Off-grid well pump, lowest energy consumption: variable speed vs fixed speed?

[sharpener]

5 hours ago, Hastings said:

Thank you.

 

More than happy to try and help.

 

5 hours ago, Hastings said:

The batteries are managed directly by the 48V 5kVA Victron EasySolar

 

So no separate BMS as for my LiFePO4 batteries. Otherwise your system is enticingly similar to mine as we also have a remote tank, and yr Easy Solar inverter section is electrically identical to my Multiplus II GX 5000. So I have just run through the possible settings in VE Direct but there is nothing obvious I can suggest.

 

Re-building the rainwater system that was previously installed at our house has been a long and difficult journey involving 8 ins of floodwater in the garage, a burnt out control box, a blocked pilot jet in a solenoid valve, two replacement pumps out of which I have built one working one, a new underground tank and learning quite a lot about filtration, corrosion and water chemistry into the bargain.

 

Post the results here when you are able to get back to the site for further tests!

[SteamyTea]

17 hours ago, sharpener said:

and learning quite a lot about filtration, corrosion and water chemistry into the bargain.

Start a topic in it, I find this sort of thing interesting (old Jeremy Harris had an interesting setup).

 

[sharpener]

1 hour ago, SteamyTea said:

Start a topic in it, I find this sort of thing interesting (old Jeremy Harris had an interesting setup).

 

 

Here you go @SteamyTea

 

[sharpener]

On 27/06/2024 at 15:51, sharpener said:

These heavy current pulses are something the Victron Multi inverter probably does not like, and in consequence it may not be able to power the VSD properly especially at low battery SoC. I have posted a query about this on the Victron forum, however the replies so far are about using industrial VFDs on a Multi RS Solar (which is anyway a different type of inverter not using a toroidal mains transformer) so may not be applicable to your case.

 

An update before you are next on site @Hastings in case it affects your planning.

 

There have been no further responses from the Victron forum so I have done a bit more thinking about possible harmonic filters to fix this. The VSD manufacturer does a 50A filter <EMC Filter INFILT-M501> but it is £235 plus shipping and VAT. And filters that are too big may not be effective IME.

 

I have actually got some sample toroidal choke cores which might well serve as the basis for a series filter, but annoyingly I cannot find enough design information, there is some stuff on the web e.g. this article and this one but mostly intended for big industrial applications so I have no way of knowing what component values would be correct for a small VSD.

 

So we are back to the thought of replacing the pump with a smaller, single phase one. The automatic Steelpumps X-AJE80B would be good, but any of the other three mentioned upthread would also do with a suitable pressure flow control. They all have a suction lift of at least 7m which should be enough even allowing for 1m head loss in the suction line.

 

As I wrote previously

 

On 23/06/2024 at 13:56, sharpener said:

The DAB Jetcom 62 is a bit better and will cope with a 9m suction head but has a somewhat higher max power consumption, 850W. The small Clarke is 800W, so the ST Jet 55-45 at 650W is the best of the three if max power consumption is the chief criterion.

 

so it all depends on whether you want to stick with Steelpumps, go for something that also has spare parts availability and the best suction lift (DAB), for the lowest power consumption but not repairable (ST) or for the really cheap and cheerful option (small Clarke). Given the price of the Steelpumps option and that the rest are quite close I think my favourite would be the DAB62 e.g. from here, I see they also stock the Clarke controller which I have found works fine.

 

HTH. Do let us know how the existing pump performs on a mains 3-phase supply if you are able to test it.

 

 

Edited July 1 by sharpener

[sharpener]

Further thoughts following a query I posted on the IET Consultants discussion group in an idle moment. I didn't get any more pointers on input filter design but though it worth a try. One reply suggested a power factor correction capacitor might help but I am doubtful.

 

Another suggested a circuit to minimise the inrush current. But there is already a built-in soft-start facility in the VSD, what delay is it currently set to? Playing with this might buy you some more margin.

 

Did you ever check that the motor is the 230V 3ph variant not the 400V?

 

There is also a note in the manual about letting the motor run at full speed for at least 60 secs to calibrate the drive.

