AC waterpump with solar panels

[SunEagle]

Here is some info on Franklin: http://solar.franklin-electric.com/m...anual_6-12.pdf

A copy from page 5:

The SubDrive Solar controller is a variable speed motor drive designed to run a Franklin Electric
three-phase submersible induction motor. The SubDrive Solar provides water to remote locations by
converting high voltage, direct current from a solar array into alternating current to run a standard AC
submersible motor. When solar power is not available, the controller can automatically switch to an
alternate single-phase AC input such as a generator or inverter from battery, if available. The controller
provides fault detection, motor soft start, and speed control. The SubDrive Solar is designed to provide
these features with the plug and play ease of installation similar to a single-phase control box.

there is a little more motor info on bottom of page 22 but wouldn't copy good.

If you are going to need a 1 1/2 hp or larger sub (i know they do 3 hp also not sure about others) they are worth looking into although i have no experience with them other than a couple of classes from Franklin Reps. In their classes they made it very clear that they were standard motors (although we had to laugh becase they were 208 instead of 230) They didn't fit my customers needs much (typically cattle 5-20gpm from 10'-200' depth to water)

Oh and the lorentz is a permanent magnate motor and definitely not a typical ac motor.

Brian

It looks like that Franklin pump controller has the ability to accept DC voltage from the pv panels or AC from a generator and then converts to to 3 phase AC for the motor.

As I was saying that if you are using DC from the panels the pump will not be running at full speed until the DV voltage is high enough which it will not be early morning. So it really isn't design to run continuously all day long. It is designed to capitalize on the "useful" sunlight time frame to fill a storage tank. The tank can then provide water to the crops when the sun is not enough to directly run the pump. This may be acceptable for your application but may not provide enough water if there is minimal sunlight. Having the ability to run a generator gives you the option of pumping water even without sunlight. Another way could be the use of batteries but they are much more expensive then using a gen set.

A permanent magnate is one of the standard designs for a DC motor. The lorentz system uses that design for it's pump which can be run from a DC power source (solar pv panels) or a backup AC generator through it's pump controller.

[bwkemp]

Here is some info on Franklin: http://solar.franklin-electric.com/m...anual_6-12.pdf

A copy from page 5:

The SubDrive Solar controller is a variable speed motor drive designed to run a Franklin Electric
three-phase submersible induction motor. The SubDrive Solar provides water to remote locations by
converting high voltage, direct current from a solar array into alternating current to run a standard AC
submersible motor. When solar power is not available, the controller can automatically switch to an
alternate single-phase AC input such as a generator or inverter from battery, if available. The controller
provides fault detection, motor soft start, and speed control. The SubDrive Solar is designed to provide
these features with the plug and play ease of installation similar to a single-phase control box.

there is a little more motor info on bottom of page 22 but wouldn't copy good.

If you are going to need a 1 1/2 hp or larger sub (i know they do 3 hp also not sure about others) they are worth looking into although i have no experience with them other than a couple of classes from Franklin Reps. In their classes they made it very clear that they were standard motors (although we had to laugh becase they were 208 instead of 230) They didn't fit my customers needs much (typically cattle 5-20gpm from 10'-200' depth to water)

Oh and the lorentz is a permanent magnate motor and definitely not a typical ac motor.

Brian

[bwkemp]

I couldnt find a place to link the installation manual for a lorentz that didnt have someone elses website in it so here is a copy of the info:

system PS150C
motor power [W] 250
max. power input of PV module (Vmp)* [VDC] >17
open circuit voltage (Voc) [VDC] 50
input voltage battery [VDC] 12/24
battery low voltage disconnect [VDC] 11/22
battery restart voltage [VDC] 12/24
output 4–36VEC PWM 3-phase

The pump is a 150 centric submersible, the smallest, the bigger ones will have higher output voltage. I dont know for sure if they vary the voltage, or cycles when the speed adjusts. But it is AC, yes the panels put out DC and their box converts it. Might be why they arent the cheapest pump out there. (I have installed aprox 70 of them at work, along with aprox 20 grundfos, and regretted almost all the 30 or so robinson pumps we sold)

Their website is confusing calling them brushless DC motors though. It is a "made up" AC current not a lot different the varible speed drives do off the grid.



