Connect with us

latching pushbutton help

Discussion in 'General Electronics Discussion' started by iKatoz, Nov 28, 2015.

Scroll to continue with content
  1. iKatoz

    iKatoz

    20
    0
    Nov 28, 2015
    Hi everyone,

    I want to control a motor via four buttons, each button would run the motor at a predetermined speed. By pressing one of four buttons the engine starts, but I don't know how to detach the relay (supposedly) by pressing another button to change the speed of the motor.

    I tried to draw a circuit diagram but I can't solve the problem, anyone can help me out?

    Thanks
     
    Last edited: Nov 28, 2015
  2. Alec_t

    Alec_t

    2,947
    803
    Jul 7, 2015
    Welcome to EP!
    What is the motor spec? AC? DC? Brushless? Voltage? Current? .....?
     
  3. Tha fios agaibh

    Tha fios agaibh

    2,152
    725
    Aug 11, 2014
    Screenshot_2015-11-28-12-12-29-1.png Just use normally closed contact(s) to break relay(s)
    You could wire all the nc contacts in series, so any button pressed would break the relay coils.
     
  4. iKatoz

    iKatoz

    20
    0
    Nov 28, 2015
    Currently I don't know, I have an AC drill motor (500w) but I would buy a DC motor (24V) but I don't now if it's possible to slow down the motor to 50-200RPM (the range of the 4 buttons)

    Are you talking about latching relay or monostable relay?
     
  5. Tha fios agaibh

    Tha fios agaibh

    2,152
    725
    Aug 11, 2014
    Any type of relay would work. A latching relay would probably not be the best option.
     
  6. iKatoz

    iKatoz

    20
    0
    Nov 28, 2015
    I think I confused the meaning of "latching" with "bistable". However I don't understand how to use the NC contacts for what I have to do
     
  7. Minder

    Minder

    3,076
    657
    Apr 24, 2015
    If you are trying to reverse a ac drill motor they are usually Universal motors, the wound field is in series with the armature, the field has to be reversed with respect to the armature.
    A DPDT SW with centre off will do it.
    With these motors, usually triac control is used.
    M.
     

    Attached Files:

  8. Tha fios agaibh

    Tha fios agaibh

    2,152
    725
    Aug 11, 2014
    The nc contacts are all in series, by pushing any button you kill power to one side of circuit.
    Just use a separate relay contact to feed the motor at whatever speed you want to send to it.
     

    Attached Files:

    hevans1944 likes this.
  9. iKatoz

    iKatoz

    20
    0
    Nov 28, 2015
    I want also reverse the motor but I know how to do that part of the circuit.


    I tried to draw a scheme but it's probably wrong
    I use the second NO contact of the buttons to send an impulse to the activated relay but I don't know how the relay that i'm trying to activate might react
     

    Attached Files:

  10. Minder

    Minder

    3,076
    657
    Apr 24, 2015
  11. Tha fios agaibh

    Tha fios agaibh

    2,152
    725
    Aug 11, 2014
    Didn't like my sketch?
     
  12. hevans1944

    hevans1944 Hop - AC8NS

    4,606
    2,151
    Jun 21, 2012
    I liked your sketch.
     
    Tha fios agaibh likes this.
  13. iKatoz

    iKatoz

    20
    0
    Nov 28, 2015
    Actually I didn't understand everything

    I forgot to ask,is there a monostable relay in multisim 11? can't find it
     
  14. Tha fios agaibh

    Tha fios agaibh

    2,152
    725
    Aug 11, 2014
    I Just drew simple relay logic that has a holding contact to latch relay coil power.
    No monostable needed.
    All you need is pushbuttons with seperate open and closed contacts. And a few relays with contacts heavy enough to handle motor current.

    I don't know what multisim 11 is. ?
     
  15. Minder

    Minder

    3,076
    657
    Apr 24, 2015
    That type of control or switching is called a 'Radio Button.'
    It can be set up with relays, or there off the shelf ones.
    Still no word on the type of motor??
    Seems like Over-engineering going on.
    M.
     
  16. iKatoz

    iKatoz

    20
    0
    Nov 28, 2015
    I can't find anything on the internet about this type of control
    However, I think I'll open another thread specific for the motor but I think something like that would be fine http://it.rs-online.com/web/p/motori-cc/2483671/


    it's a program to simulate circuits

    However, is my scheme wrong?
     
  17. Tha fios agaibh

    Tha fios agaibh

    2,152
    725
    Aug 11, 2014
    Old school, pencil and paper.
    A little hard to follow on your drawing because your buttons look like relay contacts. Anyway, the speed selection is the easy part to do.
    Your primary concern should be:
    1, What type of motor am I using?
    2, Is it capable of being slowing down?
    3 How can this be accomplished?
    What circuit is suited for this speed control?
     
  18. Minder

    Minder

    3,076
    657
    Apr 24, 2015
    There is PWM controllers on ebay for these kind of motors for about $5.00. ebay 141647039024
    They are designed along these lines.
    http://www.discovercircuits.com/DJ-Circuits/simplepwm2.htm
    Both of the above are controlled by a potentiometer, which you could replace with pre-set resistors.
    You also have to decide if you need bi-directional control.
    M.
     
    Tha fios agaibh likes this.
  19. iKatoz

    iKatoz

    20
    0
    Nov 28, 2015
    Last edited: Nov 28, 2015
  20. Martaine2005

    Martaine2005

    3,408
    926
    May 12, 2015
    I like the sketch too John..
    Long live Old Skool..

    Martin
     
    Tha fios agaibh likes this.
Ask a Question
Want to reply to this thread or ask your own question?
You'll need to choose a username for the site, which only take a couple of moments (here). After that, you can post your question and our members will help you out.
Electronics Point Logo
Continue to site
Quote of the day

-