Limiting Flow on AC voltage - Grundfos 11 SQF 2 pump

Hello,
I currently have a Grundfos 11SQF2 pump that I need to limit the RPMs on. Static water height is ~145'. When my storage gets behind and I need to catch up, I try to run a generator on the AC input of the IO101 module. Problem is, the pump pumps more water than my well's recharge rate and the pump begins to draw air.
There are two ideas that I have thought of to limit the pump speed.
1.) Utilize a 8.4A minimum DC power supply to convert 110VAC to ~48VDC and at that condition, the pump will pump ~8.5 gpm. I am afraid if I try to utilize a power supply smaller than 8.4A, the pump will attempt to draw more current than the power supply is rated for and go into an over current shutdown?
Here is the power supply that I had in mind. Problem with this idea is that I don't think that my well will keep up with 8.5gpm.
https://www.automationdirect.com/adc/shopping/catalog/power_products_(electrical)/dc_power_supplies/5vdc,_12vdc,_48vdc,_din_rail_mount/psh-48-480
2.) My other idea is to utilize a DC drive (VFD) to provide DC power to the CU 200. I have been told that the SQF pump has an internal VFD and that I cannot supply DC power via a VFD to the CU200 in lieu of the solar panels. I don't understand why this wouldn't work. Could someone please explain why this DC drive would not work to limit the current draw/speed of my SQF pump.
Here is the DC drive that I had in mind:
https://www.automationdirect.com/adc/shopping/catalog/drives/dc_drives/high_voltage_(>_50v)_enclosed/gsd5-240-10n4
I really hope to do this without a re-circulation line dumping water back in the well. Any input or advise on slowing the SQF down utilizing an AC input would be very much appreciated.
Thanks!
I currently have a Grundfos 11SQF2 pump that I need to limit the RPMs on. Static water height is ~145'. When my storage gets behind and I need to catch up, I try to run a generator on the AC input of the IO101 module. Problem is, the pump pumps more water than my well's recharge rate and the pump begins to draw air.
There are two ideas that I have thought of to limit the pump speed.
1.) Utilize a 8.4A minimum DC power supply to convert 110VAC to ~48VDC and at that condition, the pump will pump ~8.5 gpm. I am afraid if I try to utilize a power supply smaller than 8.4A, the pump will attempt to draw more current than the power supply is rated for and go into an over current shutdown?
Here is the power supply that I had in mind. Problem with this idea is that I don't think that my well will keep up with 8.5gpm.
https://www.automationdirect.com/adc/shopping/catalog/power_products_(electrical)/dc_power_supplies/5vdc,_12vdc,_48vdc,_din_rail_mount/psh-48-480
2.) My other idea is to utilize a DC drive (VFD) to provide DC power to the CU 200. I have been told that the SQF pump has an internal VFD and that I cannot supply DC power via a VFD to the CU200 in lieu of the solar panels. I don't understand why this wouldn't work. Could someone please explain why this DC drive would not work to limit the current draw/speed of my SQF pump.
Here is the DC drive that I had in mind:
https://www.automationdirect.com/adc/shopping/catalog/drives/dc_drives/high_voltage_(>_50v)_enclosed/gsd5-240-10n4
I really hope to do this without a re-circulation line dumping water back in the well. Any input or advise on slowing the SQF down utilizing an AC input would be very much appreciated.
Thanks!
Comments
|| Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
|| VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A
solar: http://tinyurl.com/LMR-Solar
gen: http://tinyurl.com/LMR-Lister ,
If 48V works, would 36V or 24v also work ??
|| Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
|| VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A
solar: http://tinyurl.com/LMR-Solar
gen: http://tinyurl.com/LMR-Lister ,
Second system 1890W 3 × 300W No name brand poly, 3×330 Sunsolar Poly panels, Morningstar TS 60 PWM controller, no name 2000W inverter 400Ah LFP 24V nominal battery with Daly BMS, used for water pumping and day time air conditioning.
5Kw Yanmar clone single cylinder air cooled diesel generator for rare emergency charging and welding.
I am available for custom hardware/firmware development
Mike,
The pump's rated current is only 8.4A so, I wouldn't burn up a 10A power supply since the pump is unable to exceed the current draw rating? I would just run full speed at whatever voltage is being supplied? Would this thinking be correct? I will look into the Variac transformer that you mentioned. I am not familiar with this product. 36VDC would work, but not 24VDC. 30VDC is listed as the minimum supply voltage on the pump specs. Ideally, a 30VDC power supply would be best as the pump would run slower at 30VDC, 8.4A instead of 48VDC, 8.4A. A 30VDC power supply just does not look to be readily available like that of a 48VDC power supply.
Pump specs: https://product-selection.grundfos.com/product-detail.catalogue.product families.sqflex.html?from_suid=15470511055940040350568669013986&pumpsystemid=492170801&qcid=465390758
Mcgivor,
Using a water level controller/switch would not work so well for me as the storage tank that I am pumping into is 20' in diameter. It requires hundreds of gallons to raise the water level only an inch or two. When I hook my generator up and run full steam, I am pumping air in a matter of minutes. Also, the 100VAC generator is not available all of the time. I generally run the pump on PV panels. I am using the pump to water livestock in an agriculture application. When I have several days in a row of clouds, the water level gets behind. This well/pump is in a remote location on a cattle ranch. When this happens and my water storage gets behind, I would like to be able to haul my portable generator to the site, fire it up and drive off letting the generator run until it runs out of fuel to re-fill my water storage. (possibly as long as ~24 hours depending on flowrate).
