Active power factor correction

[rvalente]

I'd say automotive, deep cycle batteries here are not common at all and if you could find stationary ones here they're pretty price

[TheMG]

One other thought--you mentioned that the pump ran for 15 minutes at 54Hz.  If the input to the inverter is, say 3.2kW, that is a roughly 66A load on the batteries, more than C/2.  Have you checked to see how low the battery side of the inverter is going?   That 120Ah is likely the C/20 rate, at more than C/2 you are pushing the limits there too.

That is definitely something to consider. At a discharge rate of C/2, the effective usable capacity becomes approximately half of the C/20 rating for most AGM deep cycle batteries. So about 60Ah is the most you're going to get out of a set of new, healthy, fully-charged 120Ah batteries. Less than an hour of pump run time with that setup, on brand new batteries (not accounting for input from the solar panels).

[Palmitoxico]

That helps a lot.  It is a brand new, very efficient motor, so going to a BLDC setup isn't going to help all that much.  It's interesting that they list 50Hz specs, although there doesn't seem to be any real design involved--almost any 60Hz 3-PH motor would behave similarly.  Note the 1.00 service factor at 50Hz. 

Does this motor come attached to the pump as a unit or are they two separate items that you have combined?  If the pump/motor is sold as a unit, does it have specs for flow and head pressure?

So I get 3288kVA and 2926W at full service factor load at 60Hz, not counting any VFD losses or tolerances in specs for the motor or the inverter--both of which could be rated optimistically.  Better than my earlier estimates, but still either cutting it close or just too much, depending on the loading.  The 0.6 PF of the VFD may not be helpful, but you're still at or near the limits.  The fact that reducing the VFD frequency to 54Hz extended the run time seems to back that up.

One other thought--you mentioned that the pump ran for 15 minutes at 54Hz.  If the input to the inverter is, say 3.2kW, that is a roughly 66A load on the batteries, more than C/2.  Have you checked to see how low the battery side of the inverter is going?   That 120Ah is likely the C/20 rate, at more than C/2 you are pushing the limits there too.

We bought the pump + motor in a single unit, I've attached the flow / pressure relationship for our model (now I don't remember if the model we have is the ME-AL/BR 1630 or ME-AL/BR 1630V). Captions (attachment):
Potência (cv) = Power (hp)
Estágios = Stages
Monofásico = Single-phase
Trifásico = Three-phase
Ø Sucção (pol) = Ø Suction
Ø Recalque (pol) = Ø Repression ??
Pressão máxima sem vazão (m.c.a.) = Maximum pressure without flow (water column meter)
Altura máxima de sucção (m.c.a.) = Maximum suction height (water column meter)
Ø Rotor (mm) = Ø Rotor (mm)
Altura Manométrica Total (m.c.a.) = Total manometric height (water column meter)
Vazão em m³/h válida para sucção de 0 m.c.a. = Flow in m³/h valid for a 0m water column suction

The load was split between the solar panel and the batteries at the time my father was testing, but the voltage was stable arround 47.5V running. This system will work only during the day intermittently, 40% max depth of discharge to extend the batteries' longevity.

I'd say automotive, deep cycle batteries here are not common at all and if you could find stationary ones here they're pretty price

No, we bought stationary batteries from Moura. Automotive batteries would have a poor longevity. Yes those were more expensive but not by a huge margin.

The CFW500 has a bunch of nice features, had you ever checked the motor power on the VFD to see how much do you really need?

If yours have the plug-in card you can connect to the superdrive G2 software and monitor it.

I don't think we have the model with this plug-in card.

[Palmitoxico]

One correction, we are using 4x400W solar panels, we measured a total output of 1500W at peak sun light. The total pump running time for the day should be about 3h at a reduced power (3HP is more than we need).

[NiHaoMike]

Less than an hour of pump run time with that setup, on brand new batteries (not accounting for input from the solar panels).

So in summary, either the pump is too big or the rest of the system is too small.

[rvalente]

Nice, you've got yourself nice batteries.

Check P0010, its motor power and see how much you're truly using.

About the VFD, did you filled all the motors parameters P399 and so on...

P202, V/F or VVF? The standard is V/F and it has a huge impact in current, specially at start-ups.

Did you run the auto-tuning? P408?

Have a look at Weg Pump genius technology, i'm not sure if your drive has such technology but is specifically made for reducing pumps power usage.

[Palmitoxico]

Nice, you've got yourself nice batteries.

Check P0010, its motor power and see how much you're truly using.

About the VFD, did you filled all the motors parameters P399 and so on...

P202, V/F or VVF? The standard is V/F and it has a huge impact in current, specially at start-ups.

Did you run the auto-tuning? P408?

Have a look at Weg Pump genius technology, i'm not sure if your drive has such technology but is specifically made for reducing pumps power usage.

My father has configured the VFD following a guide from WEG, I don't know what parameters he put  at the V/F ramp. I don't think our VFD supports this 'WEG Pump Genius' but I may have a closer look.

Nice to know about P0010, next time we will check it.

[bdunham7]

We bought the pump + motor in a single unit, I've attached the flow / pressure relationship for our model (now I don't remember if the model we have is the ME-AL/BR 1630 or ME-AL/BR 1630V).

