Question on 3-phase well pump

[Furu]

I have a three phase water pump motor in a well that has not been used for some time. Long story don't ask. When it was put in the well the individual that installed it had a problem in that it was not pumping near the capacity that it should. He made a call to his boss and was told how to fix the issue which it did. I believe he swapped two wires but do not know which ones. The wiring was left "as is" bare end after he disconnected from the 3 phase power and left.

I am getting ready to use the well/pump with 3-phase power. The wiring that comes up from the well is the standard red, black, yellow, green. Interestingly the green wire end is not stripped so he never used it initially, so obviously no ground assuming it is wired normally but I have no reason to believe that the installer wired correctly as he was not the sharpest tool in the shed.

I am not a 3-phase motor expert but my understanding is a 3-phase motor that runs backward can be reversed by switching any two of the three hot wires. (on line research) I do not know this as fact however. Since I am certain he fixed his issue of low pump flow by reversing wires this implies that the well pump was running backward and thus pumping at a low rate. The pump is a relatively high flow pump 50+ gpm.

Will a well pump work, just low flow if running backward? Seems counter-intuitive to me.
Is it true that a 3 phase motor will run backward if wired incorrectly and can be "fixed" by reversing two wires?
Since I am getting ready to wire it up and I have no faith that the wire color coding is to standard I want to figure out what to do if the standard coding doesn't work for running the pump properly.

Hope a well pump installer is on the forum or a motor/pump expert.

 

[hr3]

Not a well person but I know motors,, Just wire it up color to color and if it dosn't pump well then reverse 2 leads...If is still dosn't pump call a pump guy...

Good luck..

 

[Willl]

You've got 3 phase power coming in off the street ?

That's pretty rare for a home power supply.

 

[murphy1244]

You've got 3 phase power coming in off the street ?

That's pretty rare for a home power supply.

I don't get that either, They would charge commercial power rate wich is big bucks. But if you do have 3 phases do what post 2 said.

 

[Willl]

I'm thinking it's more likely he's got a standard single phase, 220, capacitor start pump where they have the caps in a small box mounted up top and 4 wires going down to the pump motor.

 

[dex3361]

To answer your question a 3 phase submersible pump will often flow much less GPM when running in reverse depending on the head conditions and the pump. To change the direction of a 3 phase motor just swap any 2 phase leads and try it again. How deep is the well? Are you sure it is 3 phase? As others have stated it is unusual to have a residential 3 phase service.

 

[Furu]

To answer your question a 3 phase submersible pump will often flow much less GPM when running in reverse depending on the head conditions and the pump. To change the direction of a 3 phase motor just swap any 2 phase leads and try it again. How deep is the well? Are you sure it is 3 phase? As others have stated it is unusual to have a residential 3 phase service.

Thanks for your answer and that of "hr3" both addressed the question that I asked.

From what I found on an internet search I thought that was the case but wanted someone who knew from their own background that was true.

Yes it is a 3-phase motor attached to the pump, no question on that. 300 ft well

No it is not residential and no I have never heard of residential service having 3 phase power under any normal circumstances.

 

[caver]

We have some pumps at work that will still pump reversed but not as much flow. One set of pumps will spin the impeller off if we get the rotation wrong and don't catch it. Many farms around here have three phase for irrigation pumps.

 

[Baub]

Here is a good place to ask your question. This fellow seems to know his stuff.
VoyForums: Water Well Helpline Message Board

 

[podagrower]

If you have Delta 3 phase, you need to be careful which 2 legs you swap. If there are single phase controls, and you put them on the high leg, you will be buying new controls.

 

[Stimw]

Switching any two legs on a 3 ph motor changes direction.
The shape of the impeller causes it to work better in one direction AND as stated can unscrew it from the shaft because a lot of motors have left hand threads holding it on.

 

[Cat_Driver]

Need more info. Is the pump | Power, 480/277Y - 208/120Y VAC, 3-phase

Don't just switch legs till you know what you have. If you have 480 - ONE OF YOUR LEGS is 240 and the other two legs are 120. switch two 120 legs and you still have the same problem - obviously.

