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#185298 - 03/09/09 12:32 AM 3 phase well pump  
schenimann  Offline
Member
Joined: Feb 2008
Posts: 193
Western North Carolina
A friend is putting in a 3 phase submersible pump. His well is 720ft deep with the pump at about 700 ft. They are concerned about the torque of a large single phase pump twisting the pipe too much. It is only about a 70 foot run to the power source. He only has single phase power, so I assume there is a converter box somewhere. Is it at the well head or at the breaker. He is getting his pump this week so I should know more then, but I am just trying to get ahead and get a little info about previous experience.


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#185299 - 03/09/09 12:56 AM Re: 3 phase well pump [Re: schenimann]  
renosteinke  Offline
Cat Servant
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Joined: Jan 2005
Posts: 5,316
Blue Collar Country
Such pumps are usually integral parts of the well casing (pipe). A million mad horses couldn't shake them loose.

Otherwise, get a three-phase pump and feed it through a frequency drive. This will provide a 'soft start' feature.


#185300 - 03/09/09 01:11 AM Re: 3 phase well pump [Re: renosteinke]  
frenchelectrican  Offline
Member
Joined: Feb 2003
Posts: 939
Wi/ Paris France { France for ...
Most well I useally run into most will have a " toqure arrester " and with 3 pump you can invest a soft start or VFD so you can able ramp up without putting in the stress on the pipes.

How big the pump it is ?

Merci,Marc


Pas de problme,il marche n'est-ce pas?"(No problem, it works doesn't it?)


#185302 - 03/09/09 03:49 AM Re: 3 phase well pump [Re: frenchelectrican]  
leland  Offline
Member
Joined: Aug 2007
Posts: 853
Lowell area, Ma. USA
Originally Posted by frenchelectrican
Most well I useally run into most will have a " toqure arrester " and with 3 pump you can invest a soft start or VFD so you can able ramp up without putting in the stress on the pipes.

How big the pump it is ?

Merci,Marc


I'll 2nd the question. how big a pump? and what is it for?


#185305 - 03/09/09 04:43 AM Re: 3 phase well pump [Re: leland]  
jraef  Offline
Member
Joined: Jul 2004
Posts: 99
San francisco, CA, USA
Just to clarify, the starting torque of an AC motor is generally the same regardless of being 3 phase or single phase. The only thing that would make a difference in using 3 phase is if you use a VFD as a phase converter. But 700 feet is a long distance for a VFD run, so make sure your motor and VFD will not have issues with that. You may need what is called a Long Line Filter or at the very least, a reactor on the output.


JRaef

#185306 - 03/09/09 09:27 AM Re: 3 phase well pump [Re: jraef]  
schenimann  Offline
Member
Joined: Feb 2008
Posts: 193
Western North Carolina
It's going to be a 3hp pump. It will be his primary water supply for his house and his livestock. The county is actually helping with the cost so that he can get his animals out of and fence off the creek.


#185309 - 03/09/09 01:22 PM Re: 3 phase well pump [Re: schenimann]  
renosteinke  Offline
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Joined: Jan 2005
Posts: 5,316
Blue Collar Country
If it's a three phase pump with a single phase supply, you're pretty much required to use a VFD ... problem solved.


#185310 - 03/09/09 01:54 PM Re: 3 phase well pump [Re: renosteinke]  
gfretwell  Offline


Member
Joined: Jul 2004
Posts: 9,080
Estero,Fl,usa
Why is he using a 3p pump? How much water can a cow drink?


Greg Fretwell

#185312 - 03/09/09 02:21 PM Re: 3 phase well pump [Re: gfretwell]  
renosteinke  Offline
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Joined: Jan 2005
Posts: 5,316
Blue Collar Country
Greg, 700 ft. is a pretty good amount of head. I suspect a single phase motor is both a lot more expensive, as well as considerably larger in size.

Incidentally ... wells are the one place I find the corner-grounded delta service.


#185317 - 03/09/09 07:39 PM Re: 3 phase well pump [Re: renosteinke]  
LarryC  Offline
Member
Joined: Jul 2004
Posts: 783
Winchester, NH, US
How do you deal with the excellent ground rod you just installed, with respect to lightning strikes? When you bond the power system to the well casing, you just made the rest of your electrical system very attractive to lightning.

Larry C


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