I havent had time to look up the Franklin to make sure i am right (but 99% sure i am)

hope this helps avoid some confusion
Brian

[SunEagle]

A common misconception of how a Variable Frequency Drive (VFD) works. Most of them will reduce the applied voltage as the frequency is reduced (keeping V/f constant). If you do not do that the lower impedance of the motor windings at lower frequency will allow the magnetic circuit to saturate and the motor will overheat and fail.

For lightly loaded motors which are started at nominal frequency you might not notice the problem at low speed as the back EMF will still limit the current, but for a hard working motor like a pump motor the problem is very real.

If you go above the nominal frequency you can either keep the voltage the same and decrease the maximum torque and power available or you can increase the voltage and frequency together to keep the rated power the same. (One problem with this is that for some applications, such as blowers, increasing the speed increases the required power as the square or cube of the speed, overloading the motor anyway.)

I do understand VFD controllers and while there is a minor voltage change to control the speed the range is no where near as big as what a DC motor control circuit can do. And yes running an AC motor at a lower Hz and RPM will cause it to heat up faster so an external cooling fan is required for some applications.

Using DC power source (solar pv) to run an AC motor has built in losses and IMO wasteful. Much better to run a DC motor from a DC power source

[inetdog]

An AC motor requires a constant voltage but can be variable speed by changing the voltage frequency.

A common misconception of how a Variable Frequency Drive (VFD) works. Most of them will reduce the applied voltage as the frequency is reduced (keeping V/f constant). If you do not do that the lower impedance of the motor windings at lower frequency will allow the magnetic circuit to saturate and the motor will overheat and fail.

For lightly loaded motors which are started at nominal frequency you might not notice the problem at low speed as the back EMF will still limit the current, but for a hard working motor like a pump motor the problem is very real.

If you go above the nominal frequency you can either keep the voltage the same and decrease the maximum torque and power available or you can increase the voltage and frequency together to keep the rated power the same. (One problem with this is that for some applications, such as blowers, increasing the speed increases the required power as the square or cube of the speed, overloading the motor anyway.)

[SunEagle]

The franklins are standard three phase motors, why they used 208 volt instead of the 230 volt that is a lot more common in the us I do not know. It takes to many panels to run them (you have to get your volts pretty high) for the shallow wells i typically install pumps in so I have not installed one yet. I have sat through a few classes on them and they are definatly a standard pump/motor other than they are 208 which is available from the grid but kind of goofy in my neck of the woods.

They are all three phase, and not the more standard in low hp (less than 5) single phase phase pumps that have control boxes with capacitors and a starting relay that cuts the power out from the red wire once the motor has got up to speed.

The three phase pumps usually have a big pump panel disconnect box that has fuses overloads and a magnetic contactor all of which is there just to disconnect the pump. The pump sees the same power leaving the panel as enters. That pump panel is replaced by the solar box from franklin.


The Lorentz pumps run off dc then the box converts it to ac to run the pump. Don't believe me look at the motor, or try to check it while running with a volt meter, only reads ac voltage not dc. The voltage varries between the different sizes of motors the bigger ones higher voltage .


Just trying to get some info out there that not all solar pumps are dc. And most are not standard ac pumps like you would already have in your well.

Brian

First off all solar panels generate DC voltage. So to run an AC motor you require an inverter to convert the DC to AC. That type of motor controller can get expensive.

If you are measuring the voltage and it varies that is what a DC motor runs off of. An AC motor requires a constant voltage but can be variable speed by changing the voltage frequency.

I did not see any specifications stating the Lorentz were AC motors. All I read was that they were DC brush-less motors. Now the Franklin seem to be AC and they use an inverter/starter control box but that motor is not a standard 3 phase motor with an armature and rotor design.

