115 or 230?

Discussion in 'Pumps and Tanks Well Forum & Blog' started by juggalo6, Mar 1, 2008.

  1. valveman

    valveman Moderator Staff Member

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    Even though you are feeding a 230 volt motor with 115 volts, it is still at 60 cycles and wants to spin the motor at 3600 RPM. The low voltage doesn’t supply enough power to do that so it never gets to full speed. The difference between the RPM that the power is trying to spin the motor and the actual RPM is called “slip”. The more slip, the more the rotor bars are passing through lines of magnetic flux, and the more heat it produces.

    Add to that a motor on a jet pump is air cooled with a fan, and the fan is not spinning at optimum speed.

    A submersible motor is water-cooled and can take it for a longer period of time. But it is always advisable to keep the voltage within plus or minus 10% of the rated voltage for the motor.
  2. DonL

    DonL Jack of all trades Master of one

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    The pump motor may run on 115 when wired for 230, but may not for very long before it trips the internal overload. If the motor does not get up to the proper speed, Heat will normally result, Sometimes you make smoke.

    A PWM drive would be a better choice if you need to slow down the motor a bit. But why would You need to ?
  3. FrustratedinNJ

    FrustratedinNJ Member

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    Location:
    NJ
    This is long-winded, but you asked so here's your answer.

    First of all, thanks to you and valeman for your replies and good info. Now I know that the motor is running hotter. And why.

    To answer your question, it's related to my only other thread on this site earlier this year. My question on that thread was (or became) whether or not pumping with a jet pump causes movement in the pipes and jet body in the well.

    I think I now have confirmed the answer that I previously believed to be the answer.

    Here's the deal: My well is an older well that was probably drilled in the 40's or earlier. It's a standard 6" well which was drilled at least 70+ feet deep (that's all the rope I had) and the plastic pipes in the well are 60 ft long. So I'm drawing water from 60 ft down.

    The problem is that I was told 30 years ago by a well guy who supposedly "knew" this well that "there's only 20 feet of casing in the well."

    I take that to mean that there's just one length of casing in the well. I think casing actually came in 22 ft lengths, but whatever.

    That conversation was prompted by the failure of the foot valve just after my last ex-wife and I bought this place in 1982. I pulled the pipes out of the well and replaced the foot valve back then and all was fine.

    That FV failed last January and I foolishly pulled the pipes out on Jan 12 just prior to the really cold weather setting in. So the pipes were out and I suspect that these freaking plastic pipes developed a bend at the end which is likely causing my problem now.

    Which is that if I run my pump normally it pumps like a freaking fire hose. I guess that's causing the jet body down in the well to move around and stir things up, probably banging against the uncased well wall, as a result of which I get sediment in just about all the water I pump. Sometimes it's pretty clear and sometimes it's very brown.

    I'm in NJ (the "red clay" State in my area) and the sediment is this reddish-clay/reddish-shale color.

    I also am not using any pressure tank. I run the pump with a standard light switch and capture the water in gallon jugs, 5-gallon bucket(s), whatever.

    Don't ask.

    So, it occurred to me that if the fire-hose pumping is causing the stirring down in the well, perhaps slower, more gentle pumping would help.

    And it looks to me (so far) like it has. The water I've pumped so far looks to be sediment free. If not completely sediment free, it's definitely got much less sediment in it.

    So that's why I wanted to slow things down when pumping.

    Now, granted that this is not a practical solution for a normal human situation, but it works fine for me. Note that I deadheaded the output line (shut the faucet off) and ran the pump wired for 230v and it developed only 12 lbs pressure. When run deadheaded wired properly it goes right up to 60 lbs whereupon the pressure switch shuts the pump off, as expected.

    One other thing to note is that I was somewhat surprised that pumping at what appears to be a very gentle rate poses no pumping problem at all. I figured maybe the foot valve might not open and/or the nozzle/venturi combination wouldn't work to actually cause water to pump. But I'm doing it just fine, so I guess maybe I could pump at regular speed with much larger nozzle and venturi orifice(s) than what I have now and what is recommended. In fact, my venturi has a larger orifice (hole, opening, whatever) than is recommended at this depth. Same is true of the nozzle.

    The obvious solution is to either have a new well drilled, or have more casing installed (which is probably tantamount to having a new well drilled) or drop enough plastic casing down the well (which is apparently ~5.5" OD, and thus would drop down the well) to make up the difference in the missing area of casing, and thus "case" the well in the area of the jet body. That would probably work. But that casing is pretty expensive and if it didn't work, it would just be wasted money.

    The other possible solution is also expensive. That would be to put an in-well pump down there and hope that it wouldn't stir things up to the point that would result in sediment.

    But keep in mind that I have that bend in the pipes down there that I don't think was there before, and thus any pump or foot valve might well end up resting against the uncased well wall, and thus suck in sediment any time I'm pumping water.

