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  • Generator to water Pump

    I have connected a 5500 watt(6250w peak) generator to my 3/4hp in-the-well water pump through an EmerGen manual transfer switch.I connect with size 10 -4 conductor wire and NEMA connectors. I measure 220 V at the pump breaker when the pump is off. When the pump switches on the watt meters on each phase of the transfer switch register 2700watts. They remain there for about 15 seconds,the pump doesn't start,and subsequently one or both of the breakers on the transfer switch trips. The transfer switch is rated at 30 amps at 250V. The pump works fine with utility line power.

  • #2
    I have the same generator (at least in rating) and a 1/2 HP well pump (230V 5 A - from sticker). I know my generator snorts pretty good when the well pump kicks on. I had a 220V 14A compressor on the generator circuit (don't ask) and it behaved the same way that your 3/4 HP motor did. It may be that the inrush current required to start you 3/4 HP motor in not available. If the gen is new you may want to return it and try something with more peak power available. The B&S Wheelhouse has 8550 surge watts which may be enough to start that pump.

    Comment


    • #3
      Originally posted by wbrooks
      I have the same generator (at least in rating) and a 1/2 HP well pump (230V 5 A - from sticker). I know my generator snorts pretty good when the well pump kicks on. I had a 220V 14A compressor on the generator circuit (don't ask) and it behaved the same way that your 3/4 HP motor did. It may be that the inrush current required to start you 3/4 HP motor in not available. If the gen is new you may want to return it and try something with more peak power available. The B&S Wheelhouse has 8550 surge watts which may be enough to start that pump.
      i agree.

      your pump is starting under a load, thus drawing possibly 2-3 times more current than when running. sounds like it's wired fine since it works with house power.

      can you test this pump or a similar pump without a load?

      a larger generator is probably needed to start this type of pump.

      rick.
      phoebe it is

      Comment


      • #4
        Generatort to Pump

        If my generator is loaded too heavily when my pump kicks in, wouldn't that show on the transfer switch watt meters? As it is,the meters do not show any variation from 2700 watts on each phase which is close to the max output of the 5500 watt generator.

        Comment


        • #5
          Do you have a way to measure starting amps when running from normal AC power? If you could get a clampmeter on a phase with a peak hold and watch during a start sequence then you would have a good idea of how much surge power you need in your generator.

          Also, if you know the manufacturer of the pump you might find some literature on their web site to help determine the starting amp draw.
          ---------------
          Light is faster than sound. That's why some people seem really bright until you hear them speak.
          ---------------
          “If I had my life to live over again, I'd be a plumber.” - Albert Einstein
          ---------
          "Its a table saw.... Do you know where your fingers are?"
          ---------
          sigpic http://www.helmetstohardhats.com/

          Comment


          • #6
            Originally posted by Piseco
            If my generator is loaded too heavily when my pump kicks in, wouldn't that show on the transfer switch watt meters? As it is,the meters do not show any variation from 2700 watts on each phase which is close to the max output of the 5500 watt generator.
            And there is your answer, you are pulling 5400 watts, the max except for a second or so which likely would not even be long enough to register on the meters. The 6250 is likely not enough juice to initially spin the pump although it would be lots to keep it spinning.

            Comment


            • #7
              How is the pump wired from the house?

              One item that comes to mind is, many pumps have a start winding and a run winding. If there are three conductors plus ground going down to your well pump, you need to ensure that your generator is feeding the well pump controller and not the pump itself.

              The white conductor going down the well is actually one of the hot conductors.

              This is my setup:
              http://img.photobucket.com/albums/v3...ipingthere.jpg
              http://img.photobucket.com/albums/v3...l/CapRelay.jpg
              http://img.photobucket.com/albums/v3...al/WellBox.jpg

              As shown in the second picture's diagram, the yellow wire (which would be white in the cord out to the well pump) is actually a hot, not a neutral.

              So, if there is a well pump controller box, you need to be sure you're ahead of it, where there are still only two hot conductors (L1 & L2).
              Last edited by Rocky Mountain Sparky; 09-05-2006, 09:41 PM.

              Comment


              • #8
                Put a volt meter on the generator and when it is trying to start, you could have a faulty voltage regulator in the generator, also double check the wiring in the transfer switch and to the pump and check to see if it is on the correct voltages when the generator is operating it.

