submersible well motor voltage

Discussion in 'Pumps and Tanks Well Forum & Blog' started by gbutts, Jun 12, 2012.

  1. gbutts

    gbutts New Member

    Messages:
    6
    Location:
    Milwaukee, Wi
    recently had submersible well motor failure and motor was replaced with what was supposed to have been the same type motor. However the new motor is a 5 hp single phase 230 volt. The line voltage is 208 volts. I understand I will need to install a buck boost transformer to make this work - however well has been working for 11 years on 208 volts, I am told no motors at 5hp are made at 208, -- where 208 volt motors made in the past? I can not belive that motor would have lasted 11 years with the kind of amp draw I am seeing now.

    Any thoughts
  2. ballvalve

    ballvalve General Engineering Contractor

    Messages:
    3,261
    Location:
    northfork, california
    208 volts is common for certain 3 phase motors. Many of them are wired to accept 208, 230, 240 input volts.

    Now, yours seems to be single phase, but submersible motors are wired to survive where other motors would fail under low voltage. I have a 1.5hp running on 210 volts for many years. A transformer would be a good investment.
  3. gbutts

    gbutts New Member

    Messages:
    6
    Location:
    Milwaukee, Wi
    Thanks -power has always been single phase 208, I plan on adding the transformer. I am just trying to figure out how the old pump ran for 11 years with no problem and now I am constantly popping the reset due to high amp draw. Was just curious if there was a single phase 208 pump motor at one time so that mystery could be solved
  4. valveman

    valveman Moderator Staff Member

    Messages:
    4,466
    Location:
    Lubbock, Texas
    That motor will run fine on 208 volt. The voltage is not the problem, the amperage is. You can restrict the flow of the pump, the amps will drop, and probably stop tripping the overload. You can restrict it with a ball valve, gate valve, or a smaller diameter piece of pipe before the pressure tank. You may not have to restrict it much to keep it from overloading. If it had a Cycle Stop Valve, it would be restricted and pulling lower amperage all the time, unless you opened up and used too much water at one time.

    Could probably also increase the size of the running capacitor. Just have to be careful not to oversize it and cause high voltage.
  5. ballvalve

    ballvalve General Engineering Contractor

    Messages:
    3,261
    Location:
    northfork, california
    So we would assume the wire is undersized or the motor is too large. Fix one and you have another solution. What exactly is your application for this big pump?
  6. gbutts

    gbutts New Member

    Messages:
    6
    Location:
    Milwaukee, Wi
    pump supplies a shopping centers lawn sprinkler system - seemed large to me as well but well company tells me they replaced what they pulled out. When they replaced the pump they also put in a new control box, the new box had a 230 volt relay that kept burning up and popping the circuit breakers. They replaced the 230 volt relay with a 208 and it no longer burns out or trips the circuit breaker, now occasionnly it will pop the overload and putting on an ammeter it is pulling over spec.

    I am not overly familar with wells so I relied on the vendor and they swear they replaced like for like and problem is not thiers. I just want to get the system operating reliably before I loose to much landscape.

    Did the previous suggestion of putting in a valve or reducing pipe size make sense to you?
  7. valveman

    valveman Moderator Staff Member

    Messages:
    4,466
    Location:
    Lubbock, Texas
    If there is no pressure tank and a relay just turns on the pump with the sprinklers, you can just reduce the size of the sprinkler zones. Reducing the amount of water produced will lower the amperage. Either that or use a valve of some kind to restrict the flow from the pump.

    Submersibles are made to run at the maximum service factor load using 230 volts. So when running on lower voltage, you need a smaller pump, bigger motor, or restricted flow to keep from overloading the motor.
  8. DonL

    DonL Jack of all trades Master of one

    Messages:
    4,129
    Location:
    Houston, TX

    If Your Line voltage is only 208 and you live in the USA then you need to call your power company and have them fix it.

    If you get a step-up transformer and then they get the original problem fixed, then you will be over voltage.

    A buck boost transformer is NOT a good fix if you are paying for electric power.

    They can install a new pole pig, if yours does not have the taps needed.

    The motor may run at 208, but if you have 208 at the top of the well then you have less at the motor, depending on depth and wire size.
  9. ballvalve

    ballvalve General Engineering Contractor

    Messages:
    3,261
    Location:
    northfork, california
    Test the service entrance. Possibly 480 3Phase and a bad step down transformer to the pump. If its at 240V then the wire run is undersized to the pump. What are your STATIC volts at the pump NOT runnning and when running?

    smaller motor -no?

    More zones is the quickest, I would guess.
    Last edited: Jun 16, 2012
Similar Threads: submersible motor
Forum Title Date
Pumps and Tanks Well Forum & Blog Properly Cooled Submersible Pump motor Jan 5, 2014
Pumps and Tanks Well Forum & Blog Replacing submersible - Aermotor, Franklin, Myers, Sta-Rite? PVC or metal drop pipe? May 6, 2013
Pumps and Tanks Well Forum & Blog High Amperage Draw from Submersible Pump Motor Aug 17, 2010
Pumps and Tanks Well Forum & Blog Submersible pump motors Jun 17, 2010
Pumps and Tanks Well Forum & Blog Need help with submersible pump/motor selection Jun 13, 2009

Share This Page