diy solar

diy solar

The Benefits of Three Phase AC Pumps For Solar Water Pumping

I wish ! 423 feet max.

Perhaps there are other designs elsewhere. I heard about these before, finally found a product listing.
These pumps appear to just have a gear drive and vertical shaft, no counter balance. Maybe one could be added?
As shown, appears the motor has to lift dead weight of shaft and water column, which requires torque way above what the average flow/lift would.

Another style looks like an oil derrick, so cable converts motion to vertical and counter weights can be added. Maybe there is a source somewhere.

With smallest cylinder and 2 HP, this says 473' lift 117 gallon per hour. That's 900 gallons in an 8-hour day, but a household without irrigation could get by with much less. Being fixed displacement, if counterbalanced a smaller motor geared slower should work, or greater depth (within pressure limits of pump seals.)

Ideally, pump would run at variable speed depending on available solar power. With fixed displacement rather than turbine pump that should be possible.
 
Yes, 10000TLUS said "IGBT error", not sure what state it had been in.
5000US, when it checked line voltage before reconnecting, said something like relay error. Turning off VFD didn't fix, but power cycling PV input did. I think it fed OK with VFD on, but had the problem connecting.

Maybe yet another inductor on input of VFD would help? Slight improvement in PF and waveform but not ideal.

What we want is a front-end that follows AC voltage sine wave and synthesizes sine wave current to charge the capacitors. That does exist, but don't know of an add-on unit.
Well.....
Here's an update.
I used https://ebay.us/cHQj6Y
Short answer , so far so good. Long answer below.

This is all being set up and tested in my shop before taking it out into the desert.

Solar setup:
2 x Sma si 6048 for 220 split ph
1 Sma Sb 7.7
1 Sma tu6000us
2 16s 280ah lifepo4 batts parallel to 1.25x.375 buss bar.
Batt to bus 2/0 copper welding wire
Buss to Si6048 3/0
Rec bms 1 master 6 slaves
1 array trina 250w 12 in series
1 array trina 250w 6 in series


Now I want to test this all out and see if I can run the 3hp well pump. Pump will be at 1030 feet. Bottom 100 feet is number 4 copper well wire. That's 40 submerged and 60 feet above the water level. The balance is 900 feet of number 2 aluminum direct burial wet environment wire.

For a test so far.......
Hooked up the vfd to the Power produce by the inverters. Set ramp for 50 to 60hz over 4 sec. Fired it up , all good no issues.
Ran 50 foot of #10 extension cord up to machine shop and wired it into the 3ph supply. Turned of vfd and then tried a massive 5hp surface grinder. Nope to much surge. It has a mag starter so it's not used in the rest of testing.

Reset vfd. Turned on 3hp turret lathe , the initiated vfd. Ramps up perfect. No faults on inverters.

Turned everything off. Though , go for broke. Turned on 3hp lathe , 1.1hp mini mill , and last but not least , the 2hp Bridgeport mill.
Hit the vfd and crossed my fingers . All ramped up , no faults , and only had amp clamp on one leg. 48amps max inrush.

So far so good. I used the 50 foot cord forb2 reasoned. I had it , and thinking with a bunch of line loss , maybe it would stall.

Next test will be same setup , except through the 100 feet of copper and 1000 feet of aluminum.

If will be a few days to do it , but I have Hope's. Then we will see if I need the reactor.
Greg
 
Last edited:
I think reactor may also be recommended when long run to motor, reduce voltage spikes from high frequency edges?

With a VFD running, if an inverter that has been disconnected tries to connect, that's one situation where mine got upset.
Grid failure was one where Sunny Boy disconnected and Sunny Island picked up the load. When Sunny Boy came back it had a problem.
Ungraceful shutdown of generator might do the same thing. If scheduled by Sunny Island, does it pick up the load then lift relay, then cool-down generator?
Sunrise with VFD running would be a likely one for Sunny Boy to wake up. Hopefully you don't run 1000' deep well pump without sunshine.
 
