Capacitor for a PWM controlled DC motor

Discussion in 'General Electronics Chat' started by atferrari, Jul 21, 2010.

  1. atferrari

    Thread Starter AAC Fanatic!

    Jan 6, 2004
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    I am currently completing the assembly of a small coil winding machine driven by a 12V/45 mA PWM-controlled motor.

    At two different robotic oriented sites I have found the recommendation of adding a capacitor to its terminals allegedly to protect the motor.

    If true, what is the actual reason to use it? How to calculate / check the value of C?
     
    Last edited: Jul 21, 2010
  2. jpanhalt

    AAC Fanatic!

    Jan 18, 2008
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    I think the 4QD site explains it. You can find a lot of interesting information there. Are you using two mosfets or just one? Here is the link to the first section in which the "main" capacitor for a half bridge is described: http://www.4qdtec.com/pwm-01.html

    John
     
  3. atferrari

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    Jan 6, 2004
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    Four 2N1711 (bipolar) in a full H bridge driven by PWM signals from a 18F452.

    Thanks for the link, John.
     
    Last edited: Jul 22, 2010
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