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Reversing Motor Direction With Relays

Discussion in 'Microcontrollers, Programming and IoT' started by x10, Jul 11, 2017.

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  1. x10

    x10

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    Jul 11, 2017
    using X10 modules to control power to 2 12V power adapters connected to motor with opposite polarity did not work. i am assuming the adapters act as huge capacitors when not powered. i am now trying to isolate power adapters with relay boards which are cheap ($0.89) like:

    http://www.ebay.com/itm/10A-1-Chann...e=STRK:MEBIDX:IT&_trksid=p2060353.m2749.l2649

    motor:

    http://www.ebay.com/itm/Reversible-...var=511517130420&_trksid=p2060353.m2749.l2649

    the relay is designed for use with arduino or similar but i am connecting simply to power adapters (5V and/or 12V) controlled by x10 modules. i am not sure how to wire power adapters to VCC, GND, IN pins. Suggestions? Thanks.
     
  2. Minder

    Minder

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    Apr 24, 2015
    Not sure how they pull that off when they say it requires 12vdc but there is a 24vdc relay on it, the input appears to require at least 14ma signla with respect to ground to operate, hard to reverse engineer it from the Pic.
    Those units will not reverse the motor.
    Why not use a logic level Mosfet from the Arduino to power the motors direct?
    M.
     
  3. x10

    x10

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    Jul 11, 2017
    Thanks for reply. I don't do arduino yet. This is an X10 project. I dont expect relay to reverse. Just isolate the power supply. Wiring 2 power adapters directly to motor doesnt seem to work.
     
  4. kellys_eye

    kellys_eye

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    Jun 25, 2010
    Looks like a 12V relay to me - the contacts are rated at 10A for 24V throughput. It also spec's a 4mA drive signal which is easily provided by an Arduino port.

    Two such boards will reverse a motor.

    Vcc and GND are required to power the control electronics. IN is the control signal.

    Having re-read your post I see what your problem is but suspect the motor back EMF to be overloading the supplies at switch-over. Does the motor come to a complete halt before reversing or are you using the power supply to 'brake' and then reverse?

    Better to use a single supply source and two relay boards to make the change over.
     
  5. x10

    x10

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    Jul 11, 2017
    Thanks for your reply. Unfortunately I dont have arduino. I want to trigger with a power adapter controlled by X10 if possible. I'm assuming a power adapter is acceptable as "signal" but not sure how to wire it. If I put 12V+ on IN and VCC with power adapter ground to GND I do not get relay to close Normally Open connectors.
     
  6. Minder

    Minder

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    Apr 24, 2015
    Misread it in haste!
    M.
     
  7. Minder

    Minder

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    Apr 24, 2015
    What are the details of the adapters? How did you hook them up?
    M
     
  8. x10

    x10

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    Jul 11, 2017
    I'm assuming you mean failed hook-up. Just pulled some spare 12VDC low amp power adapters from box and wired to motor with high-tech wire nuts. Plugged each power adapter into its own X10 control module. Turned on one and nothing happened. Turned off and turned on other one. Nothing. But if I wire them onto motor independently the motor operates in correct direction.

    I guess the problem here is that the ground operates at all times regardless of control modules so i need to isolate. I guess I assumed that ground would be open but it's not.
     
    Last edited: Jul 11, 2017
  9. Minder

    Minder

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    Apr 24, 2015
    Did you actually monitor the voltage at each motor for each condition?
    M.
     
  10. kellys_eye

    kellys_eye

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    Which X10 control module are you using and what signal is it outputting to 'drive' the motor?
     
  11. x10

    x10

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    Jul 11, 2017
    I dont have a real bench so "monitoring" was just observing whether motor ran or not. I have a meter but this tiny little project is just bouncing around on a desktop. I am hoping i just need to figure out how to attach adapters to VCC, GND, IN pins.
     
  12. x10

    x10

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    Jul 11, 2017
    I am using an X10 appliance module to power 12VDC power adapters to power motor through 2 relay boards supplying different polarity for different motor direction.

    So basically:
    Outlet AC -> X10 (AM466) -> power adapter -> relay -> motor
     
  13. kellys_eye

    kellys_eye

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    What kind of power adapters? Linear or switched mode? Voltage and current output?
     
    Last edited: Jul 11, 2017
  14. x10

    x10

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    Jul 11, 2017
    Just using your standard 2-prong sealed power adapters you plug into an AC outlet. I have a few 12VDC and 5VDC all under 1A but way over 4mA.
     
  15. Minder

    Minder

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    Apr 24, 2015
    When connecting a DC motor directly across the supply, there is high initial current until the motor gathers rpm and provides the generated BEMF.
    At switch on it is effectively a very low resistance.
    M.
     
  16. x10

    x10

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    Jul 11, 2017
    right now my problem is getting the relay switch to close... i'm sure my adapter amperage is plenty to drive motor at power-up
     
  17. kellys_eye

    kellys_eye

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    Jun 25, 2010
    The relay (via that driver board) will either operate with a high or a low signal (it doesn't spec which other than a 4mA requirement that 'may' signify being pulled 'low' by a logic port).

    You can do no harm by testing the board stand-alone. With the 12V supply attached (Vcc and GND) use a shorting link to link over the control signal to the Vcc OR the GND lines and check for relay operation.

    If it needs a 'low' signal then using the DC as delivered by the adapter when powered ON through the X10 signal won't cut it as you'd have to switch it OFF to get it! Thereby losing the power to the relay board.

    You need a separate 12V supply for the relay board and another (from the X10) to do the switching - note that both power supply negative lines need to be common.
     
  18. x10

    x10

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    Jul 11, 2017
    Thanks. This sounds like the problem I'm having. On the bottom is printed "low level trigger". I guess that means I need to unshort the IN pin to activate. I will try it today. Using a separate $10 X10 controller just for the signal might be a bit expensive in the long run. Maybe I can use a separate 89 cent relay to unshort. But it might be "turtles all the way down".
     
  19. kellys_eye

    kellys_eye

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    Not 'un short' but GROUND the pin.. leaving it 'un shorted' is called 'floating' and it tends to float 'high'.
     
  20. x10

    x10

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    Jul 11, 2017
    thanks... who'd a thunk it... an "anti-signal"... works great in phase one which is getting relay to work... looks like i will need 4 relays for each motor... 2 for each direction... power and ground... now the question is how am i going to mount these MFs... no holes... thanks again
     
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