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General Category => General Discussion => Topic started by: chacaman on August 24, 2011, 01:42:29 AM

Title: 12V 15AMP Circuit for test fan failures
Post by: chacaman on August 24, 2011, 01:42:29 AM
hi, guys is posible to make a circuit for test a fan failure for example 12V 15AMP fan from a car ?
when fan failure active a buzzer or led in the dash....

thanks
Title: Re: 12V 15AMP Circuit for test fan failures
Post by: cheerio on August 24, 2011, 02:46:54 AM
quick and dirty you can just count the rpm with a light barrier.
Title: Re: 12V 15AMP Circuit for test fan failures
Post by: kam on August 24, 2011, 09:01:57 AM
d you have more details about the fan? has the fan any wire with signal output? if not, then you should follow cheerio's advice. The light barrier circuit will generate a pulse every time the fan blade cuts the light barrier. You can then drive this pulse to this circuit:

PC Fan Failure Alarm (http://pcbheaven.com/circuitpages/PC_Fan_Failure_Alarm)

This circuit resets whenever a pulse arrives, but if a pulse does not arrive for some time (eg if the fan blades stop turning) then the circuit activates the alarm.

Title: Re: 12V 15AMP Circuit for test fan failures
Post by: chacaman on August 24, 2011, 14:16:20 PM
thanks Cheerio and administrator for your time and help
in my case my fan only have two wires 12V+ and ground

guys i found this:

http://www.pyroelectro.com/tutorials/digital_tachometer_rpm/img/schematic.png
onlyne i need the part of the IR Emmiter and Detector and the ciruit of this page

one question in the  schematic
the ir detector is connect to led rc2 in my case a will use the circuit from this site and connect to the rpm signal
thanks
Title: Re: 12V 15AMP Circuit for test fan failures
Post by: kam on August 24, 2011, 23:54:27 PM
i suppose that the LED is a simple 3.2V IR LED (not 1.3V) and the receiver could be any IR transistor.
Title: Re: 12V 15AMP Circuit for test fan failures
Post by: _pike on August 25, 2011, 00:30:44 AM
you can also built this one..........  http://pcbheaven.com/circuitpages/IR_Short_Distance_Beam_Cut_Detector/