1. I didn’t realize that three phase power configurations on well pumps uses overlapping waves to provide constant power. My sister is having a home built for her family in the hills. Hopefully, she can use this info to choose a set up that can supply her family with constant water. Thanks!


  2. One of the water pumps in the city broke a week ago and it got me curious about them! I didn’t know there were different power phases for pumps before. That is really cool that the most common power phases are single and three-phase! Thank you for all the information!

  3. Miguel

    Hi We have single phase power available but we want to use a 3 phase in the pump. Is this possible. What is the life span of a 240 vs a 3 phase pump?
    Thank you

    • Brian McWhorter


      Thank you for your question. It is not possible to operate a three phase motor on single phase power without a piece of equipment called a phase converter. Digital phase converters are commonly added to variable frequency drives (VFD), and can be purchased from most motor shops or local electrical contractors. Keep in mind that if you are using a variable frequency drive, you need to either purchase a motor with a shaft grounding ring, or install a shaft grounding ring on your existing motor to insulate the bearings from stray voltage.

      Here are a couple of sites to check our for more information.


      Let me know if you have any other questions.

  4. Najam Jamal


    I have a scenario in which I have a single phase connection available.

    I need to use a centrifugal pump of 5 hp which will pull water and throw to a stream of 600 ft.

    My queries are

    1. Does single phase hold the load of 5 HP.

    2. If yes will 5 HP pump be good enough to cover the 600 ft distance.

    3. What can be the atlternative with a limitation of having a single phase connection only? Can a phase converter helpful in this scenario in order to make it three phase and use a 3 phase pump?

    Appreciate a swift response.

    Thanks & Regards,

    Najam Jamal

    • Brian McWhorter


      Thank you for your questions. Hopefully this helps.

      1. Does single phase hold the load of 5 HP.
      -5 HP motors are commonly run on single phase power. If needed, you could also easily find a 7.5 HP motor that uses single phase power.

      2. If yes will 5 HP pump be good enough to cover the 600 ft distance.
      -Aside from the distance the water needs to travel, there are a few more factors that you will need to take into account when determining the power requirements of an application. This step can be a little involved, so I would recommend that you reach out to a local pump distributor to help you with your specific application. The basic information you will need to know is required flow (GPM), total dynamic head (TDH), specific gravity of the liquid being pumped (1.0 if clean water), and pump efficiency. Your local distributor should be able to help you either find or calculate this information.

      When you have that information you can use this formula to calculate the brake HP:
      Brake HP = (GPM * TDH * specific gravity) / (3960 * pump efficiency)

      3. What can be the alternative with a limitation of having a single phase connection only? Can a phase converter helpful in this scenario in order to make it three phase and use a 3 phase pump?
      -Knowing when to use a phase converter can be a tricky decision. I recommend first doing some research to see if a single phase motor will work, and then revisiting this question if you’re out of options.

      • Najam Jamal

        Thanks Brian for prompt response.

  5. Hussain

    Very helpful information. I learned a lot from your article.


  6. What 3 phase cable size do I need to run two 5.5 KW 3 phase water pumps running in tandem at a distance of 450yards from power supply. The supply is 240v.
    Many thanks

    • Brian McWhorter


      Thank you for your question. To be able to size cable, you would also need to know the following information.
      -Amp draw of your motor.
      -Maximum ambient temperature.
      -Allowable voltage drop (usually either 3%-5% of the source voltage).

      If you are powering both motors from a single power source/cable, you would need to rate the cable for both amp draws, or double the cable size requirements of a single motor.

      Hopefully this helps.

  7. Jeff M.

    I want to install a 3 phase (208v) standby generator at my residence. The grid is a delta configuration or stinger leg. The only 3 phase equipment is a submersible well pump. Does the standby generator need to produce power with one leg as a stinger?

    • Brian McWhorter


      Thank you for your question. If the motor on your submersible pump is 3 phase, you will need to use the high-leg of your generator to operate it.

      Here is a helpful article that may explain things more completely.


      Hopefully this helps.

  8. rk

    I would like to know single phase and three phase submersible pump advantage.
    If I use three phase motor, my power cost comes down? or single phase pump will consume higher current?

  9. Manu Mark

    While using a 3 phase 5HP submersible agricultural pumpset, at times 2 phase is provided. An autostarter switch is used, which means the pumpset may run on the 2 phases and burnout.
    Please name and describe a tool to prevent 2 phase run and burnout.
    Can a protector be installed within the motor to stop it when 2 phases alone are provided?

    • Brian McWhorter


      I would recommend contacting your power provider and see why the third leg of power is being lost. There are protectors you can purchase. I would recommend Googling a electrical control panel shop in your area. They should be able to provide a control to prevent the pump from engaging when you are having power issues.

  10. jun

    I would like to ask if there is any way i can use vfd in my single phase water pump. my power source is 3 phase but the vfd available in our local store has single phase input and 3 phase output. how can i use this vfd in my single phase water pump?

    I will be appreciate your response. thanks

    • Brian McWhorter


      Thank you for your question.

      There are a few options to convert three phase incoming power to a single phase output. There are drives available with these capabilities built in, but here is a quick summary of a few ways the conversion could take place.

      1. Convert the incoming three phase AC power to DC using an electronic rectifier, and then convert the DC power to single phase AC using a single phase inverter.
      2. Use a single phase transformer across two phases of the incoming power. This is only acceptable up to about 400 volts.
      3. Use a open delta transformer. Using this transformer effectively double the acceptable voltage rating as compared to a single phase transformer.

      I recommend talking to a local control shop for their recommendation. All of these options should be reviewed and implemented by an experienced electrician.

      Have a great day!


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