Dc motor help

Discussion in 'General Electronics Chat' started by Richieyoung85, Sep 12, 2017.

  1. Richieyoung85

    Thread Starter New Member

    Sep 1, 2017
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    How can i reverse power on a 9v dc motor?
     
  2. AlbertHall

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    Assuming it is a brushed, permanent magnet motor, if you connect the power the other way round the motor will turn the other way.
     
  3. Richieyoung85

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    Sep 1, 2017
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    I want it to go one way then i want to be able to reverse it.
     
  4. AlbertHall

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    So you will need a switch/relay/H-bridge to reverse the power when you want to.
     
  5. MaxHeadRoom

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    A little info on the application might help, together with motor size.
    Max.
     
  6. Richieyoung85

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    What is a h-bridge? Im very new to this stuff just tinkering around.
     
  7. AlbertHall

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    How do you want to control the direction - manual switch, microcontroller, remote control, etc?
     
  8. MaxHeadRoom

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    There are SO many previous post on this subject, just here alone that a search will turn up, if you find one, then enquire if you can adapt it for what you have in mind!
    Max.
     
    shortbus likes this.
  9. Richieyoung85

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    Sep 1, 2017
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    Manuel switch for now.
     
  10. MaxHeadRoom

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    Single P.B. or dual P.B. or double pole double throw switch, Does it have to run to limits in either direction or does the manual switch control it.?
    You still haven't given any details??
    Max.
     
  11. jayanthd

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    Jul 4, 2015
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    This is the working of H-Bridge. Diagonally opposite switches will be ON at a time. If High-side and low-side switches turn ON at the same time then The +ve Power will connect to GND and results in a short circuit. If you use Mosfets for the switches then due to short circuit the Mosfets will blow.

    See simulation video.
     
  12. Richieyoung85

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    Sep 1, 2017
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    For some reason it will not letme open this file.
     
  13. MaxHeadRoom

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  14. jayanthd

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    It is Proteus file. You need Proteus to open that file. See video instead.
     
  15. MaxHeadRoom

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    With the DPDT you don't need logic or relays.
    Max.
     
  16. Richieyoung85

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    Sep 1, 2017
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  17. Richieyoung85

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    Sep 1, 2017
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    Im having a hard time figuring out wiring and what switches to use to stop when raised and then stop when lowerd again.
     
  18. jayanthd

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    I just gave an explanation of H-BRIDGE working.

    Here is the updated circuit which uses practical DPDT switch. See simulation video.

    Mention your exact requirement. Do you want to stop the motor then add a SPST switch in series with the H-BRIDGE and V+.

    Here is the project with one SPST and one DPDT switches.

    If you are making automatic gate control then it is better to use a PIC Micrcontroller for the project. It will use two end sensors, a motor and H-Bridge. When end position of the garage gate is detected then it will stop the motor.

    Additionally I can add a remote control and motor stall detection (for saftey purpose).

    I can write a code for you for free. If you are interested then provide more details about the motor. A datasheet of the motor will be helpful.

    Additionally a IR sensor will be of use. If there is anybody near the gate then it will stop motor.
     
    Last edited: Sep 13, 2017
  19. MaxHeadRoom

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    It is just a DPDT (Double pole-Double throw toggle sw ) with centre off position.
    i.e. 3 posn.
    Similar to the pic.
    If the limits, any mechanical NC/NO micro switch will work.
    [​IMG]
    Max.
     
  20. jayanthd

    Active Member

    Jul 4, 2015
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    What motor are you using ? What is its voltage and current ratings ?

    It is better to go with micrcontroller based design.

    switches current and operating voltage ratings should be 20% more than the required ratings. Choose proper switches.

    Micro switches are for end position detection. No for controlling the motor. micro switches will signal the micrcontroller about the gate reaching the limits.
     
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