 

If as I read elsethread you have an issue with acidic water then you might want to consider a plastic or stainless steel body for the pump not cast iron. There is a "polymer" version of the DAB pump, the JETCOM 62 but it doesn't seem to be readily available in the UK. So maybe s/s after all.

[Hastings]

Tested the pump and controller on a neighbour's house single-phase mains supply yesterday and there was only a very a small improvement in maximum static pressure achievable: 2.0 bar, instead of 1.8 bar I get at my house. 

 

I was not able to measure the power drawn but it appeared to get up to pressure faster and without reaching full rpm.

 

What was interesting was that when I first tried the test I did not include the pressure vessel in the output and the pump could only achieve 1.2 bar.

[JohnMo]

21 minutes ago, Hastings said:

Tested the pump and controller on a neighbour's house single-phase mains supply yesterday and there was only a very a small improvement in maximum static pressure achievable: 2.0 bar, instead of 1.8 bar I get at my house. 

 

I was not able to measure the power drawn but it appeared to get up to pressure faster and without reaching full rpm.

 

What was interesting was that when I first tried the test I did not include the pressure vessel in the output and the pump could only achieve 1.2 bar.

Pump run on pressure and volumetric flow curve. The more flow the lower the head developed. If you are running out of an unrestricted pipe it will never develop much head.

 

So for example the Jet 62, produces around 16m head (approx 1.6 bar) at full flow and 40m head or 4 bar against a closed discharge.

 

[Hastings]

@JohnMo I am sorry but I don't understand your point.

[Hastings]

Can anyone please confirm from the label that my pump is indeed the 3-phase version of the pump (and not the single phase version)?

 

I am guessing that the "Vc 450" means it is?

[JohnMo]

56 minutes ago, Hastings said:

@JohnMo I am sorry but I don't understand your point.

You made a point that on the first run you only made 1.2 and then added a pressure vessel and then got 2 bar. You seemed surprised, so was only commenting why it was the case and so other reader that have no clue about pump curves could follow. Also suspect looking at the pump curve for your pump you were measuring dynamic pressure not static. Or running at slow speed.

 

3 hours ago, Hastings said:

What was interesting was that when I first tried the test I did not include the pressure vessel in the output and the pump could only achieve 1.2 bar.

 

[sharpener]

 

2 hours ago, Hastings said:

Can anyone please confirm from the label that my pump is indeed the 3-phase version of the pump (and not the single phase version)?

 

Hi again @Hastings. The X-JE120BT does have a three-phase motor according to the FAQs here and this catalogue page, I think the T is the Italian for Trifasi. The fact that the space on the rating plate for capacitor size is blank is consistent with that bc it will not have a capacitor (but not conclusive, the Amps space is blank too). I am not sure what the Vc is, perhaps the voltage rating of the capacitor when one is fitted (single phase models only).

 

What colour wires does it have? I would expect a 3-phase motor to have 4 cores, viz 3 phases and one earth. If you have a multimeter and it is not damaged you should get the same resistance reading between any two of its phase wires (three identical readings in all).

 

I think the "230" on the rating plate confirms it is the T230 model which has the correct windings for a continental delta-connected 3-phase supply suitable for the VFD (see my queston upthread). So do not connect it to a UK star-connected 415V 3-phase supply or you will burn it out.

 

5 hours ago, Hastings said:

Tested the pump and controller on a neighbour's house single-phase mains supply yesterday and there was only a very a small improvement in maximum static pressure achievable: 2.0 bar, instead of 1.8 bar I get at my house. 

 

4 hours ago, JohnMo said:

Pump run on pressure and volumetric flow curve. The more flow the lower the head developed. If you are running out of an unrestricted pipe it will never develop much head.

I assume from yr use of the term static pressure you have tested it against a closed tap/no flow condition (although @JohnMo seems to think not).

 

In which case

(i) the pressure seems much lower than it should be

(ii) I am surprised the pressure vessel makes much difference.

 

If the combo does not perform properly on a decent mains supply then I think this at least partly exonerates your battery inverter system and calls into question the bench tests that your supplier has carried out.