[bwkemp]

The franklins are standard three phase motors, why they used 208 volt instead of the 230 volt that is a lot more common in the us I do not know. It takes to many panels to run them (you have to get your volts pretty high) for the shallow wells i typically install pumps in so I have not installed one yet. I have sat through a few classes on them and they are definatly a standard pump/motor other than they are 208 which is available from the grid but kind of goofy in my neck of the woods.

They are all three phase, and not the more standard in low hp (less than 5) single phase phase pumps that have control boxes with capacitors and a starting relay that cuts the power out from the red wire once the motor has got up to speed.

The three phase pumps usually have a big pump panel disconnect box that has fuses overloads and a magnetic contactor all of which is there just to disconnect the pump. The pump sees the same power leaving the panel as enters. That pump panel is replaced by the solar box from franklin.


The Lorentz pumps run off dc then the box converts it to ac to run the pump. Don't believe me look at the motor, or try to check it while running with a volt meter, only reads ac voltage not dc. The voltage varries between the different sizes of motors the bigger ones higher voltage .


Just trying to get some info out there that not all solar pumps are dc. And most are not standard ac pumps like you would already have in your well.

Brian

[SunEagle]

Last I knew the Franklin only ran 208 three phase motors. Also not important to this topic but worth mentioning is that Lorentz solar motors are all three phase ac motors (low voltage that won't run off the grid without a special box).

I have yet to see a controller that would run a single phase ac motor. Not saying they don't exist.

Brian

You may be correct. A small DC motor can provide more torque then a small single phase AC motor so there may not be a good application for that AC motor until you need more horsepower and then it changes to a 3 phase.

Still those 3 phase Franklin motors have just about nothing similar to a standard 3 phase AC motor including the "control" box.

Maybe I missed it but all the motors for the Lorentz solar pumps are DC. They have the ability to use an AC source but the control box converts that to DC to run the motor.

[bwkemp]

Last I knew the Franklin only ran 208 three phase motors. Also not important to this topic but worth mentioning is that Lorentz solar motors are all three phase ac motors (low voltage that won't run off the grid without a special box).

I have yet to see a controller that would run a single phase ac motor. Not saying they don't exist.

Brian

[SunEagle]

If anybody could help me how to calculate solarpanels require for each hp?

It will depend on the type of pump and controller. If you are going to use one of those Franklin pumps that Texas Wellman mentioned, they provide you with directions on how much panel wattage you will need based on your water flow and well depth.

If you are using a different pump is must be similar to that Franklin. You will not be able to run a "standard" 3 phase AC motor directly from solar panels.

[djhassoonew]

If anybody could help me how to calculate solarpanels require for each hp?

[djhassoonew]

How much water can it pump during those 6/7hours?

It will start slow, then peak around noon and then slow down again even if perfect sunlight.

I agree with you... But we are using it in desert and it fullfil requirement for daytime.

This way lot of money can be saved because we don't have to change batteries after few years.

Solarpanels can go for longterm.

[SunEagle]

I just confirmed now from the person who fixed it.
Waterpump is 7.5Hp

Solarpanels: 240w*40pcsand inverter/controller is 11kw.

It run 6/7hours in daytime

How much water can it pump during those 6/7hours?

It will start slow, then peak around noon and then slow down again even if perfect sunlight.

[djhassoonew]

I just confirmed now from the person who fixed it.
Waterpump is 7.5Hp

Solarpanels: 240w*40pcsand inverter/controller is 11kw.

It run 6/7hours in daytime

[SunEagle]

Waterpump was 3.5HPand they used 250w panels 40pcs with 7.5kw waterpump controller/inverter.

It runs 6/7 hours in daylight.

But will not run continuous if you get any clouds.

That is what we are trying to tell you that you can't keep that pump running at a constant speed should clouds come over or as the sun starts to set. The pump will either slow down and stop.

Without a constant power supply from a generator or battery you won't run that pump all day.