A 3-Wire System

Many people think that the 3-wire system refers to a "three-phase" power system, but this isn't the case at all. The three wires refer to the three colored wires that come from larger submersible pumps. These are typically yellow, black and red wires coming from the well pump to the control box. The control box is the central wiring point for this system, and it's where the three colored wires come in, as well as where the incoming power from the pressure switch are also connected. The 3-wire system is necessary for larger pumps because these pumps require a special "start-up" process.

The red cable only gets energized temporarily until the pump comes up to speed
Then the control box switches operating power over to the black wire
The yellow wire is the "common", not to be confused with the green "ground" wire that must be connected to your main power ground connection.

The 3-wire system isn't much more complicated than the 2-wire system, but it does require that the correct wires get connected to the correct terminals inside the control box.


Some diagrams
http://greenroadfarm.com/wells.html

 

[TheGoose]

3-phase pumps/motors will run backwards and they will still pump water even running backwards. Like was stated, just reverse the leads ( any 2 ) to reverse the direction.

 

[DarkBlack]

Need more info. Is the pump | Power, 480/277Y - 208/120Y VAC, 3-phase

Don't just switch legs till you know what you have. If you have 480 - ONE OF YOUR LEGS is 240 and the other two legs are 120. switch two 120 legs and you still have the same problem - obviously.

Some diagrams
Green Road Farm ~ Submersible well pump installation & Troubleshooting

3 phase 480v wired "Y" as you show always has 277 volts on each leg to ground. I think you are confusing something else, as you mention 240v and 120v.
3 phase and "3 wire single phase are unrelated. If he really has 3 phase, he would need a special 3 phase feed, or a 3 phase generator, or a VFD.
Also pump type/design is what determins if they move water while going backwards, not wheather it's a 3-phase motor or not.

 

[caver]

If you have Delta 3 phase, you need to be careful which 2 legs you swap. If there are single phase controls, and you put them on the high leg, you will be buying new controls.

It doesn't matter. Line voltage control is not common but possible in a rural area. You use L1-L2 for your starter. 99.9% of installations today
will use a control transformer for 120V control wiring.

 

[mrmikey]

I'm thinking it's more likely he's got a standard single phase, 220, capacitor start pump where they have the caps in a small box mounted up top and 4 wires going down to the pump motor.

I'm with him, one wire common (YL), one wire for run (BLA), one for the start cap (RD) and one for ground (GR) Google Image Result for http://www.make-my-own-house.com/images/controlbox.jpg ....Mike

 

[Gator6x4]

I think the poster should find a electrician familiar with 3-phase wiring and pumps. Pumps cost money, control panels cost money, and labor to remove and install a pump is expensive. Learning on the job can get expensive fast. A fifty gallon per minute pump sounds very commercial to me. 3-phase wiring also sounds commercial to me. I don't think I would trust the installation and wiring to someone who slept in a Holiday Inn Express last night as the commercial goes.

 

[mikehaugen]

a quick but not necessarily absolute way of telling if it is in fact a 3 phase motor is to take the 3 non-ground wires (from the motor) and test continuity between them. Any of the 3 possible combinations of 2 wires should give you approximately the same resistance reading (within 10%).

 

[DarkBlack]

Had to think for a second, but yes you're right. I'm not used to back yard mechanic troubleshooting shortcut methods when it comes to 3 ph. Normally, If you have 3 ph, you have trained employees. That's why I wonder if it's 3 ph at all. I ve seen 'advice' given on this forum that decribes 240 residential, as 2 phase 120.

 

[mikehaugen]

Had to think for a second, but yes you're right. I'm not used to back yard mechanic troubleshooting shortcut methods when it comes to 3 ph. Normally, If you have 3 ph, you have trained employees. That's why I wonder if it's 3 ph at all. I ve seen 'advice' given on this forum that decribes 240 residential, as 2 phase 120.

Oddly enough, I am a trained employee. This is a quick diagnostic that I use sometimes. Easy to tell if a motor is bad, but can't tell you that a motor is good. Also is a quick way to check the wiring to the motor from a contactor.