I have been working on an emergency Solar backup system, but my well pump uses two phase power (240 volts) and my inverter will only do 120 volt power. Could it be possible to use two inverters, one for each 120 volt leg of the pump circuit? Also, my first inverter is a 5 kw (sustained) unit, and I don’t think that this size of pump needs that much, could I use a 1 kw inverter along with the one I already have assuming that their outputs are the same voltage etc.?
Trying to run a two phase well pump
- Thread starter myself3
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WYtreasure
It's not happy hour, I'm just like this.
Welcome to the party myself3.
I know enough to be dangerous but not heard of 2 phase power yet.
Welcome to the party myself3.
2 phase is like what am electric range runs on, 2 “ hot” legs of 120vac and one neutral leg.
WYtreasure
It's not happy hour, I'm just like this.
That sounds like 240 volts in the USA. And yep, I guess it would be 2 phase.
EDIT: 2 phases?
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Mike 134
Solar Enthusiast
Will not work using 2 inverters. As others have said it's a single phase 240V pump/circuit and be sure your new inverter/and or generator has enough additional surge capacity to start the motor.
Sorry, I got confused. You are correct.
You need an inverter that outputs 220 or 240V. It is the rare inverter that can do what you want, and expensive. There are 120V well pumps. I don't know in general if you can change the voltage on any submersible well pump. That can be done on a Jet Pump. The general rule for quality inverters is three times the watts of the pump motor for inverter watts.
And, yes, household power is single phase. What gets 120V is split phase. Industrial it is three phase. A very strange beast invented by N. Tesla.
And, yes, household power is single phase. What gets 120V is split phase. Industrial it is three phase. A very strange beast invented by N. Tesla.
You would need to have an inverter capable of synching frequency to do this.
Many manufacturers offer communicating inverters that can do this.
What brand and model is yours?
Many manufacturers offer communicating inverters that can do this.
What brand and model is yours?
WYtreasure
It's not happy hour, I'm just like this.
If I am understanding correctly, there is some discussion on the subject in this thread.
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I re-read the posts twice, I must be missing something. Do you have a 240v pump with two hots (US, split), or a European style, single phase, 240v pump? Or even easier, are you in the US, or elsewhere?
In order to do a split phase 240v with two separate inverters they have to be able to communicate and synchronize the phasing, otherwise the "timing" of the pump will be all effed up, and it probably won't function at all, it might even burn up the pump or controller. There are inverters special built for that purpose, and I'm sure that somebody who's more knowledgeable about those could chime in, but it can't be done with two random, off-the-shelf, units.
In order to do a split phase 240v with two separate inverters they have to be able to communicate and synchronize the phasing, otherwise the "timing" of the pump will be all effed up, and it probably won't function at all, it might even burn up the pump or controller. There are inverters special built for that purpose, and I'm sure that somebody who's more knowledgeable about those could chime in, but it can't be done with two random, off-the-shelf, units.
I have a well pump and booster pump with a storage tank that are on 240v. They are hardwired to breakers in a box at the pump location, and then that box is trenched to the house (50-100 ft) and is in our main breaker panel off a single breaker. Based on what you wrote, I'm assuming this is single phase? I'm clueless about electricity - hard to get into solar knowing as little as I do - lol. I have a 30a/240v receptacle and a breaker/interlock installed for generator emergency use. my current plan (for the well and fridge/freezers if the power is out beyond generator fuel) is to get a dual delta pro setup with the dual / 240v connector and run my twistlock 30a cable from it right to the breaker receptacle. Much more expensive than a DIY, but I've seen it done in a delta pro review video, and would meet my ability to keep the other circuits on and re-charge the deltas when depleted. Assuming the household is single phase, it sounds like I need to verify the delta pro connector is single phase - is that correct?
I believe the delta is 120V
I think pictures might be the easiest way to figure this out. One of the breaker panel, and one of the spec plate on the side of the pump. If I had to pick one, the plate on the pump would be the most helpful.
No worries, you are putting in the effort to learn. Everyone knew nothing about electricity at one time.
I don't think that you're going to have any option other than a DIY, or professionally installed system. Most of those off-the-shelf units aren't designed to run anything that big, there might be a few exceptions, but you're going to pay some hefty cash for them.
