Need help with project control 10 12v dc motor

Discussion in 'The Projects Forum' started by Imzautomation, Feb 15, 2013.

  1. Imzautomation

    Thread Starter New Member

    Feb 15, 2013
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    Hi experts my name is Imran and I am a mechanical engineer by profession . I am building a project where I need to control a 10 DC motors with 12 v power supply , I have plan to connect the 10 motors in parallel and supply them with 12 v ac to do adapter (the one we use for applications like phones etc ) but my question is I would like to integrate the control with MCU. Just to turn on and off my requirement is to connect mcu and motors with single power supply how should I go about it ? And please suggest which MCU to use

    Thanks
    Imran
     
  2. wayneh

    Expert

    Sep 9, 2010
    12,086
    3,024
    To re-state your request, you want to control (on/off only) 10 DC motors all powered from the same 12V DC power supply. Is that right?

    What do you mean by "control"? In other words, why not use 10 manual switches? Do you want to control the motors with a computer?

    Is the power supply rated for enough current to run all the motors at the same time? Worst case is they are all asked to start at the same instant.
     
  3. Imzautomation

    Thread Starter New Member

    Feb 15, 2013
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    I am planning to supply current from the 12V ac to dv adapter , and connect my 10 motors in parallel . I would like control the the on off with timer to delay , for example I would like my motors to start perform a 5 min cycle and stop and start after some time . And since I am a mechanical engineer I don't have quite a depth knowledge over electronics so all the suggestion will be valuable

    My main criteria is to source the MCU and motors with a mains supply , and if all the motors start at once what will be the disadvantage ?
     
  4. electron_prince

    Member

    Sep 19, 2012
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    3
    I am not very expert but i think you'd need a voltage regulator (7805). This IC will convert 12 V to 5V suitable for the MCU. and you'll need to construct a circuit with darlington pairs. maybe you'll need some power amplifiers.
    I am not sure whether your phone charger can provide such high current.
     
  5. strantor

    AAC Fanatic!

    Oct 3, 2010
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    what size are your motors? I doubt that a phone charger would oblige turning on 10 of even the smallest hobby motors at the same time.
     
  6. Imzautomation

    Thread Starter New Member

    Feb 15, 2013
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    My motors rating are 12v dc with 1000 RPM. I am looking into all suggestion as I want to achieve this project with one single power supply if the phone charger type converter is not enough what other options are available ? And how do I distribute the AC mains to mcu and motors ?
     
  7. tracecom

    AAC Fanatic!

    Apr 16, 2010
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    How much current does each one of the motors draw when running under normal load? How much current does each one of the motors draw when starting under load? Until you know those answers, there is no way to pick a power supply.
     
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  8. Imzautomation

    Thread Starter New Member

    Feb 15, 2013
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  9. thatoneguy

    AAC Fanatic!

    Feb 19, 2009
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    1 5V/1A Supply for MCU
    1 5V Coil/ with 120/240V@5A contacts Relay
    1 12V, 5A Supply for motors.

    Relay switches power on and off to the wall wart that is supplying the motor power, could also switch the 12V line that is running to all the motors @ 12V, avoiding switching the higher voltage entirely, but then a snubber would be needed to prolong relay contact life.

    This is the best I've been able to de-translate from what you are asking.
     
  10. Imzautomation

    Thread Starter New Member

    Feb 15, 2013
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    Thanks for the suggestion it looks good but my project is more like a washing machine , the proto type we are looking to build will have 10 brushes connected to 10 dc motors and like all washing machines we would like to have one power supply cable to just hook up in mains and start the device . Is it possible to supply mains voltage seperately to microcontroller and motors ? Like 5v for microcontroller and 12v for motors

    Thanks
    Imran
     
  11. Imzautomation

    Thread Starter New Member

    Feb 15, 2013
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    Any one with suggestions plz help
     
  12. BillB3857

    Senior Member

    Feb 28, 2009
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    When you say MAINS, it generally means 120VAC or 220VAC depending where you live in the world. If, on the other hand, when you refer to MAINS, you simply mean two different voltage sources, the answer is YES. One source can supply the microcontroller and the other can supply the motors. A relay with a proper coil rating and contact rating will provide the needed isolation.
     
  13. Imzautomation

    Thread Starter New Member

    Feb 15, 2013
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    Thanks a lot can you give me a schematic how to connect the mains supply to relay and then to mcu and motors , I have been going through the forum and I understand by using step down transformer I can achieve 5v for microcontroller but what about my motors ? How can I distribute seperate voltages with one AC supply I don't want to have two plugs going into wall sockets if any one can explain some example schematic it would be great
     
  14. BillB3857

    Senior Member

    Feb 28, 2009
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    A transformer with a 12VAC output feeding a bridge rectifier and filtering will give you motor power. Tapping into that DC and using a LM7805 regulator will give you the 5VDC for the processor. I you use an Arduino board, you can skip the 7805 since the Arduino has the ability to operate directly from a 12VDC source.
     
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  15. Imzautomation

    Thread Starter New Member

    Feb 15, 2013
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    Thank you for the suggestion . I am planning to use audrino board for the project I have a little confusion here as you said the audrino has in built regulator and if I connect to audrino with 12AC how should I feed the bridge rectifier then ? If you can give me a schematic or block diagram it will help me understand a lot better
     
  16. BillB3857

    Senior Member

    Feb 28, 2009
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    I didn't say feed 12VAC to the Arduino. Reread the last sentence. It clearly says 12VDC

    One of these should power the entire system for you as long as you don't run all 10 motors at full load.

    http://www.amazon.com/Replacement-Adapter-Western-Digital-Edition/dp/B005PS3Z8Q/ref=sr_1_19?ie=UTF8&qid=1361218011&sr=8-19&keywords=12v+wall+wart



     
    Last edited: Feb 18, 2013
  17. Imzautomation

    Thread Starter New Member

    Feb 15, 2013
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    Thanks bill for the suggestion I understand what you are saying but I think I am not clear in my question to I will rephrase hope I am clear now my question as you said I will feed the audrino with 12VDC wall wart and it will suply 5v to audrino good enuf my question is how will that same source should be connected to motors my project is to run all the motors to perform scrubbing like operation and I need to control on and of from MCU and for all these I need only one power source which I can input as wall wart
     
  18. BillB3857

    Senior Member

    Feb 28, 2009
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    I don't want to sound insulting, but do you know how to wire a switch and a light bulb? In your case, the switch would be a relay with its coil controlled by the Arduino. The contacts would be the switch and the motors would be the light bulb. Of course we haven't even started to discuss the program for the Arduino and to be quite honest, others would be better at offering advise for that part of your project. You would need to define what the program should do.
     
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