Lots of potentially complex considerations. Hard to answer without looking at exact equipment specs. Can you post links to data sheets for the Franklin items? Save us the trouble of looking them up.

My first initial thought is that you will probably pay significantly more for unique items, such as a dedicated solar VFD, or unique “solar “ pump. It is probably significantly more cost effective to use a common 3-phase pump motor, driven by a common VFD. But efficiency will probably be a bit better with a DC driven VFD, because of one less conversion loss in the circuit.

At first consideration, I don’t think it would be at all foolish to pass on the special high-cost Franklin VFD box …. Calculate what lower conversion losses you would realize, and compare that saving to the added capital cost

All is complicated by the unique considerations of your install, such as the length and convenience of wire runs, and proximity of panels and inverter to where you plan to install the VFD.

What is this about a 3 HP motor not “requiring a surge” for starting? Can you post a link? Is that a feature of the motor, or the drive? As noted above, no 3-phase motor driven by a VFD needs a starting surge if the motor speed is ramped up over some seconds - easily set within the drive parameters.

4kW of panels can all potentially feed the single 100 amp charge controllers. Depends on VOC of the panels, how they are wired in series/parallel, and the charge controller specs. Again, can you post a link to the charge controller data sheet?
Hello, Johncfii

Sorry for the delay in responding to your inquiry. Spent most of the prior week and all the last weekend having our Houston house shown and sold.
Didn't realize there were so many details involved, I thought you just showed-up at the ex-wife's attorney's office and signed it over to her.

The Franklin VFD controller included with their "sub-Solar" package has a $1398.00 price tag, a different paradigm from the Hitachi and other VFD's shown on your linked page to Wolf Automation. It may be a nice item, but I bet I could make do with a Hitachi or comparable controller.
Heck, I could buy a backup VFD and still be in the black.

The inverter/charge controller is shown here:
It has an 120 amp solar charger, (my poor recollection) and a 100 amp AC connection. Generator input? It weighs 210 lbs. w/ two massive transformers, is rated for 36Kv surge for 5 seconds.
When I mentioned "lack of surge" for the pump driver, I was meaning to say, "lack of surge with the VFD drive", but zero proofreading caught up with me on that one.
I believe the direction I'm going to try and go is another Franklin driver, this one 1-1/2 hp as my current one, but in a 3 phase configuration combined with a VFD controller, probably Hitachi. Mate that up to a new Franklin pump, I reckon the current 3 wire down-hole setup should be re-usable as long as it passes inspection.
The reason I'm going to replace in-kind is to keep my pump guy happy, I suspect he'll be unhappy if I spec out a Grundfos. Besides, this Franklin rig has been rockin' for over 15 trouble-free years.
One burning question: If I segregate my PV's and batteries into 4 different 12 volt groups, do I use a combiner box or boxes to re-join them into a 48 volt configuration? I assume that would be downstream of the batteries, but obviously upstream of the inverter's pair of 48 volt input lugs.
Should I have used 48 volt components instead?

As always, much respect for you wizards willing to assist we the unwashed masses....

The best,
-Guido
 
Last edited:
The first photo below is the output waveform from my Outback VFX3624 inverters when not powering a VFD.

The second photo is the waveform of input power being supplied to the VFD from the Outback inverters. While the audio frequency ringing imposed on the waveform has never caused any problems that I have detected, I’ve ordered a suitable reactor that might block the ringing from being fed back into my inverter and distribution system.
maybe try a AC line noise filter on that right at the ac input to the vfd.
the caps in the filter will send the high frequency noise to ground and the inductors will help filter it out while the clean 60hz will pass.
On factory equipment I have seen any trash in the incoming AC damage unprotected FVD's... I replaced a few at one factory until someone spotted a wall breaker that was arcing... after that no more dead vfd controllers ( brand was REO ) .
here is the pic of the breaker.
Old-Sparky-Breaker-gif-turlock-ca-- (1).gif
 