Do  you know what the actual output pressure at the pump is when it is running?  Is there any significant inlet suction due to height or filtration?

[Palmitoxico]

We bought the pump + motor in a single unit, I've attached the flow / pressure relationship for our model (now I don't remember if the model we have is the ME-AL/BR 1630 or ME-AL/BR 1630V).

Do  you know what the actual output pressure at the pump is when it is running?  Is there any significant inlet suction due to height or filtration?

I'll ask my father these questions  tomorrow, but I think he measured 6 bar at the pump output.

[Doctorandus_P]

As the thing is solar powered I assume intermittent use.
A simple solution may be to adjust the settings of the 3-phase inverter.
Just run your pumps at lower rpm, but for a longer time to do the same amount of work. this reduces the strain on the 48Vdc -> 220Vac inverter.

I do not know what this would do to overall efficiency of the system though. It may get better or worse.

[Palmitoxico]

We bought the pump + motor in a single unit, I've attached the flow / pressure relationship for our model (now I don't remember if the model we have is the ME-AL/BR 1630 or ME-AL/BR 1630V).

Do  you know what the actual output pressure at the pump is when it is running?  Is there any significant inlet suction due to height or filtration?

I'll ask my father these questions  tomorrow, but I think he measured 6 bar at the pump output.

Confirmed, it is running with 6 bar at the pump ouput. The pump is placed about 1m in height from the aquifer, the filter is very coarse, so I don't think it interferes to much.

As the thing is solar powered I assume intermittent use.
A simple solution may be to adjust the settings of the 3-phase inverter.
Just run your pumps at lower rpm, but for a longer time to do the same amount of work. this reduces the strain on the 48Vdc -> 220Vac inverter.

I do not know what this would do to overall efficiency of the system though. It may get better or worse.

Yes we will run at a lower rpm to limit the power requirement.

My father contacted the manufacturer of the 48VDC -> 220VAC inverter today and the manufacturer told that the transformer temperature switch might be the problem by been too conservative. The power electronics, he said, should be fine because it was designed to handle up to 5KVA. He recommended placing the temperature sensor in a different location, so we'll try this next week probably.

As soon as we get new data I'll post here.

[bdunham7]

The power electronics, he said, should be fine because it was designed to handle up to 5KVA.

That certainly is helpful--and more in line with margins that keep things reliable.

Did you determine which model pump you have?  I looked at the flow/pressure chart and I'm hoping you don't have the 'V' model, unless you might need more pressure at another time.  Fluid pumps have a power/flow curve that varies with design, but max head pressure is not usually the highest power point--and  in your case, the maximum pump load might be somewhere in those asterisks.  Slowing it down will shift things to left.

Another thought I had was that it might be easier and safer to check the inverter input current.  You can then directly see how the various speed selections affect input power.  I'm thinking if you can stay under 60A input you'd be in good shape. 

[Palmitoxico]

Did you determine which model pump you have?  I looked at the flow/pressure chart and I'm hoping you don't have the 'V' model, unless you might need more pressure at another time.  Fluid pumps have a power/flow curve that varies with design, but max head pressure is not usually the highest power point--and  in your case, the maximum pump load might be somewhere in those asterisks.  Slowing it down will shift things to left.

Confirmed here it is the ME-AL 1630 model without the 'V' (AL stands for aluminium shaft and BR for bronze shaft).

Is too late now to change our system but I came across an interesting product, it consists of a smart solar powered VFD, no batteries required: https://www.usfull.com/wp-content/uploads/2016/11/Fullwil-solar-pumping-system.pdf
Of course, you need enough solar panels in series to provide the necessary DC voltage so the inverter can output 220VAC. From what I read, it controls the output power by changing the AC frequency, so it can do some sort of MPPT to better harness the solar panel power.

And amazingly, I can buy it locally!

[bdunham7]

Is this system an 'on demand' pump or an 'as available' system?  If you get the inverter sorted, it actually seems a pretty good setup for only 4 panels.

I'd suggest you characterize the pumping performance by measuring the actual flow at various speeds to see what is most efficient in liters per watt-hour.

[Palmitoxico]

Is this system an 'on demand' pump or an 'as available' system?  If you get the inverter sorted, it actually seems a pretty good setup for only 4 panels.

It is an 'as available' system. It pumps the aquifer water in to a reservoir for later use. It is intended to replace the previous gas powered pump (the gas pump will only be used when there isn't enough sun light to charge the batteries).

I'd suggest you characterise the pumping performance by measuring the actual flow at various speeds to see what is most efficient in liters per watt-hour.

Right, we will try measure it.

[Palmitoxico]

Hi everyone!

Just a quick update, we positioned the inverter's transformer temperature sensor in a different place as the manufacturer recommended and it has been working very well last 3 weeks. The pump is operating at 56Hz and 1.4 - 1.5 kW as showed by the VFD (parameter P0010). We couldn't measure the total flow yet (a water flow meter will be installed soon), but it seems enough for now.

I attached some pictures of the system if you are curious.

Thank you very much for all your suggestions!

[rvalente]

It is great that it have been working for 3 weeks now.

The good thing is, there are lots of room for improvements there.