Specs on a well pump

[ralleia]

We have a little well off the corner of our house. The pump is electric, wired to a 10-amp breaker on our breaker box in the house.

A potential opportunity has arisen to MAYBE get a small photovoltaic system installed to power the pump, in the event of power interruption. We live in a semi-rural area at the end of the above-ground power lines. A possible backup system is a big carrot--even without worries about SHTF situations, our power gets interrupted a lot. We are on city water, but water is critical enough for one to really want two or three backups.

We could really use the specs for the current wired water pump currently installed, but the pump has no face plate to make things easier. It is possible that some information could be gleaned from opening the thing up, but I don't know. The house was built around 1930, is a little old farmhouse, and I have no idea how old the well pump is.

Do you have any advice on how to proceed in getting good data for voltage and current drawn?

[ttazzman]

The easy answer is have a electrition come out and look it over but....

my first question would be is it 110v or 220v (should be able to tell from breaker)

does it function with the breaker it has now?

you will need to know the start up load on the motor (i assume its under 10amps)

if it is 110v that is only 1100watts at start up and much less when running so that is not a overly large system, if it is 110v you could use a kill-o-watt meter to see your peak and continuous demand.

it would be good to understand how long your pump typically needs to cycle to fill up your pressure tank (if you have one) etc. or if it is a "demand" style pump etc.

setting up PV panels to charge a battery bank and a 110v inverter to provide 1100w start up load pump to periodically fill a pressure tank seems very doable to me

but that is a lot of IFs

[damoc]

if you have to ask you should probably call in an electrician

honest just to be on the safe side

a visual at the box will tell an electrician whether its 110 or 220

the 10 amp circuit breaker will give you a clue as to the watt rating of the required inverter, battery bank and or solar array.the inverter may need to be a pure sine
wave which will add a lot to the cost.

for example if its 110 v look for a 110 v and about 2000 watts to be on the safe side
it would probably run on a smaller inverter but no sense running it to its limit
all the time better to have some lee way.

if its 220 volt you would be looking for a 220 volt 3000 to 4000 watt inverter.

you will also need it set up so that it can not back feed into the grid unless correctly
set up to do so safely.a grid tie inverter will add a lot to the cost

[ralleia]

Thank you. The electrician was one of the straws that I was grasping at.

It *does* currently work off the 10 amp breaker, and I'm pretty sure that it is a 110 V circuit, since all the 220/240s are double-breakers.

The pump starts up when the pressure falls under a lower bound (?30? psi), and shuts off at an upper bound (perhaps 50 psi).

I'll call an electrician and have him examine it.

[techguy2]

It may be cheaper in the long run to investigate a 12v pump. This does away with the need for an inverter system, and can pump small volumes of water will a very modest panel or two.

[horseman1]

Hi, Here is my 2 cents.

There are couple things to think about. First, we know the circuit currently works with a 10 amp breaker. This would imply that the start up current required to start the pump is less than or equal to:

120 * 10 = 1200 watts.

Nearly all electric motors and pumps pull quite a bit more current (amps) when they start up than they do after the pump starts to operate. Usually this number is more than 2X the running/continuous current amount. So, the running power requirement is quite a bit less than is required to get it going.

Most likely, you will need an inverter that provides a minimum of 1200 watts of peak power. A bit larger is always good insurance and can be useful in other applications like running some larger power tools as needed.

There are two main types of inverters. One is a true sine wave inverter and the other is a modified sine wave. The MSW inverters are much cheaper, but are not as efficient in certain applications. Electric motors are one of those applications. The modified sine wave tends to be just a little harder on the motor and the windings will get a little hotter than in a true sine wave inverter. This is because the modified sine wave has a small DC (rather than a 100% AC) component that will cause the windings in the motor to get hotter than they would with a true sine wave.

I have never had this cause a problem with the motors I have run with my inverters, but I can absolutely tell that the motor has just slightly less power and runs a little hotter than it does when plugged into the wall. So, I suspect that the life of the motor/pump could be somewhat reduced over the long haul by using a msw inverter. How much, if any would be very hard to say.

The difference in price for these two inverters can be rather dramatic.

Hope this is useful.

[spacecase0]

I have run enough motors to know that if it has a 10A breaker, its startup surge current could easy be 20A
a breaker will not care about a surge like that because they don't react fast,
but an inverter sure will care,
inverters usually have a surge start current of about 2 times the continuous rating,
so get an inverter that is at least 1200W and look for a surge current of 2400W and that may still not be enough if you get unlucky
but don't get one that has a surge current of only 1500W and a continuous rating of 1200W because they are out there.

if you want to know the true surge current,
then replace the breaker temporarily with a fast acting fuse and see if it blows with various current ratings

[Eat Beef]

If this is running on a 10 amp 110, I'm going to assume it's a jet pump, not a submersible?

Most (all that I've seen) jet pumps can be wired to run 110 or 220. 220 is much more efficient, but 110 works. I redid mine during the power outage after Ike simply because I didn't have the proper plug to run 220 off my generator, and there were none to be had. When the power came back on, I put it back to 220 on grid.

ALL of my pumps are on 20 amps or more, and most are 1hp jet pumps (Goulds) with water levels above 15'. IOW, don't plan on getting by with an 1100 watt system.

[hoarder]

It would take a fairly substantial solar system to power a 10 amp AC pump. There are 12VDC and 24VDC pumps designed for solar but they are expensive.

http://www.solar-electric.com/suscsbrdcsus.html

[horseman1]

"If it is 110v you could use a kill-o-watt meter to see your peak and continuous demand."

The kill-a-watt meter that ttazzman suggested here sounds like it would be perfect for the job. I need to get one of those...

[hoarder]

One disadvantage of DC well pumps is that their life span is shorter than AC pumps. I'm off grid and use a diesel generator to run my 240 VAC well pump. The water gets pumped into a cistern uphill and gravity flows to my house.

[techguy2]

Why not just put a manual pump head on it?

Simple pump or bison??

Simple actually makes a 12volt motor that goes on the pump, you can then run it off low voltage dc, or manually.

[Eat Beef]

Have you ever used a manual pump? Uggggghhhhhhh!!!!!!!

[ttazzman]

It would take a fairly substantial solar system to power a 10 amp AC pump. There are 12VDC and 24VDC pumps designed for solar but they are expensive.

http://www.solar-electric.com/suscsbrdcsus.html

I would think he wouldnt try to "power" it with the solar .....he would just put in enough solar to recharge his batterys between pump cycles and obviously he would need enough reserve to carry him through nights and several cloudy days etc............the pump if it is on a pressure tank may only start and run for example 5 times a day for 15min or so....my deep well submersible probably runs about like the example and if i were being conservative i doubt mine would run over once a day (i have a rather large pressure tank)