What are the 3 wires of a computer fan hooked to?
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Martaine2005
- May 12, 2015
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Red is 12V+, black is GND/neg- and yellow is the signal wire.
Be sure that yours is 12V as some are 5V.
Be sure that yours is 12V as some are 5V.
Thank you. I applied 12 V+ to the red wire and the fan does indeed run. Second question; From reading customer reviews of this cooler, I gathered that the fan has two speeds. Is the fan speed determined by a signal on the yellow wire? e.g. 0 V = low speed and 12 V+ = high speed? By the time you read this, I most likely will have tried applying a signal to the yellow wire. The reason I was not this brazen with moving my 12 volts to the red wire is because experience has taught me that applying 12 V to a 5 V motor winding generally damages the winding. I have already had 12 V on yellow wire and fan still operates so I am moderately confident that the experiment will not destroy my fan.
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Hello,
The yellow wire can have several functions depending on the fan type number.
There are fans that show pulses on the yellow wire from a tach sensor.
There are fans that need a pwm signal on the yellow wire to control the speed of the fan.
There are fans that use the yellow wire as an alarm signal when the fanspeed drops below a certain level.
Read the datasheet of the fan for the function of the yellow wire.
Bertus
The yellow wire can have several functions depending on the fan type number.
There are fans that show pulses on the yellow wire from a tach sensor.
There are fans that need a pwm signal on the yellow wire to control the speed of the fan.
There are fans that use the yellow wire as an alarm signal when the fanspeed drops below a certain level.
Read the datasheet of the fan for the function of the yellow wire.
Bertus
roughshawd
- Jul 13, 2020
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A fan is sometimes designed to speed up or slow down based on the cooling needs of the system. That way you don't over cool the CPU creating monitor interference. Usually the third wire is a clock wire that gives RPM. The red being hot, and the black being not, if you put a small power supply in line with an LED on the signal line, it should flash everytime the motor turns 1 RPM...= solid on LED, but not suggested!
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