12vdc resistor speed control

Discussion in 'The Projects Forum' started by jdparnel, Mar 22, 2010.

  1. jdparnel

    Thread Starter New Member

    Mar 22, 2010
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    I am looking to wire a 12-14vdc (30A max) fan in my car with variable speed control. I would like it to be controlled with a resister style temperature sensor. Not sure wether to go with PWM, 555 timer or what? I have build a PWM circuit in class but nothing with high current.

    Does anyone have a circuit diagram?
     
  2. retched

    AAC Fanatic!

    Dec 5, 2009
    5,201
    312
    Re-inventing the wheel. You can get automotive thermostats that close a circuit at a preset temp. You can use any 12vDC motor connected to the battery and the stat.

    The PWM is the only thing Im finding odd here. Why variable speed? Is this for the engine compartment or passenger compartment?
     
  3. jdparnel

    Thread Starter New Member

    Mar 22, 2010
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    its for the engine compartment....i don't want the fan to just swith on when the temp gets to a certain point then cut off.... i have a v8 engine in a small truck and want more control of the engine temperature. I want the fan to come on at 50% then raise to 100% depending on the engine temperature, which i want to wire to a variable resistance temperature sensor.
     
  4. retched

    AAC Fanatic!

    Dec 5, 2009
    5,201
    312
    What is the MAX temperature the thermistor would have to endure? 260f?

    You could use a thermistor to report the temperature to a pic, then use the PWM to change the speed of the motor.
     
  5. jdparnel

    Thread Starter New Member

    Mar 22, 2010
    3
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    That would work I just need help wiring the circuit
     
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