    BTW, my rate of pumping is currently about 16 seconds / gallon. It's nice and slow and gentle. Normal rate is like 4 seconds / gallon.

    I just can't believe that the morons who drilled this well didn't put casing in all the way down to the point where they were drawing water. And then some more beyond that.

    You can't make this stuff up.
    Last edited: Aug 7, 2014
  4. DonL

    DonL Jack of all trades Master of one

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    If it is a jet pump, and a shallow well, you should be able to just kill or lower the volume and pressure that the jet is getting.

    Some pumps have a regulator to control what the jet gets.

    Maybe I am confused. But seems like you have better ways to control water flow. Running a motor on the wrong voltage is not a very good remedy. Me thinks.


    Have Fun. Be safe and adjust your fuse rating and wire size for your new operating voltage.
    Last edited: Aug 7, 2014
  5. FrustratedinNJ

    FrustratedinNJ Member

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    32
    Location:
    NJ
    The regulator doesn't control water going to the jet. It controls water flow to the pressure tank only. Because I'm not using a pressure tank I have plugged the outlet on the pump that would normally feed water to the tank. Thus my pressure regulator has no effect whatsoever.

    Thus there is no way to control either the pressure at which the system operates or the flow of water to the jet, practically speaking.

    Of course, if I were to have larger outlet pipes running to my faucet, that would reduce the pressure throughout the system while the pump was running. I have standard 1/2 inch copper piping in the house now.

    But that's not a practical solution, especially since the outlet hole on the pump is something like a 3/4 inch threaded hole, or maybe 1 inch max, and that would obviously limit the flow no matter how big the pipe attached to it.

    So there is no way to control water flow to the jet, or the pressure at which the system operates, other than to slow the pump down. Which is why I'm doing that.

    Why do you suggest that I adjust my wire size, what adjustment are you suggesting I make, and what wire are you referring to?

    I understand that the pump is running hotter and valveman explained why that is, but what does that have to do with my wiring to the pump? I can understand that the wire in the windings could be damaged if the pump runs too hot, but that wouldn't seem to have anything to do with the wiring to the pump.

    Or the fuses, for that matter.

    Which leads me to my next question: Could I be damaging my pump by running it this way -- assuming I just run it for short periods so that it only gets warm and never gets hot?

    Anyone have a thought on that?
  6. valveman

    valveman Moderator Staff Member

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    Lubbock, Texas
    Yes running at half the voltage will hurt the motor. And you are probably still pumping sand. It is just that at 4 GPM, the velocity in the drop pipe is not fast enough to bring the sand up. So the sand just settles back down on the foot valve, which will cause another foot valve problem.
  7. LLigetfa

    LLigetfa DIYer, not in the trades

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    NW Ontario, Canada
    Many jet pumps have a choice of different size jets to tune the pump to the well. Of course, you could also use a simple dole valve to slow the GPM but I suspect valveman is right, that the sand is still getting sucked up but the lower velocity keeps it from reaching the top.
  8. FrustratedinNJ

    FrustratedinNJ Member

    Messages:
    32
    Location:
    NJ
    Thanks for the reply. Can you give me a little more information on how running the motor this way will hurt it?

    What kind of damage am I doing to it by running it this way?

    And what kind of long term effect might I expect if I keep running it this way?

    I don't want to damage the motor and have to replace it.
  9. FrustratedinNJ

    FrustratedinNJ Member

    Messages:
    32
    Location:
    NJ
    I don't think "sand" is really the right term to use in my situation. But regardless of what term we apply to the sediment I've seen, I find it hard to believe that running the pump at this slower speed is stirring things up the way it does when run at full speed. So assuming that I am still pumping the sediment, I seriously doubt that I'm pumping as much sediment as I was before.

    That is to say, I think the main problem I've had up to now is that the vigorous pumping I get at full pump speed is causing the jet body (and pipes in the well?) to move around and stir things up thus causing the sediment I've seen in my water. I think it's obvious that more gentle pumping is going to cause less movement in the pipes and jet body and thus less stirring up and thus less sediment.

    Pumping less sediment now means less sediment settling back down.

    Pumping at full speed means more sediment and thus more sediment settling back down.

    That's my take on things.

    I guess your take is that I'm pumping just as much sediment now as before, but because the flow is reduced it's not "reaching the top"?

    That means I'm getting more sediment settling back down than I was before.

    I don't see it that way at all and I doubt that's what's happening.

    Now, if someone can tell me that a jet pump doesn't cause movement in the pipes and/or the jet body down in the well, then I'd have to re-think things.
  10. DonL

    DonL Jack of all trades Master of one

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    When you cut the voltage in half, You double the current. You need bigger wire for 120 than 240V. The motor windings could burn out because you do not reach the motor operating speed. It needs to run at operating speed or the field and armature are not phased properly, That makes heat, and smoke.

