is it possible to build a 240V solar system?

hmong2017 · July 2018

I have a 4HP 240V AC Well Pump. We are paying too much to irrigate our farm.
I was wondering instead of changing all of my pump system into a solar pump system, Is there a way to build a 240V Solar System to power my old well pump?

I need 240V AC not 240VDC.
I tried to look up US 240V plug power inverters, but I don't see any. Is it because it's not possible?
If it's possible. Please help create a list of what I need. Thank you.

BB. · July 2018

Here is some starting information:

Re: Working Thread for Solar Beginner Post/FAQ

Some discussions about VFD (Variable Frequency Drives)... Basically a variable frequency inverter with (typically) three phase output. Used to soft start motors (handy for 3 phase well pumps, or pumps with well head starting capacitor) and can also turn an AC motor into a variable speed motor (very handy for pumping applications).

WELL PUMP and Inverter QUESTION
Wind/solar for large scale pumping etc (out of my depth!)
could use knowledge - using Gould jet pump - transfering from 230vAC to ? DC (new link/thread 10/27/2012)
Help required to design off grid system (information on possibilities to connect "standard VFDs direct to solar panels) (new link 1/13/2013)

And from a new poster, link to solar VFD (looks interesting):

VeichiElectric said:
u really should read this article about solar pumps: http://www.veichi.org/solar-water-pump-inverter.html.
In your case I wonder if a solar PV inverter would help or not.

-Bill

1/7/2017:
Dave Angelini said:
Grundfos has been doing solar water pumping for 30 years in the Americas and over the seas

http://us.grundfos.com/about-us/news-and-press/news/Pumped-by-the-Sun.html
They have some really nice plant tours down in the Fresno area of California.

Does any of the above look "interesting"?
-Bill

jonr · July 2018

I'd start by carefully investigating the efficiency of your current system. Pump efficiency, pipe losses, reduced water usage, off-peak rates, lower GPM for more hours, etc. Then I'd look into a grid-tie system.

mike95490 · July 2018

Depending on what state and incentives currently exist, there may be some tax or rebates for installing GT solar.

Dave Angelini · July 2018

A grid tie is great. They are getting harder to get as utilities are taking the incentives away. You can do a zero export system if you only pump during the day. Been doing a few of them lately for pumping.

As the guys have said here, you need a new 3 phase pump and VFD with a good controller built for it.
There are incentives for the pump in this state so conservation is always the first step, if you come back to your thread here....

oil pan 4 · July 2018

You would at least need a variable frequency drive to start 3 phase pumps that way they can be started with out a huge start up surge.
There are a ton of off grid inverters that make 240v. The host of this forum sells a bunch of them.
You don't have to have a controller made for your well pump, the parameters and inputs that come built in with the drive are more than enough to control a pump.

2 things we need to know is how much money you have to spend.
And how much power do you use?
Maybe 3rd, how much water do you use and how deep is your well?

BB. · July 2018

The original poster is probably somewhere in the California Central Valley.

-Bill

oil pan 4 · July 2018

Calafornastand, their's the first problem.

Horsefly · July 2018

I'm a little confused. There's several responses about 3-phase, but the OP only mentioned 240V. How do we know he needs 3 phase?

If his pump is 240V 2-wire, one of the Schneider split-phase Sw or XW inverters would satisfy.

mcgivor · July 2018

A VFD which is typically a 3 phase device, it can actually be used with a single phase input to provide 3 phase output, the input could be AC or DC because the VFD is going to rectify an AC input anyway. Using a 3 phase pump is more efficient with lower start up inrush, there are of course other options like DC pumps which need less of the complexity, but may have limitations on total head, without those figures everything is hypothetical.

Dave Angelini · July 2018

Horsefly said:

I'm a little confused. There's several responses about 3-phase, but the OP only mentioned 240V. How do we know he needs 3 phase?

If his pump is 240V 2-wire, one of the Schneider split-phase Sw or XW inverters would satisfy.

We know this because they are incredibly more efficient and there are incredible rebates in this state still. They run from any voltage and by using the controller designed for the 3P pump, there is engineering in the whole system.

The best solar contractors would do this along with selling a solar system. It makes the whole system look very good on paper when the power bill comes. Too bad the OP never came back....

BB. · July 2018

Motors over ~1-2 HP and are commonly 3 phase. Both cheaper and more reliable (no starting capacitors, no "extra starting windings" that are not used once the motor is up to speed, etc.)... 3 phase drops to commercial sites is very common.

So, don't know if this well pump is 3 phase, but is a good guess that it is probably is.

-Bill

Horsefly · July 2018

I'll take your word for it Bill. I know I've seen 2-wire 230-240V soft-start pumps of 2.5HP from Grundfos. Maybe they are just the exception.

BB. · July 2018

Grundfos pump motors can be permanent magnet poly phase with an internal VFD. (Their 900 Watt submersibles are generally this,I believe).

It just depends on the what power is available and which pump motor was purchased.

3 phase with vfd motors are a pretty flexible combination.

Bill

Dave Angelini · July 2018

Horsefly said:

I'll take your word for it Bill. I know I've seen 2-wire 230-240V soft-start pumps of 2.5HP from Grundfos. Maybe they are just the exception.

Right, but have you looked what the pump is inside a grundfos? It is a three phase pump with electronics designed to run it extremely efficiently and the controls above the ground to optimize it.

If the OP ever came back, we could maybe find out what he had. Even if he had a 3P pump, adding a VFD to it might not do him much good as this needs to be designed into the system to save max energy. Just adding a VFD might get you a softer start but all of the other factors really need to be addressed for max savings of energy. Like does he really need 4HP and quite a few more.

I get grid people asking me to help them go offgrid and have solar. Since I do not want to have anything to do with utility solar hassles, and there are plenty of grid solar folks who do, I tell them, how much do you want your utility bill to be? It is then a matter of saving the energy that they are wasting. Usually it is something like this here, adding a mini split to reduce the huge load of a forced air ducted system, or replacing a pool pump with a 3P VFD drive. I bill them and no one has to go on the roof! You should see the money people are wasting.
It does take money to start something like this.

NANOcontrol · July 2018

Franklin has the line of Fhoton Solar Pump with many options that might be interesting for others who want to run without batteries.

Dave Angelini · July 2018

NANOcontrol said:

Franklin has the line of Fhoton Solar Pump with many options that might be interesting for others who want to run without batteries.

Franklin is one of the most durable pumps ever made. We had a friend who had their well fail and the pump was still good. It had a date code on it from 1978. Their 3 wire pumps have a surge but it is much lower than the 2 wire pumps.

There are quite few solar direct pumps now. The first was grundfos and there are at least 4 that come to mind.

is it possible to build a 240V solar system?

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