need 110v dc motor speed control circuit

Discussion in 'The Projects Forum' started by er.pratikagrawal, Apr 26, 2011.

  1. er.pratikagrawal

    Thread Starter New Member

    Apr 26, 2011
    4
    0
    hiii friends i am a new on this site..please help to guide on my project..

    i have 110v dc motor 0.8 amp & 80w.

    i want a circuit 2 controle speed of motor.

    using scr or any other method but not microcontroler.

    please provide me if possible.

    Regards
    Pratik Agrawal
     
  2. electronis whiz

    Well-Known Member

    Jul 29, 2010
    519
    27
    i would use a fan speed controler made for an ac fan. there are 3 types of controler. there are the 3 position switches, dimmer type switches for motors. and therer is the transformer type. i have a transformer type i got mine from american science and surplus if they still have them ia am not sure. this switch was made for ac but i have used it to control small dc motors <12Vdc it works good. this switch has a transformer looking part the one lead comes off of. and the other lead goes into a 3 position switch witch ajusts the resistence in the trancformer. they are sing the transformer like a big resistor. however this only has 4 positions low med hi and off. i beleve it was made by fasco. if this wont work for yu look for a speed control switch made for a hand power drill. most of thes drills use a universal ac/dc motor so the switch should work on dc also. however that is only a gues.
     
  3. Adjuster

    Well-Known Member

    Dec 26, 2010
    2,147
    300
    Some motors are "universal" AC/DC, but some switches definitely are not. In particular, SCRs normally cannot switch off in a continuous DC environment. (May be OK with unsmoothed DC and a resistive load, but with an inductive load like a motor the "gaps" in unsmoothed DC might not be long enough.)

    You may of course have in mind a scheme where the SCR would be performing its title role as a controlled rectifier with an AC input, but this is not clear from your description.
     
  4. Bernard

    AAC Fanatic!

    Aug 7, 2008
    4,170
    395
    If you can find a copy of GE SCR Manual, you'll have answer. Sorry but it smells of high V, so a no-no here.
     
  5. er.pratikagrawal

    Thread Starter New Member

    Apr 26, 2011
    4
    0
    Thanks for your suggestions friends . but i want to produce pwm signal which can be controle by variable resistor through this PWM signal i want to drive 110v dc motor by using IGBT or SCR.

    PLEASE DO SOME REPLY IF POSSIBLE.

    Regards,
    Pratik Agrawal.
     
  6. BillB3857

    Senior Member

    Feb 28, 2009
    2,400
    348
    Where are you getting a 110V DC source? Or, are you using 120V AC as your source and have a DC motor you want to run. Makes a big difference. If an AC source is used, then phase controlled SCRs will work for you.

    Another option, if AC source, with such a small motor, use a light dimmer and a bridge rectifier.
     
  7. CDRIVE

    Senior Member

    Jul 1, 2008
    2,223
    99
    Is this pure DC (filtered) or pulsating DC?
     
  8. er.pratikagrawal

    Thread Starter New Member

    Apr 26, 2011
    4
    0
    friends i have 110v ac transformer the output of this transformer is converted in 110vdc by using bridge rectifier.now i want to run my 110vdc motor in controled manner( speed control).

    dimmer circuit is not usefull in my application.please give me any other solutions.
    i want to generate PWM through this pwm i want to control my motor.,,is there any circuit u have???

    Regards,
    Pratik Agrawal.
     
  9. BillB3857

    Senior Member

    Feb 28, 2009
    2,400
    348
    Can you explain why a dimmer would not work for you? It would be placed in series with one of the transformer leads feeding the bridge. After its output goes through the bridge rectifier, you have full wave phase angle control of the output to the motor.

    Also, can you further describe the motor. Just because it has brushes doesn't always make it a pure DC motor.

    I use a light dimmer to drive an electric leaf blower with no problems. It has a 'universal' motor.
     
  10. CDRIVE

    Senior Member

    Jul 1, 2008
    2,223
    99
    I don't want to sound like an echo but the statements and questions by Bill are correct and the questions need to be answered. If it's unfiltered DC a phase controlled SCR would seem logical here
     
  11. er.pratikagrawal

    Thread Starter New Member

    Apr 26, 2011
    4
    0
    friends dc o/p is filtered and i have to control the speed of motor by pwm.This is my project guyz....

    Regards,
    Pratik Agrawal.
     
  12. BillB3857

    Senior Member

    Feb 28, 2009
    2,400
    348
    So this is a homework assignmet, right? If so, maybe a moderator can move to the proper area and you will get more appropriate answers rather than someone simply doing your homework for you.
     
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