How much current should a

Discussion in 'General Discussions' started by Eric D, Jan 15, 2008.

  1. Eric D

    Eric D Member

    How much current should a ½ hp well pump draw?

    I have a geothermal unit that runs with an open loop using my well. My well pump is rated ½ hp. If I measure the current draw with an a/c clamp current meter I get 6.34 amps. I’m not sure why it is this high. If the well pump is a ½ hp this means that it should draw about 373 watts under working load. This would be about 1.62 amps @ 230 volts. This concerns me that I’m getting 6.34 amps. Questions I have, am I missing something in how this is calculated, has someone replaced the pump with a larger unit, or do I have a short somewhere? Can someone explain what is normal and how to measure the current on a well pump?


    Eric D:confused:
  2. Eric D

    Eric D Member

    I learned what I was seeking to find. The major question I had and now have the answer, my pump is drawing the current level it should be. Below is the specification for my submerged well pump.

    Submersible Pump Motor, Capacitor-Start, Totally Enclosed Nonventilated, 1/2 HP, 3450 RPM, 230 Volts, 1 Phase, Service Factor 1.60, Full Load Amps 5.0/3.5, Max SF Amps 6.0/4.3, Thrust Rating 300 Lb, Number of Wires 3, Thermal Protection Auto, Mounting NEMA, Diameter 4 In, Control Box Required 1LZV8, Amps for CSIR/CSCR Control Boxes 6.0/4.3

    Note the S.F. amperage rating, 6.0/4.3. This confused me at first why there were two numbers. Long story short I ended up talking with a Franklin pump engineer. All of these pumps have a matching control box that is installed at the same time as the pump and they are a matched set. In the case of my pump they offer two types. One uses capacitor start, induction run, and the other capacitor start, capacitor run. The induction run control draws 6.0 amps, this is the one I have, and the capacitor run control box draws 4.0 amps, the one I want! I’ll be placing an order for the control that uses CSCR to replace my current CSIR box. According to the Franklin engineer there is no loss of pump performance changing to CSCR.

    Changing to the lower amperage controller will have a payback in less then a year in electricity usage.
  3. mbartosik

    mbartosik New Member

    more info required

    Eric, that amount of power does seem crazy to me unless you have a very deep well. I have my 3/4 HP (over sized - ideally would be 1/2 HP) running at about 1.8A, and I could probably get it down to 1.6A while maintaining flow (7GPM) if I tweaked a little more.

    I have asked you a series of questions on another thread.
    If I don't post back to you, then email me at mbartosik at yahoo dit com

    Also what is the make and model of well pump controller?
  4. Eric D

    Eric D Member

    Well Pump Controller

    The controller I currently have is the 1LZV8 and the one I'm replacing it with is a Franklin 1LZX3 or part number 2824055015. This is the CSCR unit.


    Eric D
  5. Eric D

    Eric D Member

    I have installed the new CSCR controller. It reduced the 6.4 amp draw down to 4.8. I think it reduces flow ever so slightly compared to the CSIR model, but not enough to be an issue.

    Eric D

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