The Benefits of Three Phase AC Pumps For Solar Water Pumping


I See Electromagnetic Fields!
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.


Flux capacitor builder
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.
Here's an update.
I used
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.
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I See Electromagnetic Fields!
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.


New Member
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,
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