 

Did you get it from a distributor? Maybe it is time to contact Steelpumps direct. I had a brief email exchange with their technical director about filters and he was quick to respond (though it was not ultimately the right answer):

 

Tom Parry
Technical Director
for and on behalf of
3P Technik UK Ltd - Water Management
STORMWATER TREATMENT | RAINWATER HARVESTING | PUMPS & CONTROLLERS | GARDEN TANKS

E: tomparry@3ptechnik.co.uk
T: +44 (0)1239 623506

www.3ptechnik.co.uk  ¦  www.steelpumps.co.uk  ¦  www.mac3uk.com

 

 

 

Edited July 20 by sharpener

[Hastings]

I had forgotten that the pump does indeed have 4 wires which are for 3-phase connection.

 

Is it possible that I wired it up wrong? I assume that if I had wired it wrongly then it would not run at all or run in reverse or something else other than pumping poorly.

 

Correct, I have been reporting only static pressure against a closed stop tap, not dynamic pressure. I am also baffled as to why adding the pressure vessel (and a little more piping) resulted in a better static pressure result.

 

I noticed, only now, from the manufacturer's data sheet power curve that power consumption is a pretty constant 1.2kW at all flow rates. That is a surprise (and a disappointment) but at least it indicates that the pump is behaving normally in that regard and not necessarily 'struggling' as I had assumed.

 

I bought the pump from 3PTechnik and have had much correspondence with Tom and his colleague who carried out the testing.

Edited July 21 by Hastings
grammatical error

[Hastings]

Mine is the 120 of the 3 available pump versions shown.

[SteamyTea]

20 minutes ago, Hastings said:

power consumption is a pretty constant 1.2kW at all flow rates.

Why would it be different.

Power is just energy per unit time, so moving 10lt in 10s is the same as moving 100lt in 100s, or a litre per second.

It will get a bit wobbly at the extremes as the pump impeller will allow some bypassing as pressure varies (equivalent bemf).

[dpmiller]

1 hour ago, Hastings said:

Mine is the 120 of the 3 available pump versions shown.

 

that doesn't look like variable speed to me. Does the pump have some kind of pressure-control/ bypass valve internally?

[sharpener]

53 minutes ago, dpmiller said:

that doesn't look like variable speed to me. Does the pump have some kind of pressure-control/ bypass valve internally?

 

I think that is the power consumption of the pump on its own, not the pump/VFD combo. To first order, the flow rate will go down as the delivery head increases, as @SteamyTea implies the power into the water is the product of the two so might well remain relatively constant.

 

Hydraulic output is delivery head in m * 9.81 * flow rate in l/s. Maximum output power will be at about half max flow rate, e.g. for the DAB 102 pictured above 3.5 * 9.81 * 0.6 so about 200W, these small jet pumps are not very efficient (you would not use them on an industrial scale or at Dinowig) and most of the rest is motor and impeller parasitic (drag) losses which are constant and independent of flow rate.

 

2 hours ago, Hastings said:

Is it possible that I wired it up wrong? I assume that if I had wired it wrongly then it would not run at all or run in reverse or something else other than pumping poorly.

 

Doubtful, you do not say the colours but I would certainly expect the earth to be green/yellow. Phase wires might be all brown (possibly numbered 1,2,3) or brown, grey, black, or something else.

Have you disconnected the motor from the VFD and reconnected it? It is possible you have got two wires swapped and the motor is running backwards, it might still pump after a fashion even so.

 

IIRC there is something about this in the VFD instructions, failing which swap any two of the phase wires with each other leaving the third as it is, see if it goes any better.

 

2 hours ago, Hastings said:

I bought the pump from 3PTechnik and have had much correspondence with Tom and his colleague who carried out the testing.

 

Did they just test the pump or the pump/VFD combo?

 

If you have exhausted all the above it is infuriating but in the interests of having a reliable water supply in a remote off-grid location may be better to cut your losses and install a small single phase pump either from the same or a different mfr depending on how you feel about them. Tom P might even be willing to give you a discount for persistence!

