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  • #31
    Originally posted by bwkemp View Post
    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.

    Comment


    • #32
      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

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      • #33
        Originally posted by bwkemp View Post
        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.

        Comment


        • #34
          Originally posted by SunEagle View Post
          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.)
          Last edited by inetdog; 05-21-2015, 03:30 PM.
          SunnyBoy 3000 US, 18 BP Solar 175B panels.

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          • #35
            Originally posted by inetdog View Post
            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

            Comment


            • #36
              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

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              • #37
                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

                Comment


                • #38
                  Originally posted by bwkemp View Post
                  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.

                  Comment


                  • #39
                    Yes the pumps do start slow in the morning and then speed up, it depends on how many watts they need as to how long it takes to get to full speed or if they ever even do. Yes you have to have a supply, the few we have running houses either pump into a supply tank on a hill or fill a supply tank at the house and then have a booster pump from the grid that pressurized the house.

                    I would not recommend one for a house unless running power to the well is not a good option due to cost (the few we have are 3-4 miles from the house so wires are expensive).

                    The majority of the pumps we put in pump more than the windmills they were replacing by far.

                    As panels are getting cheaper they are getting a lot better about how much you can pump and how deep for a reasonable cost.

                    I agree that batteries charged by solar are not a good option at all for most pumping applications. We have set up a couple that you unplug the solar panels and plug into a couple of batteries that you charge at home and bring with you. Works ok if you don't own a generator or don't want to have to buy the expensive generator box from Lorentz. If you are going to do it very often buy the box. A grundfos pump is worth considering since they can be plugged strait into a generator or with an automatic disconnect box that will connect it back to the panels when the gen runs out of gas. However grundfos pumps don't work for every application.



                    I guess we will have to agree to disagree if the Lorentz pumps are ac or dc. I'll still call them ac even though they are not typical ac since the voltage and cycles are not the same as the grid. But it is a three phase motor that you can reverse the direction by switching any of the two wires, your volt meter has to be on ac to read the volts, and you can use a clamp on ac amp meter to read the amps. I'll put the voltage in the same category as a variable frequency drive fed from the grid, only it may vary more since the motors are designed to take it.

                    Brian

                    Comment


                    • #40
                      Originally posted by bwkemp View Post
                      Yes the pumps do start slow in the morning and then speed up, it depends on how many watts they need as to how long it takes to get to full speed or if they ever even do. Yes you have to have a supply, the few we have running houses either pump into a supply tank on a hill or fill a supply tank at the house and then have a booster pump from the grid that pressurized the house.

                      I would not recommend one for a house unless running power to the well is not a good option due to cost (the few we have are 3-4 miles from the house so wires are expensive).

                      The majority of the pumps we put in pump more than the windmills they were replacing by far.

                      As panels are getting cheaper they are getting a lot better about how much you can pump and how deep for a reasonable cost.

                      I agree that batteries charged by solar are not a good option at all for most pumping applications. We have set up a couple that you unplug the solar panels and plug into a couple of batteries that you charge at home and bring with you. Works ok if you don't own a generator or don't want to have to buy the expensive generator box from Lorentz. If you are going to do it very often buy the box. A grundfos pump is worth considering since they can be plugged strait into a generator or with an automatic disconnect box that will connect it back to the panels when the gen runs out of gas. However grundfos pumps don't work for every application.


                      I guess we will have to agree to disagree if the Lorentz pumps are ac or dc. I'll still call them ac even though they are not typical ac since the voltage and cycles are not the same as the grid. But it is a three phase motor that you can reverse the direction by switching any of the two wires, your volt meter has to be on ac to read the volts, and you can use a clamp on ac amp meter to read the amps. I'll put the voltage in the same category as a variable frequency drive fed from the grid, only it may vary more since the motors are designed to take it.

                      Brian
                      Usually a DC motor can be reversed by switching two wires but so can an AC motor. Since I am only going by what I have read and you have hands on experience I would say I could be wrong and your are correct concerning the motor voltage.

                      Anyway it has been a learning experience for me and I thank you for providing the links and information for those pumping systems.

                      Comment


                      • #41
                        Originally posted by SunEagle View Post
                        Usually a DC motor can be reversed by switching two wires but so can an AC motor. Since I am only going by what I have read and you have hands on experience I would say I could be wrong and your are correct concerning the motor voltage.

                        Anyway it has been a learning experience for me and I thank you for providing the links and information for those pumping systems.
                        A DC motor often has two sets of windings, one set to provide the stator field and one set to provide the rotor field.
                        The difference between a multiple phase AC motor and a mulitple phase pulsed DC motor is difficult to categorize fully. A pulsed DC motor using permanent magnets has a somewhat clearer distinction.

                        Most three phase AC motors are induction types where the rotor field is created by the stator field rather than being created by a set of coils.

                        In the past the distinction was that a DC or universal motor had a commutator to change the current and field direction in synchronization with the rotor position. But solid state electronics have made the pulsed DC system practical.
                        SunnyBoy 3000 US, 18 BP Solar 175B panels.

                        Comment


                        • #42
                          Originally posted by inetdog View Post
                          A DC motor often has two sets of windings, one set to provide the stator field and one set to provide the rotor field.
                          The difference between a multiple phase AC motor and a mulitple phase pulsed DC motor is difficult to categorize fully. A pulsed DC motor using permanent magnets has a somewhat clearer distinction.

                          Most three phase AC motors are induction types where the rotor field is created by the stator field rather than being created by a set of coils.

                          In the past the distinction was that a DC or universal motor had a commutator to change the current and field direction in synchronization with the rotor position. But solid state electronics have made the pulsed DC system practical.
                          When I worked in the shingle business the web machines were hundreds of feet long with DC drives at specific locations to move the fiberglass web through the process of making an asphalt shingles. We used "field weakening" controls to adjust the motor speed of each drive. The original DC source was a motor generator. Later on we switched to electronic DC drives made by Reliance.

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                          • #43
                            It can be done with a dc to ac inverter!

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                            • #44
                              http://www.schneider-electric.com/en...umping-system/

                              WWW

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