PWM motor speed controller

Description.
This circuit is designed as per a request made by Mr Vinoth from India. His requirement was a 12V/5A DC fan motor controller. I think this circuit is sufficient for this purpose. Quad 2 input Schmitt trigger IC CD4093 is the heart of this circuit. Out of the four Schmitt triggers inside the 4093, U1a is wired as an oscillator with adjustable duty cycle. The U1b, U1c, U1d buffers the output of the oscillator to drive the switching MOSFET Q1.The MOSFET drives the DC motor according to the switching pulse obtained from the oscillator. When R1 is varied the duty cycle varies and so do the speed of the motor. Diode D3 acts as a freewheeling diode.

Circuit diagram with Parts list.
pwm-dc-motor-speed-controller

Notes.

  • Assemble the circuit on a good quality PCB.
  • IC U1 should be mounted on a holder.
  • U1a, U1b, U1c, U1d are part of the same IC CD4093; so power supply is shown connected only once.
  • The12V power supply for this circuit must be able to handle at least 5A.
  • A heat sink is recommended for Q1.
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15 Responses to “PWM motor speed controller”

  • shehan says:

    sir we have made a pwm circuit with 12v and it is working fine..we used a 12v motor and it is well controlled using pwm.but sir we want to control a 230v motor using pwm.can you tell me a method..

    thank you sir..

  • Surya Prakash says:

    Sir,
    I am having the below mentioned phone set which went out of order recently, i tried to get the circuit diagram and other service manual to get this repaired. Unfortunately i did’t get it. will you please me help me in this regard any cost i am ready to pay also.

    1. I am having Nokia make cordless telephone which is went out of order few months back the details of which or as follows:
    Long Range Cordless Telephone Model NK 6150 CID
    (FSK/DTMF CALLER ID) Made in Finland.

    Eagerly waiting for your reply to my email

    thanking you,

    yopurs sincerely,

    surya prakash c n

  • DerekOCUK says:

    Admin,
    I need a circuit to control the speed of a 230/240V dc motor, (separately excited field and rotor windings) which is driving an AC alternator. (need speed control to maintain accurate frequency on ac !)
    Please help

  • Edgardo M. Diolola says:

    Dear Admin,
    I wish to have both functional circuits for 110VDC and 230VDC, 5 – 8 AMperes motors, using easy to find componenets / parts.
    Thank you in advance.

  • derek says:

    I am using an owi 007 robot arm and I am trying to control it with a 2 phase dc motor with pwm and a dragon 12 board. The owi 007 robot arm has 5 dc motors that are each powered with 1.5V D batteries (1.5V power supply). Should I use a similar schematic in comparison with yours? If not, then what should I do?

  • admin says:

    Just replacing the MOSFET willnot do the job for you. For high voltages like 230V DC, you need a more efficient circuit. I will add one soon.

  • Karthi says:

    I need to control a 230V, 6A DC motor.
    Can I just replace BUZ10 with IRF840?
    http://skory.gylcomp.hu/alkatresz/IRF840.pdf

    Any other changes needed?

  • PAUL H says:

    HI, I WISH TO BUILD A HIGH POWER 12V DC – DC SIMPLE SPEED CONTROL FOR GOKART, H/DUTY CAR BATTERY, GEARED SERIES TYPE STARTER MOTOR 20 – 30AMP CONTINUOUS. SUITABLE FOR SKILLS OF A ELLECTRICAN. THANKS

  • qwill says:

    Not really.

    I need the PWM and 12 volt Dc supply.

    Would putting suitable thermistor across either, from centre tap of pot to end or would it be better to use lower value pot and have thermistor in series at end.

    It’s for fan on this computer which is very noisy and isn’t needed at full speed all the time. Needs to keep pulse rate constant just vary the duty cycle. What is good/best pulse rate for such a fan.

  • ARTHI says:

    can u pls design nd telme the operation of..”a tamperature controlled..as well as…..remote and manually operatable elctronic regulator”..connected to the same circuit for a single phase fan of “230volts..a.c” i suppose the current rating is 4 to 6 amps..i.e power rating of my fan is “750 to 1150 watts”..!!
    this circuit designed should be..applicable for high power rating of fans [like cooling purpose fans used in industries] …also ..by proportationately increasing the…rating og electronic..components used in it!!..!! plz…provide ma the details..

  • qwill says:

    How would you modify this circuit so that the minimum speed can be set/adjusted and include temperature control so that if temperature rises the fan goes faster.

  • admin says:

    A bridge circuit using high voltage, high current diodes like BY127 diodes will rectify 23OV AC.
    But what is your application.

    For a good design of such a power supply the designer must know the exact application.

    What is your required current rating.
    Do you need regulation.

  • admin says:

    A simple bridge rectifier using BY127 diodes will rectify 230V AC.
    Pls let me know your application.

    For a good designing of such a regulator the designer must know the application.

  • Bharath says:

    can you please help me designing an electrical circuit with 230V input and output of 230v. even electronic components can be used

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