                Does the transfer switch have any other loads on it?

                If it does do they run OK?

                Are they running at the same time?

                Is the generator lugging down when the pump trys to start?

                like said before I would check the amp draw on start up off the grid, and then check the start up off the generator, with a clamp on amp meter,

                and on small generators the surge rating is basically meaning less, It is kind of like rating a vacuum motor at 5 hp when the running amps are 10 amps/120 volts,
                they may acheave it but it would be in a direct short situation that would kill the unit,
                Push sticks/blocks Save Fingers
                ~~~~~~~~~~~~~~~~~~~
                "The true measure of a man is how he treats someone who can do him absolutely no good."
                attributed to Samuel Johnson
                ~~~~~~~~~~~~~~~~~~~
                PUBLIC NOTICE: Due to recent budget cuts, the rising cost of electricity, gas, and oil...plus the current state of the economy............the light at the end of the tunnel, has been turned off.

                Comment


                • #9
                  Generator powered water pump.

                  The pump is a 3/4hp Gould installed in 2000 but with seasonal use(about 18 months total use ).The sticker says 8 amps running draw. No info on starting draw. Does that depend on well depth? The pump is wired to the house through a pressure switch. The utility line and my generator through the transfer switch is ahead of the pressure switch(new).
                  No other loads are operating when I try to use the water pump. All 110 circuits work fine with the generator and the transfer switch(eg. lights,refrigerator,small appliances,etc.). I haven't listened to the generator when the pump kicks in-will do. I'm currently using a 600v,size 10,4 conductor cable that is about 40 ft. long from the generator to the transfer switch and may be getting some line losses. Plan to try with the same size cable only 6 ft. from the transfer switch. Will also try to obtain a clamp on amp meter to test out starting currents.

                  Comment


                  • #10
                    Voltage drop could affect startup. If you have a long run of wire to your pump, and the wiring is not sized correctly, then voltage drop would mean an increase in amp draw to supply the required wattage to the pump to start and run. Is you pump more than 75' down the well (not the well depth, since the pump is not necessarily resting at the bottom of the well)?

                    Also consider the wire size from the panel to the pump, if they are located any distance apart. For me that is about 65 ft from the panel to the disconnect just inside the house from the pump, then another 85 feet of wire to the pump down in the well. So that's a 150' run of cable for my setup.
                    ---------------
                    Light is faster than sound. That's why some people seem really bright until you hear them speak.
                    ---------------
                    “If I had my life to live over again, I'd be a plumber.” - Albert Einstein
                    ---------
                    "Its a table saw.... Do you know where your fingers are?"
                    ---------
                    sigpic http://www.helmetstohardhats.com/

                    Comment


                    • #11
                      Originally posted by Piseco
                      If my generator is loaded too heavily when my pump kicks in, wouldn't that show on the transfer switch watt meters? As it is,the meters do not show any variation from 2700 watts on each phase which is close to the max output of the 5500 watt generator.
                      Are you sure it's not a 5500W @ 240 V generator? I thought those could generate 5500W of 240 volt power.

                      The startup of the pump will be over 50A. But I would think the generator would come all the way up to 5500W (not stop halfway) when you kicked the pump on? Perhaps the generator is faulty?

                      It might not be great on the motor having a slightly undersized peak-current on the generator, but I would think it would still start spinning. I mean, inrush current is a very short event - this pump says it only pulls 8A. It goes from 0 to 50 back down to 8 again in a matter of a second and a half.

                      Comment


                      • #12
                        It is a 5500w generator at 240V. It develops 2700W on each 120 phase which when ganged together gives close to the max output of 5500W at 240V.Nothing seems faulty with the generator in view of this.Internet info from Goulds indicates a 14Adraw for this motor on startup and an 8 amp continuous draw.The pump is at the bottom of a 300 ft. well which means that it starts up with a 300 ft. head of water on it.I suppose it's possible that that might result in a much greater start up current draw.

