deputy Manager at Ahmedabad,India. He has published numbers of Technical Articles in “Electrical Mirror”, “Electrical India”, “Lighting India”,”Smart Energy”, “Industrial Electrix”(Australian Power Publications) Magazines. He is Freelancer Programmer of Advance Excel and design useful Excel base Electrical Programs as per IS, NEC, IEC,IEEE codes. He is Technical Blogger and Familiar with English, Hindi, Gujarati, French languages. He wants to Share his experience & Knowledge and help technical enthusiasts to find suitable solutions and updating themselves on various Engineering Topics.

20 Responses to Design DOL / Star-Delta Starter

  1. MAHESH LAL says:

    sir, i have read that a single phase motor will be only upto 2 HP….also DOL starters are use for 3 phase motors upto 5 HP…then why did u design a DOL starter for a single phase 3 HP motor??

    • Selection of all Parameter shown in Sheet are just Demo only..You can select it according to your requirements..
      By the way Who told you that DOL is used up to 5HP only !!!!..any 1Phase motor are available up to 2HP only !!!!

  2. mozes says:

    Thanks for your great work, man..

  3. Jigyansu kumar sahu says:

    what is the formula for Volatge regulation of 11KV distribution line .suppose we have 3MVA 33/11KV s/s and we have to give power supply to the 200KVA ,11/0.4 s/s for industrial load(Proposal ) and it is covered 0.2KM .so what is the volage regulation for that proposal point ?

  4. hitendra kaiwart says:

    Thanks for your great work, sir

  5. vineet says:

    very helpfull

  6. sathis kanna says:

    thanks for your information and very useful in electrical student

  7. Usha Yemul says:

    Thank you very much Sir for all these information in one stoke!!!! i m grateful to you.

  8. Nikky says:

    Hi Sir,

    Is the calculation on the blog or theres a download link? I cant seem to see the download link.

  9. Karthikeyan says:


    I am willing to learn electrical. Basically i am instrumentation engineer. i am not able to find a right way to learn about electrical. Please guide me where should i start from.

    Thanks & Regards,


  10. laxmikant deshpande says:

    u r realy great sir……….

  11. mansukh makwana says:

    Hi sir
    thank you very much sir for all quastion & answer information in one stock……
    i am GREATFULL to YOU.

  12. sathish says:

    sir ur calculation for dol & star delta download as deleted by user it showing.
    pls tell me how to get this……..

  13. pawan says:

    what is the suitable relay for 15 hp star delta motor

  14. Deepak Jagtap says:

    please provide estimation and BOQ excel sheets and softwares

  15. Richard Robinson says:

    I have an air compressor that has a Wye Start Delta Run start up. While doig some current tests we noticed 40 Amps more leaving the contactore than coming in on the mains. I would like to send you an attachment to better explain what we are showing but when you add what is going out on the two conactors it is more than what is coming in on the main conductors (one set of three). Can I send you my drawing?

  16. ahmed says:

    thank you very much for great work

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