Jonr,
The dry-run protection does not appear to function properly on this pump. Never has since it was new. These are high quality pumps but I have read of others having this same issue with the dry-run protection not cutting the pump off. Since the pump is over $2000, I really don't want to just let it run full steam pumping air because I know that drawing air is very hard on the mechanical components of this helical rotor, corkscrew design. I could return water to the well, just want to avoid lugging around a hose and fittings to plumb up the re-circulaiton line every time. Also, it will be running unattended, and I can't think of a good way to keep the flow correctly split between how much is going into the storage tank and how much is going back to the well. Anything messes up and the pump will be drawing air until the generator runs out of fuel or the pump burns up. Just thought that there would be a better/safer way to do it through the current/voltage source.
Thank you all so much for your replies, keep them coming!!
Clayton
Mcgivor,
Using a water level controller/switch would not work so well for me as the storage tank that I am pumping into is 20' in diameter. It requires hundreds of gallons to raise the water level only an inch or two. When I hook my generator up and run full steam, I am pumping air in a matter of minutes. Also, the 100VAC generator is not available all of the time. I generally run the pump on PV panels. I am using the pump to water livestock in an agriculture application. When I have several days in a row of clouds, the water level gets behind. This well/pump is in a remote location on a cattle ranch. When this happens and my water storage gets behind, I would like to be able to haul my portable generator to the site, fire it up and drive off letting the generator run until it runs out of fuel to re-fill my water storage. (possibly as long as ~24 hours depending on flowrate).
My idea was to use a level controller in the well itself, not the storage tank, I've used this a safeguard to protect my pump, amongst other protection, flow, pressure and time, for when I'm not present. An attempt to make something idiot proof, if there is such a thing.
Second system 1890W 3 × 300W No name brand poly, 3×330 Sunsolar Poly panels, Morningstar TS 60 PWM controller, no name 2000W inverter 400Ah LFP 24V nominal battery with Daly BMS, used for water pumping and day time air conditioning.
5Kw Yanmar clone single cylinder air cooled diesel generator for rare emergency charging and welding.
Ahh, I understand your thinking. Yes, several of the other solar control boxes that I have ran in the past have a "well float" input. However, since the Grundfos is made to have it's own "dry well sensor" (which is wired into the factory pump leads), the Grundfos CU 200 controller does not have a well float input. Any idea how to wire up a "stand alone" well float?
Aguarancher,
Lol, yeah I'm familiar with the old school ways. We do it on irrigation wells but I just hate it. It's hard on the pumps and difficult to keep adjusted to keep from pumping air. Also, have a look at the pump curve shown in this link.
https://product-selection.grundfos.com/product-detail.catalogue.product families.sqflex.html?from_suid=15470511055940040350568669013986&pumpsystemid=492170801&qcid=465390758
If I crank the gate valve down to increase the head pressure, I really don't decrease the flow much when utilizing an AC input. With an AC input, the pump is going to be running full steam. For instance, if I gate valve the flow off, I would say for comparison sake, move from the 131' head pressure curve to the 394' curve. Max potential on the 131' curve is 12.4 gpm and max potential on the 394' curve is 10.3 gpm. If I cranked the gate valve down to cut flow down to ~6gpm, I'll over pressure and trash the pump.....
Mike,
I looked into the Variac transformers. I didn't see one that fits the bill for this scenario. Problem is that my minimum AC input voltage for the pump is 90 volts. At 90VAC and 8.3A, the pump is still running at max potential (on the 131' TDH flow curve). The advantage of converting to Ac over to DC is that the pump can accept down to 30 volts DC.....
htps://offgridsolar1.com/
E-mail [email protected]
As far as I can tell, 8.4 A rating is what goes to the motor - not the input to the DC-DC converter.
It's not clear to me what will happen if you further current or voltage limit the input. Does it continue at full output down to 30V and then shut off? Or produce less output below some voltage?
In any case, this isn't a simple brushed DC motor where less voltage clearly slows it down.
I am available for custom hardware/firmware development
Only $30 to try. Let us know if it works.
Search ebay for: DC-32V10A-Switching-Power-Supply-32V-320W-LED-Lamp-Industrial-Control-Equipment
I am available for custom hardware/firmware development
If this is a new ap, make sure you have good surge protection and grounding. This controller has a history of easily being damaged.
htps://offgridsolar1.com/
E-mail [email protected]
I am available for custom hardware/firmware development
htps://offgridsolar1.com/
E-mail [email protected]
The issue I have is that when providing 120V @ 8.4A, the pump pumps more water than my well can provide. I am looking for a solution to limit the pumping rate when utilizing an AC generator. I need a method to limit current output to the pump.
I am available for custom hardware/firmware development
htps://offgridsolar1.com/
E-mail [email protected]
htps://offgridsolar1.com/
E-mail [email protected]
htps://offgridsolar1.com/
E-mail [email protected]