                        Comment


                        • #13
                          IN my thinking the generator should start it,

                          I have a 3800 watt generator, and it will start my sub pump in the well (280') and I think it is a 1 hp unit,

                          and the only thing I can figure is, some thing is wired wrong, and your only getting 120 volts to the pump some how, or the generator is not generating the proper voltage or amps under heavy load, (which if it was not developing the proper volts it will not be able to developer the proper amps),

                          http://vmisales.com/voltmaster/appchart.html

                          http://www.mayberrys.com/honda/gener...quirements.htm

                          (I doubt if this is a possible problem but you could have a faulty capacitor or one that is going bad, or the relay in the pump control box, and it is not yet bad enough to show up on the grid), I would think that that if the motor/pump was developing a bad bearing or winding it would trip the breaker on the grid),
                          Push sticks/blocks Save Fingers
                          ~~~~~~~~~~~~~~~~~~~
                          "The true measure of a man is how he treats someone who can do him absolutely no good."
                          attributed to Samuel Johnson
                          ~~~~~~~~~~~~~~~~~~~
                          PUBLIC NOTICE: Due to recent budget cuts, the rising cost of electricity, gas, and oil...plus the current state of the economy............the light at the end of the tunnel, has been turned off.

                          Comment


                          • #14
                            try this to figure out your voltage drop. If you have different sections with different sizes you do each section individually and sum the drop results
                            http://www.ls.net/~windyhill/Calcs/linedropcalc.htm

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                            • #15
                              Re: Generator to water Pump

                              Please try this and report your findings.

                              Obtain an AC Voltmeter with a 0-250 or 0-300 range. This should not be a digital meter. Either a panel meter in a box with binding posts or jacks, or a good VOM like a Simpson 260 or Triplett 630 is best for this test.

                              Now with power to the pump totally shut off remove the cover on the pressure switch and connect the meter to the 2 hot wires from your source. Most likely you'll need some good size alligator clip leads. If you can't get that to work out, then you'll have to hold the test prods but with care. You're going to need a helper anyway.

                              The next part is to keep watch of the Voltmeter with the power on but the pump not running. Then with it starting and running off the regular power source. Finally try it using your generator. Please note all readings. This is both starting and running.

                              Then go to the generator and check Voltages under no load and if you can, plug in some loads into all of the 120 Volt receptacles. Portable heaters or toasters make good loads. Measure Voltage from neutral to each hot and from hot to hot at the 240 Volt receptacle.

                              Do be careful as you do not want to short out anything or get zapped. I recommend you wear a face shield just in case. If there's bright lighting (especially outside) please wear a pair of good sun glasses under the face shield.

                              Once done, you'll know better where the trouble is. You need loads of known Wattage and please do not connect them all into one receptacle. 1500 Watt portable heaters work well for this. If there's little Voltage drop running 2 of of them (one on each hot to neutral) then you can figure the generator is most likely OK.

                              What would be great (but costly) would be if you had access to a load bank tester for small generators and a good tech to check it. Then you can check Voltages and frequency under no load, light load, moderate load and full load conditions. If it passes then give it a quick (just a few seconds) at about 125% of full rated output and do a fast Voltage check. Needless to say only a good service center will have such a load bank tester. They cost some big $$$.

                              I know the above is asking a lot, but doing some Voltage tests will give answers to why this doesn't work out.

                              A 5500 Watt portable generator (unless very overated like the ones from China are) should more than be able to start and run a 3/4 HP pump.

                              Here's an idea to try if you're up to it. Try to wire the pump only for power from the generator and see what happens. Totally bypass the transfer switch and be sure that house power is 100% not connected for this test.

                              By the way the 2 meters in the transfer switch are AC Ammeters and do not measure Voltage. Also, they are the cheapo type. Good ones (2 of them) would cost about what that transfer device costs.

                              In this case you will need to measure Voltage at several points and under load.

                              If you have access to a clamp-on Ammeter like an Amprobe that's great. Using regular power you can get an idea of starting current of the pump, but you'll need one with a peak hold feature.

                              By the way if you don't have the test instruments, ask friends. Anyone that does electrical or electronics work should have an AC Voltmeter that will serve your needs. He/she may well have a good clamp-on or inline 0-30 or 0-50 AC Ammeter too.

                              Good luck with this and please post your findings. It's a real pain to not be able to run a well pump during a power failure.
                              Last edited by Woussko; 09-11-2007, 04:50 AM.

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