I sell "non solar" pumps in the north of Mozambique. All pumps have to be imported here. Obviously there are many types with different Q (discharge) - H (pressure) characteristics. I am interested in getting in to selling "solar pumps" as well. I thought one way to get around the stock issue is using a "solar inverter" which sounds a lot like the VFD's mentioned here - it just also has a DC input in addition to working as a VFD. A "(MPPT) solar inverter" can be used with an ordinary AC pump within range (kW/HP) and "type": 230 or 380 VAC, referred to here as single or three phase. They can be cheap (less that USD 100 for up 1.5 kW). But they require high DC voltage input, ideally 360VDC I think. Enter the "DC Voltage booster". It all seems to work fine, but compared to a straight forward "solar pump" (many of which also convert DC to three phase AC) the setup seems less efficient (less water for the same amount of PV panels). Does that sound right ? So far I've only tried small (up to 1 HP), 230 V pumps (I needed the DC voltage booster - presumably adding energy losses). Apparently 3 phase works better. How much better ?
 
Solar inverters, if that means typically battery type and sometimes batteries optional meant to power loads, are single-frequency not variable. So unlike VFD, they won't ramp up motor speed. They will be expected to deliver locked rotor amps or about 5x running amps for a fraction of a second. If that exceeds their surge rating, they shut off.

I understand 3-phase motors draw a high surge current just like split-phase motors, but have better starting torque. So they could start and reach speed in less time, a shorter surge.

If you can get VFD that are able to accept PV input, that would seem attractive. Maybe it varies motor speed to maximize power harvesting from PV. Ideally it accepts a wide range of PV input like other MPPT.

The ones you mention with PV input - are those just AC input VFD, with additional terminals (and maybe additional diodes) beyond the 6 diodes of a typical VFD input? I've thought about tapping into my VFD for that purpose, let PV pull voltage higher than AC rail, so it supplies power when there is sun. Just make sure it can't backfeed DC into AC grid if a diode fails! (utility transformers wouldn't like that!)

If for single-phase not 3-phase it can't vary speed much because motor won't work well. I've seen VFD for single-phase, which used starting winding as 3rd phase. That said not to run below 80% of full speed except briefly.

One guy said that well pumps shouldn't be run with a VFD because they rely on a film of water, apparently a fluid bearing, and wear is excessive until they come up to speed. Grundfos sells a PV direct well pump, may or may not have avoided that issue. I would be inclined to avoid frequent cycling of a pump started with VFD; turn it on once when tank near empty and run until full, rather than cycling every time someone uses water.
 
What I'm talking about is marketed as a solar inverter (SI), also solar pump inverter. What you're talking about I would call an ("ordinary") inverter. But my terminology might very well be off (wrong) . Output frequency is certainly variable with pump slowing down and speeding up as a bit of cloud passes by etc. Having said that, below 35Hz or so the pump struggles (as you seem to mention..) . In fact almost everything is adjustable. It also has terminals to connect level probes, pressure switches etc. It even has an external thingy that you fit with a SIM card to communicate with it. It produces three phase 230VAC (adjustable off course, it can also produce 110VAC). Most smaller pumps here are 230V single phase, with a Neutral and a Phase. The three output terminals of the SI are connected to Neutral, Phase and Capacitor (as mentioned above). It's quite possible that it doesn't work very well in the sense that that translates to loss of efficiency. That's what I'm trying to find out. The one I have is Chinese and the manufacturer has told me the 380V one works better. Grundfos and Schneider appear to have similar things and they all have three phase 380V output. I haven't looked into how they work internally. I just thought of them as a possibility to power an(y) ordinary pump with solar energy without having to use a battery. But the extra PV panels requirements are notable. Maybe that's different for the 3 phase 380VAC ones though..
 
