12v Fan Reduce speed in every minute interval using 555 timer.

[Genrick Son]

Hi guys im pretty new to electronics,

I know its to much , Im looking for a simple schematic design about 12v fan that can automaticaly reduce its speed in a minute interval . From 100% speed to 60% to 30% until zero.

regards genrick son,

 

[Alec_t]

Welcome to EP!
Does the fan have a speed-control input? Model/specification?

 

[Genrick Son]

Welcome to EP!
Does the fan have a speed-control input? Model/specification?

No sir , just a normal DC fan .

 

[nepow]

Hi guys im pretty new to electronics,

I know its to much , Im looking for a simple schematic design about 12v fan that can automaticaly reduce its speed in a minute interval . From 100% speed to 60% to 30% until zero.

regards genrick son,

Do's this nead to happenevery time the fan switches on? and how accurate does the timing need to be.

 

[AnalogKid]

To go from full speed to off in 1 minute you gradually reduce the energy available to the fan.

There are two basic ways, analog and digital. Analog means a voltage regulator where either a control voltage is decreased slowly or the negative feedback that establishes the output value is changed slowly. Digital usually means pulse width modulation (PWM), where the duty cycle of the 12 V pulses is changed slowly from 99% to 1%. Note that normal brushless DC (BLDC) fans will not run at very slow speeds, so no matter which method you use, the fan might slow down to maybe 20-25% and then just stop.

What kinds of parts and test equipment do you have available to you, what is your build and test skill set, etc. Which method sounds like something you want to try?

ak

 

[Genrick Son]

Yes sir , every 6 minutes or less , 4 intervals which the last one is turn off .

thanks for fast replies

 

[Genrick Son]

To go from full speed to off in 1 minute you gradually reduce the energy available to the fan.

There are two basic ways, analog and digital. Analog means a voltage regulator where either a control voltage is decreased slowly or the negative feedback that establishes the output value is changed slowly. Digital usually means pulse width modulation (PWM), where the duty cycle of the 12 V pulses is changed slowly from 99% to 1%. Note that normal brushless DC (BLDC) fans will not run at very slow speeds, so no matter which method you use, the fan might slow down to maybe 20-25% and then just stop.

What kinds of parts and test equipment do you have available to you, what is your build and test skill set, etc. Which method sounds like something you want to try?

ak

Thermistor, LM35, thermocouple , Im still new to electronics sir , we would like to use it in our project which the fan will use as a blower to cook rice .. Can you make a simple schematic about this sir ? which probably every 6 minutes the blower changes its speed in 4 stages .. at the last stage it is now turn off .

 

[garublador]

This may be an instance where a simple microprocessor might be the best solution.

 

[Genrick Son]

This may be an instance where a simple microprocessor might be the best solution.

can you make a simple schematic about it sir ?

 

[Colin Mitchell]

Your requirement is very complex and beyond a beginner.

 

[CDRIVE]

No sir , just a normal DC fan .

I googled "Normal DC Fan" but didn't get any hits. My guess is there's no such animal. Perhaps if I try "Abnormal DC Fan" it will point me to a normal one.

Chris

 

[Colin Mitchell]

He is possibly talking about the highly sophisticated brushless DC motor.

 

[AnalogKid]

Really? We go through a few thousand a year and they're pretty much dumb as dishwater.

ak

 

[Colin Mitchell]

I have explained how they work on my website and you would still not comprehend their operation.
They are the most advanced DC motor. Their operation is brilliant and it is only through the advent of the HALL EFFECT device that they were able to work.

Explain to me the simplest question: How do they start to rotate?

 

[thaers3d]

you can try to modify the pwm circuit?
like this one:
http://www.tronixworld.com/home/electronic-circuits/pwm-motor-speed-control/

 

[CDRIVE]

This may be an instance where a simple microprocessor might be the best solution.

I don't think there's any maybe about it. It will be a dirt simple circuit for a PMDCM (Permanent Magnet DC Motor) but he needs to start by selecting the motor/fan he's going to use and post the motor specs, so we can design around it.

Chris

 

[AnalogKid]

I have explained how they work on my website ...

A side question - did you consider, for even one millisecond, including a link?

ak

 

[CDRIVE]

A side question - did you consider, for even one millisecond, including a link?

ak

The reason you missed it is because you're not psychic like me. On the other hand the OP can click on Collin's profile. This should take him to all of Collin's posts where he rarely fails to post anything but the link.

Chris

 

[AnalogKid]

On the other hand the OP can click on Collin's profile. This should take him to all of Collin's posts where he rarely fails to post anything but the link.

OTOOH, the OP has a total of 7 posts, 5 in this thread. If he is as new to forums as he is to electronics, he would need to read your mind in order to read Colin's. Double scarey.

ak

 

[CDRIVE]

OTOOH, the OP has a total of 7 posts, 5 in this thread. If he is as new to forums as he is to electronics, he would need to read your mind in order to read Colin's. Double scarey.

ak

Ha, not as scary as my nephew Marty's mind!

Chris