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LM317 voltage regulator question (for delta fan)

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Feb 2, 2001
Delray Beach FL
A recent thread mentioned using a Radioshack LM317 voltage regulator to modify the juice going to a delta fan. I had thought about just using a toggle switch between the 12 and 7 volt lines, but this seemed more interesting.

Having just picked up said regulator (LM317T - note the T), I see that the input is supposed to be 28 volts. Is this the wrong model or will it work ok with a 12 volt input?

I also read about using a rheostat, but I think those are designed to handle less watts than the fan uses and might burn out. I don't think that I want to take the risk of that fan not working at all.
That is a maximum rating. I am putting together an article for the front page going through the whole process, if you can wait a day or two.

Oh, thanks. That will help a lot. I went to RS with a friend who understands the diagram on the back but I sure don't. So I ended up with 5 thingies (220 ohm resistors, two types of capacitors, a volume control, and the LM317. And the hsf isn't even arriving until tomorrow. (new vantec, I hope it is ok). I have a 12 volt case fan to practice on.

So thanks, we can use the help putting it together. Seems like there should be a market for those of us who are solder-challenged.

I will be going away for a week starting this Friday and will look forward to your article. I think I can wait to assemble it until I get back.

Yes! And I get to drill a hole through the case so I can install the knob! Or, I can use an open slot. The possibilities of more tinkering are endless.