I’ve been operating submersible well pumps for more than four decades. I’ve installed, repaired, and replaced many pumps. The reason for this post is to encourage anyone operating, or planning to operate a submersible pump on solar power, of the significant benefits of powering the pump with three phase, 230 VAC power. For a new or replacement install, it isn’t costly, and it isn’t especially complicated. You don’t need three-phase mains power. A Variable Frequency Drive generates the three phases.

The benefits:

1. NO starting surge current to overwhelm or stress your system. The variable frequency drive (VFD), that converts your 230-volt single phase power from your solar inverter to three-phase 230 VAC, is fully programable to provide a slow, linear, ramp up of motor speed. (I have mine programmed to steadily accelerate to full speed over 20 seconds). This is far superior to “soft-start” single phase motors.

2. NO high starting torque that has damaged many long down pipes, and many power leads over time.

3. Better motor efficiency. For any given HP rating, a three-phase motor is about 15% more efficient. A typical 1-1/2 HP single-phase submersible pump motor draws 10 amps at full load, which is 2300 watts at 230 VAC. A typical 1-1/2 HP three-phase motor draws 5 amps at full load, which is 1992 watts. (The formula to calculate three phase power is: 1.732 x amps x volts).

4. You will have fully variable motor speed that will allow you to reduce power draw in times of low sun energy. You can easily set your VFD to run the pump motor at 3/4 of full speed, or 1/2 of full speed. Water pumped is fairly linearly proportional to power consumed, down to about 50% of full speed. Some pump motors can even be operated with reasonable efficiency down to 25% of full speed if you are REALLY short on power reserves, and can make do with a smaller volume of water during hard times.

5. You can use smaller conductors down to the pump. Three-phase motors generally allow the use of one size smaller conductor. If your single-phase motor would require 10 ga conductors, a three-phase motor, all other things being the same, will only need 12 ga conductors. (This potential saving can be offset if your single-phase motor is 1-1/2 HP, or less, and is of the “two-wire” variety).

6. You can install your water system with a smaller, or even without, a pressure tank. This is possible because you can install a $130 pressure transducer that will send a 4-20 milliamp control signal to your VFD that varies linearly with system pressure. You program your VFD to maintain your chosen system pressure, and the pump speed will ramp up and down to maintain that constant pressure, as it reads the input from the pressure transducer. But this refinement is optional.

7. Three-phase motors cost about 10% less than single phase motors of the same HP. This is because their lower current demand allows the build with less total copper in the windings.

8. Most of these modern Variable Frequency Drives do not require a pure sine wave input. Whatever AC waveform you input is first converted to about 320 volts DC anyway. (Verify with your VFD vendor.)


The disadvantages:

1. You have to install an extra component in the form the VFD. But these are now amazingly affordable and reliable. A VFD rated for 3HP costs less than $300. I recommend selecting a drive rated for twice the HP rating of your motor. The incremental cost is very small. This increases reliability because the system runs cool, with little stress. I have both Fuji and Hitachi drives that have been in daily service for eight years with no trouble.

2. Some VFD manuals will recommend that a “line reactor” be installed at the drive output for long wire runs. Not a big deal. A $50 to $100 added cost.

3. As a DIY system, this can save you a ton of money compared to buying prepackaged system of the same components from Grundfos. But it does require some study, and some electrical understanding. If you managed to DIY your solar system, you can DIY this.

4. 1-1/2 HP is about the smallest size three-phase submersible motor available.

We have three wells on our property, all with three-phase pumps running off of VFD’s. Before my conversion to three-phase motors and VFD’s, we had to pull and replace some system component, in one well or the other, about every two years. It was always either a pump motor, a pump, cracked PVC down piping, or damaged lead wires. It was so frequent that I built an A-frame for my tractor that allows my wife and I to pull and install any pump ourselves - by running a steel cable over a pulley at the top of the A-frame, and connected to the bumper of our pickup. She would drive forward 20 feet to pull 20 feet of down-pipe up out of the well. We got to be very fast at it.

