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Thread: Correct circuit breaker for small single phase pump motors

  1. #21
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    If someone can guide me on calculating the correct protecting circuit breaker for each of the pump circuits with one of these pump units I would appreciate it. ;-)

  2. #22
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    Franklin replied and stated the following: "The Data120 box is factory set for our borehole installations and the borehole amps required."

    They confirmed that these will not work for surface mount pumps such as these

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  3. #23
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    I will add at least 10 cents worth...

    How i would do it...taking a low budget into account...and each motor runs at around 5 amps.

    A 30 amp curve 1 or D cure breaker... taking into account the fault level at the DB....using a 4 mm cable to supply the panel.

    A control panel ...located in a position ...taking cable runs into account...and weather exposure.

    Door mounted isolator.
    manual/auto selector switch.
    4 x stop/start buttons
    1 x power on light.
    4 x run lights.
    4 x manual motor starter breakers (wired correctly for single phase circuit) OR
    "4 x 16 amp single phase D curve breakers with thermal cutouts on the motors (personally i would go with the manual motor starter)."
    4 x 9 amp AC 3 rated contactors.

    A control circuit breaker and a couple of relays for the controls.

    If there was a little left over for remote switching...or you wanted to spice up the system ...i would add an arduino with wifi capabilities...connected via an app...the way everything is going in this day and age.

  4. #24
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    Yes @ians, this is basically what I have decided on after working through the answers here and thinking about it. I am glad you are confirming my thoughts. Thanks for your detailed reply!

    Just for interest sake, I am using two raspberry PI's with expansion boards to control things. One for the irrigation control and one for the logic and remote switching of the purification system.

  5. #25
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    Quote Originally Posted by mygoggie View Post

    Just for interest sake, I am using two raspberry PI's with expansion boards to control things. One for the irrigation control and one for the logic and remote switching of the purification system.
    Silly question... why 2 Rasberry and not just an Arduino?

    What i understand of these units...the rasberry PI is a general purpose computer and the other (Arduino ) is a microcontroller?

    I would be interested to see how you control this system.

    Something else that is a consideration...control circuit voltage... i know with the large water treatment works...the control voltage is generally 24 VDC because of the PLC control.

    However on smaller plants...machines etc where there is no PLC ...just relays...level... pressure and limit switch control...12/24/110 and 230 volts is common...in fact many of the machines i work on...sometimes have 3 or 4 different control voltages.

  6. #26
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    Quote Originally Posted by ians View Post
    Silly question... why 2 Rasberry and not just an Arduino?

    What i understand of these units...the rasberry PI is a general purpose computer and the other (Arduino ) is a microcontroller?

    I would be interested to see how you control this system.

    Something else that is a consideration...control circuit voltage... i know with the large water treatment works...the control voltage is generally 24 VDC because of the PLC control.

    However on smaller plants...machines etc where there is no PLC ...just relays...level... pressure and limit switch control...12/24/110 and 230 volts is common...in fact many of the machines i work on...sometimes have 3 or 4 different control voltages.
    No question is silly.

    The one PI is used as the computing system for an Opensprinkler irrigation controller expansion board. This is 24VAC as the solenoids and the controller itself uses 24VAC. This to form part of the system as all household greywater and waste water from the purification system will go into the garden via an irrigation network.

    The second PI is used in the same way, but with another RIO (Raspberry input output) expansion board for which I have written most of the C++ code to control circuits of a research biogas digester I have designed and built. This RIO can accommodate 8 to 40VDC operating voltage. Fact is I have stock of this so why not put it to use? I can just as well change this into an Ardinio of a PLC unit if this does not work in the long run.

    Then obviously there is 230VAC in the cabinet for the pumps and the ozonator. I would like to stick to 24V and 230V to keep things simple and to a standard.

    For now I would like to see version 1 of the skid up and running which will allow me to change and improve on the design as data is gathered. No system is ever perfect and the best route is just to get it working and then refine the design until you get to a durable and lasting system. Just my design philosophy.

  7. #27
    Diamond Member Justloadit's Avatar
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    Quote Originally Posted by mygoggie View Post
    Franklin replied and stated the following: "The Data120 box is factory set for our borehole installations and the borehole amps required."

    They confirmed that these will not work for surface mount pumps such as these

    Click image for larger version. 

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ID:	7706
    I am sorry to hear that the supplier is not versed in their product range.
    The controller will work for any motor that is rated at 550W at 230V, whether it is a surface motor or a submersible, which draws at full power, no more than 5.9A, and no less than 4.9A, and whose phase angle under load remains above 68 degrees.

    The reason that it is called factory set, is that it is supposed to be a plug and play unit, to make the installation simple. We have had many challenges with customers and installation issues due to the type of end market. So much so that using the correctly sized controller for the specific motor and pump assembly warrants a long life to the motor, excluding surges and users attempting to over ride the lock out of the controller. It allows 20 starts per hour.

    If you like, I can ship you a unit so that you can try it on your motor. Just let me know.
    Victor - Knowledge is a blessing or a curse, your current circumstances make you decide!
    Solar and LED lighting solutions - www.microsolve.co.za

  8. #28
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    I was doing a forensic audit on a rainwater harvesting system a specialist contractor installed to his own standards. While working through SANS 10252-1 Water supply and drainage for buildings Part 1: Water supply installations for buildings which is the standard any water installation must comply to, I came across the requirements for pump installations. It is quite interesting and address a few of my questions.

    So I thought I would share it over here so that you guys know that there are additional requirements than SANS 10142-1 section 6.7, 6.13.2.5, 6.16.5, 7.2.4.4.

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    Last edited by mygoggie; 13-Nov-19 at 09:03 AM.

  9. #29
    Site Caretaker Dave A's Avatar
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    Just to note that there's a lot of "should" rather than "shall" in there - guidance towards good design rather than prescriptive specification.

  10. #30
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    Quote Originally Posted by Dave A View Post
    Just to note that there's a lot of "should" rather than "shall" in there - guidance towards good design rather than prescriptive specification.
    Quite correct, but it overlaps quite well what is in SANS 10142-1 and what was discussed in this thread.

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