Case fan with 3-pin connector

Old 06-27-06, 01:14 AM
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Join Date: Mar 2006
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Case fan with 3-pin connector

I'm looking to add an additional case fan to my computer. The one I purchased has the red and black power through a regular 4-pin Molex connector from the power supply and a separate yellow wire for the RPM reading as a single pin on a 3-pin plug for the motherboard. Here's my questions:

1. The fan states that it is temperature controlled speed, but how can this be with the power hooked up to a continuous 12 volts? Isn't the yellow wire just for the RPM reading, and the fan needs to be connected to the motherboard for speed control?

2. The fan itself shows a range of 1950 - 3400 RPM. I would expect it to run at full speed as it's connected, but my management software shows it running at 1800 RPM. Why?

The fan is an Ultra Thermo-Control Fan with some specs here:


Old 06-28-06, 12:48 PM
Join Date: Apr 2004
Location: Ontario Canada
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It has a temperature sensor to control motor speed. The yellow wire is only for reading the motor's speed.

It could be you have the speed multiplier incorrectly set, or it is running at minimum speed.

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