How does a Poteniometer control motor time delays

Discussion in 'General Electronics Chat' started by sherlock ohms, Jan 28, 2014.

  1. sherlock ohms

    Thread Starter New Member

    Dec 24, 2013
    Follow up questions from threads a few weeks ago..

    I have a pellet stove with an auger motor controlled by a Timer/Potentiometer combination which cycles the motor on and off.
    The motor "on" cylce is a constant three seconds regardless of the Potentiometer setting.
    What does change with the pot dial setting is the delay period between auger motor "on" cycles.
    I have not been able to understand clearly how this happens.

    I understand the pot is reducing the current flow to some timer component as it is dialed up, but so what? How does varied current through the pot translate to shorter/longer delay periods on the motor? I see how the motor could cycle on and off via a time delay relay, but wouldn't that mean a uniform off period, not a vaired one.? I know the pot is somehow varying the off period and that is the part that is over this beginner's head.

    thanks again to one and all for sharing your knowledge, scott
  2. mcgyvr

    AAC Fanatic!

    Oct 15, 2009
    Think of the time delay as a bucket of water (when it tips over and empties your motor is on..then it tips back up to be refilled).. That "resistor" might be changing the flow rate into the bucket.. So at some setting it takes longer to fill the bucket and tip it over.. Then at another resistance it might fill the bucket faster..
    sherlock ohms likes this.