    If it works for you, then do it.

    Just add more smoke when some comes out.
    Last edited: Aug 8, 2014
  11. LLigetfa

    LLigetfa DIYer, not in the trades

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    Location:
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    I seriously doubt that physical movement of the assembly in the well is responsible for disturbing the sediment but rather the the GPM rate of pumping that is motivating it. Reducing the GPM by any means is likely to affect it.

    Pumping a well at a very high GPM rate is a common way of developing. The idea being that overpumping clears out the sediment and that later pumping at a lower GPM no longer motivates the sediment. Some wells however not stop producing sediment regardless.
  12. FrustratedinNJ

    FrustratedinNJ Member

    Messages:
    32
    Location:
    NJ
    I should point out that when I last put the pipes back down the well, with the new foot valve installed, I was aware of the bend at the end of the pipes and the problem that could cause because it could mean the foot valve might come to rest against the uncased wall, thus sucking sediment as a matter of proximity. Now, maybe that bend was always there, but I don't think so.

    I never had this sediment problem before I pulled the pipes in January. So I'm guessing that the old foot valve was more centered in the well than is possible now because of the bend. And although I did try to straighten the bend, my effort didn't appear to have much success.

    So to help with that problem I installed something to prevent the foot valve from resting against the well wall and thus keep it at some distance away from the wall. I think that gizmo did it's job, and things would be just fine if everything down in the well was stable when pumping.

    But I didn't take into account the problem I'd have if pumping caused movement, particularly significant movement, in the jet body and/or pipes in the well. In that event, the gizmo, presumably resting against the well wall, would simply beat against the well wall and stir things up, creating sediment in the well.

    That seems to be the case and thus my goal now is to minimize that movement as much as possible, and thus hopefully pump essentially sediment-free water.

    I seem to have accomplished that goal, given the clear water I'm now getting. But if I am still pumping sediment, I really don't think I've made the sediment problem worse because there's more sediment settling back down now than before. I think I'm pumping less sediment now because there's less sediment being stirred up when pumping at this more gentle rate. Because gentler pumping equals less movement in the pipes/jet body. To me, that's just common sense.
  13. valveman

    valveman Moderator Staff Member

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    Location:
    Lubbock, Texas
    I did explain it. The more heat, the shorter the life of the motor.

    You would be better off letting the pump spin at normal speed with adequate voltage, and just valve off as much flow as you want with a ball valve or a Dole valve as LL said. The amps on the motor will drop, the fan is still spinning at optimum speed, so the motor will run cool and last.

    As for the pipe, poly pipe will stretch a little and “torque up” when you first turn on the pump. But it shouldn’t move but the one time the pump is started. After that the pipe will be held rigid and in place. Unless you have a current flow in the well, there is nothing to move the pipe around. As long as you are not starting and stopping the pump (cycling) ever few minutes or seconds, the pipe is not jumping around.

    Reducing the flow rate will of course reduce the amount of sediment the well makes. That will work the same if you bog down the motor or just valve it down to make low flow. But you need over 3 feet per second velocity to make most sediments flow straight up in water. With 1 ¼” suction line that is about 12 GPM. When you valve back the flow rate or bog down the poor motor, the sand just settles back down on the foot valve. A lot of times you will see a pump make sand when it is first turned on, and that is because there is no pressure in the line so the pump can make enough water to wash out the sand that settled in the pipe when the pump was last shut off. The problem occurs when there is enough sand settled on the foot valve to stick it closed.
  14. FrustratedinNJ

    FrustratedinNJ Member

    Messages:
    32
    Location:
    NJ
    Okay, thanks.

    So then am I correct that you're saying that heat is the problem? If that's the case, then am I also correct that reducing the heat problem by limiting the pump's running time such that it never gets very warm will prevent damage to the motor?

    Another member (DonL) said: "The motor windings could burn out because you do not reach the motor operating speed." See his post to me. He said I've doubled the current and that 120v requires bigger wire than 240v. I assume he means in the windings. That suggests to me that I might be burning the windings out even if the motor doesn't get very hot, and I certainly don't want that.

    So do you see that as a potential problem?

    Or am I okay running it this way as long as I don't let the motor get very warm?

    BTW, I fully intend to run the pump at full speed (correctly wired) whenever I need to pump some serious water, like doing a load of laundry. It seems to me that would flush out any sediment resting on top of the foot valve and thus eliminate any such problem.

    I'm not particularly concerned with any sediment problem related to slower pumping. I just don't want to burn my pump motor out -- or damage the pump bearings by running it "out of phase."
  15. FrustratedinNJ

    FrustratedinNJ Member

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    32
    Location:
    NJ
    When you say " the GPM rate of pumping that is motivating it" and "Reducing the GPM by any means is likely to affect it" I take that to mean that you're saying that I'm "sucking more sediment in" when pumping at a higher GPM rate than at a lower rate.