 

 

Edited July 21 by sharpener

[Hastings]

1 hour ago, dpmiller said:

that doesn't look like variable speed to me. Does the pump have some kind of pressure-control/ bypass valve internally?

Ah, you are correct, thank you. My pump is a speed controlled version - has a separate box/inverter with it to control speed and  set the switching pressure - the graph I posted above must be for the pump alone.

 

29 minutes ago, sharpener said:

Have you disconnected the motor from the VFD and reconnected it? It is possible you have got two wires swapped and the motor is running backwards, it might still pump after a fashion even so.

It has been disconnected for shipping back to the supplier (the pump and controller units in separate boxes) and then back to me. Maybe they wired it differently for their tests. The wiring I have used is according to a colour diagram label on the pump body but the electrician gave me a different mapping over the phone (he didn't sound too sure and so I chose the former).

I don't recall if I checked this with Tom at 3PTechnik. Perhaps the one on the pump is for Italy 3-phase and different to UK 3-phase .

 

 

Wiring for my pump (Output:grey, brown, black green/yellow. Input 240V) within the controller:

Edited July 21 by Hastings

[sharpener]

2 minutes ago, Hastings said:

The wiring I have used is according to a colour diagram label on the pump body but the electrician gave me a different mapping over the phone

 

Can't see any colour code for the connections mentioned in the VFD instructions, sounds as though it may be arbitrary. Is there a direction arrow on the body of the motor or pump? (I appreciate it is a packaged unit so may not be possible to see which way it is rotating.)

 

Try swapping e.g. the brown and black at the terminal strip and see if it is any better. It is not likely to cause any harm for a short test run.

 

I see you can also do this in the VFD software settings but personally I would swap the wires to be more confident that the test has actually been performed.

 

[Hastings]

9 minutes ago, sharpener said:

Is there a direction arrow on the body of the motor or pump?

No

 

The installation manual for the controller says:

"Connect the output cable (ground, triple-phase, screen) to the 3-phase pump using triangle configuration 230Vac."

 

I have been studying online resources on "triangle configuration 230Vac" but am unable to interpret it.

[Hastings]

Controller manual also says to contact the manufacturer MAC3 if using with a generator and/or UPS.

[sharpener]

42 minutes ago, Hastings said:

I have been studying online resources on "triangle configuration 230Vac" but am unable to interpret it.

 

See https://en.wikipedia.org/wiki/Three-phase_electric_power#Three-wire_and_four-wire_circuits for an explanation.

 

In Italy and much of continental Europe they have 3 wires plus earth. Houses often have a 3 phase supply, which is 230V from one phase to another. There is no neutral, all three wires are live. Everyone else calls this delta after the shape of the Greek letter but the Italians seem to call this triangle.

 

In the UK we have four wire plus earth three phase connections. Single phase to the typical house is 240V between one phase and the neutral. We call this star, the US calls it Y or wye. The phase to phase voltage is 415V (which will burn out your motor).

 

Do not worry about any of this, I am convinced the motor is right for the VFD but may be running backwards. Do the test!

 

22 minutes ago, Hastings said:

Controller manual also says to contact the manufacturer MAC3 if using with a generator and/or UPS.

 

Edit: Well Tom P as their UK agent knows this is what you are doing but it doesn't sound as though he has been able to come up with a solution.

 

 

Edited July 21 by sharpener

[Hastings]

@sharpener Just to be certain, I need to swap brown-black on the 3-phase output, not the input terminal?

[sharpener]

Just now, Hastings said:

@sharpener Just to be certain, I need to swap brown-black on the 3-phase output, not the input terminal?

 

Yes swap the wires going to terminals marked V and W. Good luck!

 

[SteamyTea]

35 minutes ago, Hastings said:

have been studying online resources on "triangle configuration 230Vac" but am unable to interpret it.

Try delta.

 

[dpmiller]

As it's a matched VFD I'd expect the colours codes to be a match but it's but a moment's work to swap any two phases over and re-try.

 

it's something we see in Greater Belfast vs the rest of NI and GB, it's rare that something shipped from GB works in Belfast without swapping two wires...