But since my conversion to three phase pump motors, we have not pulled a single pump in the eight years since. I am convinced that this is because of low starting torque, no surge current, and a pump motor than runs cooler at higher efficiency. (We do have hot well water which is not good for long component life anyway).

In the summer, when we have an excess of solar power, the domestic water pump is set to run from our solar panels during daylight hours. This is when we do our garden/lawn watering.

Here is a link to one source for the VFD’s. Note that they come in a flavor that requires 3-phase input, and a flavor that will accept single phase input:

Here is a link to a pressure transducer that can be used to replicate the Grundfos tank-less system:

These are line reactors:

Feel free to send me a direct message if you would like some help in getting past any confusion about this approach to water pumping using solar power. I’ll try to help, to the extent that work allows.
I’m glad I ran across this thread. I just replaced my well pump with a Grundfos 3hp 230 v pump currently powered by a generator. I want to power this with solar. I have been talking to RPS Solar and they have a kit for my situation (Pro Conversion Kit) includes solar panels and their control unit and everything needed for hookup. No batteries required. Any thoughts about this system? (Grundfos 16S30-24 230V 3 phase)
 
Nice post John. I'm with you on the 3 phase. I have a few with VFDs on inverters but I even like it because I can take a smaller little generator to run them out in remote pastures. I have enough that I made a quick 4 prong connector plug (not UL listed lol) so I can just take the VFD with me and plug it into a few of the different pumps I have that are the same mfg and size so I dont have to program or leave them out there. My understanding is that the DC brushless are similar in nature as they are sending 3 phases down the well from the controller (just square waves for DC?) but still getting the signal back on rotation speed so you can spin up slowly and control the speed. Not sure what really happens when I am turning down the Hz or the speed dial on one of the RPS controllers but its magic when the well only produces a few GPM and I'd rather match it then have it cycle on and off regulary... even though it is soft start, I just feel like the less I can cycle it the better. I generally don't need as much water so 3PH 1/2HPs are fine with me. There may be a few brands but I've found a good one that lets me run those 3PH pumps on solar direct or give it 220v AC and it runs just like a normal VFD. They always need more power then the little helical DC brushless ones ( I can run those with 200-400 watts) but you can get away with an affordable system still. Well, affordable not cheap. The solar+VFDs are way more, but give me multiple options and I like that. Anyways, thanks for a great post, John. The most knowledgeable on this stuff I've read yet!
 
I didn't read the thread in detail, but I've been running a Franklin fhoton system for a couple of years and so far so good. It is designed to run direct from ~4 panels. I liked the idea of having the system be it's own thing, as that is how I ran my spring for a couple of years before this well pump. The spring pump was powered through a (sunsystems?) controller box from two ancient panels, and had float switches in both the spring cistern and the main tanks that supplies gravity water to the house. It wasn't a fast pump, but the panels got plenty of sun to pump more than we could possibly use. Pump is Dankoff. Anyways, I bought the extra Franklin box that allows powering the well pump system with 120/240VAC, and honestly I never even set up the four panel array and just use an extension cord over and run it all day when I think I'm getting low. Water is about 100' deep in well, and then pumps about another 100' elevation. Soft start, draws almost exactly 1kw, 5gpm. I think it is a three phase pump.
 
Random question, but does anyone know where the Deye solar pumps are sold in the US?? About 2:2x of promo video below.
Always looking for other things. Have run Grundfos SQE for many years but price soaring as of late on their equipment. :cry:

Screenshot_20240110_084718_YouTube.jpg
 
I also run a Grundfos sq flex on 120v. Best pump made. No amp in-rush, slow ramp-up start, no weird feedback to inverter and German quality. Takes only 7a at 120v to start. I started it with a cigarette lighter inverter from my car.

 
Back
Top