    Is that what you mean?

    If so, then I agree with you. If you see my post ( Today at 12:35 PM ) you'll see that I attempted to keep the foot valve away from the uncased well wall for just that reason. Centering the foot valve in the well would be ideal because it would then be the farthest from the well wall as is possible. I can't accomplish that (except by dumb luck) but I can try to keep it away from resting against the well wall via my "gizmo."

    Regardless of whether my sediment problem is caused by movement that stirs up the sediment, or by "sucking strength" when pumping at a higher rate of GPM, it seems to me that pumping at a lower rate GPM would naturally result in less sediment being sucked in. Thus I'd be pumping less sediment at the lower rate GPM.

    Which is my goal, given the current status of my well (that it's uncased at the intake point).

    Anyway, is that indeed what you meant (that I'm "sucking more sediment in" when pumping at a higher GPM rate than at a lower rate) ?
  16. valveman

    valveman Moderator Staff Member

    Messages:
    4,486
    Location:
    Lubbock, Texas
    We are telling you the same thing, “don’t do that”. “Not getting to operating speed and doubling the current” as DonL said, is what causes the heat, that as you correctly say is “burning the windings”.

    Not running for very long is the worst thing you can do. The heat that is generated at start up, plus the additional heat caused by the low voltage does not have time to dissipate, as it should. You just don’t feel the heat because it doesn’t have time to get to the surface of the motor. Motor manufacturers have a certain amount of run time required to dissipate the starting heat. Otherwise the heat stays internal until the smoke wants out, and you can never put the smoke back in.

    Just let the pump have the correct voltage and use a ball valve to throttle it back.
  17. Reach4

    Reach4 Well-Known Member

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  18. LLigetfa

    LLigetfa DIYer, not in the trades

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    Location:
    NW Ontario, Canada
    Not in the way you envision it. It is not like the head of a vacuum cleaner where proximity matters. In other words, it is not the velocity at the intake per se. The water moving from the aquifer into the bore hole carries with it, the sediment like a fast moving river carries boulders. This sediment is likely motivated above the intake and drops down the borehole.

    The flow inducer that Reach4 made mention of could be so designed to make a sand separator but that is the wrong approach unless you have a lot of borehole below the intake. Sand carried into the borehole will eventually fill it up to the intake so it is best to not motivate it in the first place which is what the dole valve would do.
  19. FrustratedinNJ

    FrustratedinNJ Member

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    Location:
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    Okay, all that makes sense to me. I was concerned that the windings might burn out even tho' I don't see any smoke and don't run it very long such that the motor doesn't get very warm to the touch. It sounds like I could nevertheless burn out the windings if I continue to run it this way, even if only for very short spurts, like 20 seconds followed by a sufficient cooling off period.

    Is it your opinion that this would eventually happen, keeping in mind that I'm not holding you to your opinion, I'm just asking?

    My next question is: what about running it wired correctly but through a rheostat? I'm thinking of the old-fashioned kind liked used on an electric hot plate or stove. One site defines it as:

    Rheostat, a device used to regulate an electric current by increasing or decreasing the resistance of the circuit. Some common uses of the rheostat are to dim lights, to control the speed of an electric motor, and to control the volume of a radio. The accompanying diagram shows a simple rheostat. Current flows into the resistance coil and from the resistance coil through the slider. When the control knob is turned, the slider moves along the coil; the amount of resistance is thus changed by varying the length of the current's path through the resistance coil.

    So it's saying that one use is "to control the speed of an electric motor." That's what I'm looking to do because I want to pump water more gently (sometimes)

    I understand that the rheostat would get hot, but wouldn't that be better for the motor than the way I'm slowing it down now?

    The cooling fan aspect of slowing it down, that you mentioned, would obviously be the same. But I wouldn't be doubling the current flow and thus wouldn't be heating the windings due to that effect.

    Correct?

    BTW, I just did a load of laundry and thus ran the pump wired normally when filling the washer. Pumped at least 40 gallons to do the load and saw the usual sediment in the water, which doesn't particularly bother me for laundry purposes.
  20. FrustratedinNJ

    FrustratedinNJ Member

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    Location:
    NJ
    I see that you edited your post today. I believe you had included a formula in your original post and I don't see it now. I had intended to Google it but now I can't since I can't recall what it was. I think the formula was in support of your assertion that cutting the voltage in half doubles the current.

    I'm not an electrician but the fact that you deleted your formula (if you did) leads me to believe it wasn't correct. Which makes me wonder if your assertion is correct. Can you give me that formula again?

    BTW, your smoke comment at the end of your post isn't helpful.

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