MPC minipump polarity

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  • uwe123
    Ensign
    • Aug 2010
    • 8

    MPC minipump polarity

    Hi Kevin,

    first thank you for your neat little designs!One question...I have a MPC with a mini snort pump.In the instructions it is mentioned that the pump motor has a specific + terminal.This + terminal is not indicated on my pump.Can/should I solder the MPC unit onto the pump regardless what polarity and if by murphys law it is the wrong way around just switch the tubing hose?
    Thanks for your help,regards Uwe
  • KevinMc
    Commander
    • Feb 2009
    • 305

    #2
    Hi Uwe,

    The small LPB pumps available through Caswell should have a polarity marking on them, but I admit that it's not the easiest thing to see. If you look in the round, molded "holes" in the black end cap one of them should have a raised "+" molded in the bottom. That one marks the positive terminal. (I show it highlighted with white ink in my instruction manual so you can easily see it, but it's actually just a raised mold line with no difference in colour.)

    The good news is these pumps will still work regardless of which way you connect them, I'm just not sure if the brushes are timed to provide better performance or life with a particular polarity/direction. Because it's is a diaphram pump the IN port is always the IN port, and the OUT port is always the OUT port no matter which way the motor turns.

    Does this help?

    KMc
    Kevin McLeod - Oscar II driver
    KMc Designs

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    • uwe123
      Ensign
      • Aug 2010
      • 8

      #3
      Hi Kevin,

      wow--thanks for the quick reply.Ok it does help--the pump will function either way.But honest to god and I had my eyes lasered 2 years ago with 20/20 :-) ----there is NO polarity sign in sight anywhere on the motor no matter how and at what angle against the light you look at it.Anyways,on an other thread I read one can save a receiver channel by hooking up the pump with a Y lead together with the gas blow servo.Is that right?

      Regards and thanks,Uwe

      Comment

      • He Who Shall Not Be Named
        Moderator
        • Aug 2008
        • 12256

        #4
        Originally posted by uwe123
        Hi Kevin,

        wow--thanks for the quick reply.Ok it does help--the pump will function either way.But honest to god and I had my eyes lasered 2 years ago with 20/20 :-) ----there is NO polarity sign in sight anywhere on the motor no matter how and at what angle against the light you look at it.Anyways,on an other thread I read one can save a receiver channel by hooking up the pump with a Y lead together with the gas blow servo.Is that right?

        Regards and thanks,Uwe

        Uwe's right, Kevin. I too have gotten some of those pump-motor units without the '+' stamp on the back plate. Go figure.

        Anyway ...

        ... Uwe: No, you can't use the Y connector now as Kevin's re-written the code to turn the his electronic switch 'on' during the majority of the pulse, not just a portion of it (which permitted piggy-backing of the LPB with the ballast gas-subsystem servo possible). You now need a dedicated channel.

        David,
        Who is John Galt?

        Comment

        • uwe123
          Ensign
          • Aug 2010
          • 8

          #5
          OK thank you very much for this input Dave.Now everything is clear and nothing should go wrong with the pump.

          Have a great day, Uwe

          Comment

          • He Who Shall Not Be Named
            Moderator
            • Aug 2008
            • 12256

            #6
            Thank you, Uwe. Keep us informed on how it goes.

            David,
            Who is John Galt?

            Comment

            • uwe123
              Ensign
              • Aug 2010
              • 8

              #7
              Feed back,

              soldered the pump motor to the controller plate and it all works fine.Since it really is just a simple electric motor it shouldn't have an impact as to where is plus and minus anyway.Just wanted to be shure beforehand.Thanks again,Uwe

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