This is the product that they say will take you to 240v. Apparently it links the 2 inverters. I was planning to use the Nema L14-30 - right from that to my receptacle. https://us.ecoflow.com/products/double-voltage-hub-ecoflow-delta-pro
As far my current setup - beats me. All I can tell you is there are 3 breakers in my breakout box (one is trenched to an above ground pool for the pool pump (yes it gets worse
) that are 20amp breakers I think, and then there is one breaker in the main panel. I have some photos of each - I'll have to find them and attach them. For some reason I also have it in my head that the breaker in the main box is actually smaller than the total of the 3 breakers outside (we're not in an area with municipal codes, probably only county/state, and I only just discovered this last week, wondering how we never popped it or burned up anything) - the 3rd breaker outside was put in by the dude who installed the decking and trenched a line for the GFCI electrical outlets for the pool area (pump / light / plugs on deck) with it's own breaker box. I can tell you that for sure I've been in the pool when the pool pump (I think 1 hp) was running and we were refilling some water in the pool - which would definitely trigger the booster pump pretty continuously. Maybe it's a double breaker and I'm losing my mind - now I need to double check - lol
I bet he has QO double pole breakers with a single handle…
Rednecktek
Solar Wizard
The other option is to drop about $1000-$1500 on a low frequency inverter that will take in 24v DC and send out 240v Split Phase. A couple panels and batteries in the pump house with it and a transfer switch or breaker interlock and you'll be good to go. Fortunately since well pumps run for such a short time normally you don't need a lot of battery, just a lot of amperage, about 300a or so so 4x 12v LFP's in series/parallel should be fine.
Build once, use forever.
Also called Split Phase power, if you were to look at the power through an o-silly-scope the waves would be 180deg off from each other. If they're not then the motor tries to spin at the wrong times and gets really, REALLY angry, Trying to run 2 regular 120v inverters doesn't work because there isn't something in between them telling 1 wave set to scoot over to keep the waves 180deg offset. An inverter that's built to provide 240v Split-Phase has that controller built into it and keeps the waves in the right place to make the motor happy.
If it's on a 30a breaker then it's probably a really large pump and/or really deep and you'd need somewhere around 3-6Kw worth of capacity not counting surge. If you can get an amp-clamp on one of those wires and find out what the actual amperage draw is that would help narrow down the size of the unit you need.
Just like any other solar project it all needs to start with the math:
How much does the pump draw? (Inverter size)
How long does it run in a day? (Solar panel capacity)
How many days of krappy weather do you want to have in your pocket? (battery capacity)
Once you have some basic numbers then you can fine tune a system to fit that need.
As an example:
My well pump at the camp draws 11.5a @ 240v or about 3Kw with losses and such, so I'd need a 3Kw/6Kw low frequency inverter.
It runs for about 45 minutes a day all total, divided by the 3 hours of sun I'd get in winter (always plan for the worst) is 3000w / .75 hours = 2250Wh, divide 2250Wh/3 hours of sun = 750 watts of panels and controller @ 24v nominal so a 40a controller would do me fine and let me over panel a bit.
If I wanted to have 3 days in my pocket of power, then I'd take that 2250Wh/day and multiply by 3 days for 6750Wh or 281Ah of battery. Might as well round that to 300Ah of battery since that's what batteries come in.
Since most BMS's (if I were able to use LFP's) come in at 100a current limits I'd probably want to stack my batteries to provide 400a of current, and using 12v batteries on a 24v system means 8 100Ah LFP batteries in the bank.
Just as an option anyways.
Build once, use forever.
Also called Split Phase power, if you were to look at the power through an o-silly-scope the waves would be 180deg off from each other. If they're not then the motor tries to spin at the wrong times and gets really, REALLY angry, Trying to run 2 regular 120v inverters doesn't work because there isn't something in between them telling 1 wave set to scoot over to keep the waves 180deg offset. An inverter that's built to provide 240v Split-Phase has that controller built into it and keeps the waves in the right place to make the motor happy.
If it's on a 30a breaker then it's probably a really large pump and/or really deep and you'd need somewhere around 3-6Kw worth of capacity not counting surge. If you can get an amp-clamp on one of those wires and find out what the actual amperage draw is that would help narrow down the size of the unit you need.
Just like any other solar project it all needs to start with the math:
How much does the pump draw? (Inverter size)
How long does it run in a day? (Solar panel capacity)
How many days of krappy weather do you want to have in your pocket? (battery capacity)
Once you have some basic numbers then you can fine tune a system to fit that need.
As an example:
My well pump at the camp draws 11.5a @ 240v or about 3Kw with losses and such, so I'd need a 3Kw/6Kw low frequency inverter.
It runs for about 45 minutes a day all total, divided by the 3 hours of sun I'd get in winter (always plan for the worst) is 3000w / .75 hours = 2250Wh, divide 2250Wh/3 hours of sun = 750 watts of panels and controller @ 24v nominal so a 40a controller would do me fine and let me over panel a bit.
If I wanted to have 3 days in my pocket of power, then I'd take that 2250Wh/day and multiply by 3 days for 6750Wh or 281Ah of battery. Might as well round that to 300Ah of battery since that's what batteries come in.
Since most BMS's (if I were able to use LFP's) come in at 100a current limits I'd probably want to stack my batteries to provide 400a of current, and using 12v batteries on a 24v system means 8 100Ah LFP batteries in the bank.
Just as an option anyways.
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