The fan is labeled:<\/p>\n
DC BRUSHLESS<\/p>\n
Model\u00a0 AFC0912DE<\/p>\n
Dell P\/N P2780<\/p>\n
DC12V\u00a0 2.50A<\/p>\n
Delta Electronics, Inc.<\/p>\n
I work with Dell PCs and I had a CPU fan laying around that came out of an older Optiplex PC.\u00a0 I had connected it up to a 12V power supply much earlier, and it acted very odd.<\/p>\n
FIrst off, older fans had two wires: a red positive 12V and a black ground.\u00a0 Later, fans came with three wires: red for +12V, black for ground and a white or yellow wire for the tachometer to tell the MoBo that the fan was spinning,\u00a0 But this fan was different.\u00a0 Instead of three, it had four wires: red, black, white and blue.\u00a0 So I connected the 12V up to the red and black wires. \u00a0 It would\u00a0 start out slow, and gradually speed up to a high speed, then, Kerchunk!\u00a0 It would abruptly come to a near halt.\u00a0 then it would repeat the process.\u00a0 It was either putting out almost no air, or whining at high speed and drawing over 2 amps from the power supply.\u00a0 I kind of gave up and tossed it in the spare parts bin, where it sat for a long time.<\/p>\n
I finally got around to try to get it to work.\u00a0 I went by the old maxim “An hour in the library is worth ten in the lab.”\u00a0 I went online and searched for information about the fan.\u00a0 I came across others who were trying to get another fan to replace their noisy Dell fan.\u00a0 Finally I found out that the red and black wires were the positive 12V and negative, and the white and blue wires were the tach and PWM speed control wires.\u00a0 But I did not find any information about what the PWM control was or how it worked.<\/p>\n
So I started experimenting with the PWM control line.\u00a0 I tried a few different value resistors from +12V to the blue wire, and from negative to the blue wire.\u00a0 I found that if I put a 1k resistor from the blue wire to negative, the fan stopped acting weird and would run at a constant speed, not very fast but at least it was steady and quiet. \u00a0 Now I can connect the fan to a 12V wall wart, and plug it in, and set it on its edge on the table without having to worry that it was going to jump off and fall on the floor due to its kerchunking behavior.<\/p>\n
Back to experimenting…<\/p>\n","protected":false},"excerpt":{"rendered":"
The fan is labeled: DC BRUSHLESS Model\u00a0 AFC0912DE Dell P\/N P2780 DC12V\u00a0 2.50A Delta Electronics, Inc. I work with Dell PCs and I had a CPU fan laying around that came out of an older Optiplex PC.\u00a0 I had connected it up to a 12V power supply much earlier, and it acted very odd. FIrst <\/p>\n (Read More…)<\/a><\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[9,74],"tags":[],"class_list":["post-3181","post","type-post","status-publish","format-standard","hentry","category-computers","category-electronic-components"],"_links":{"self":[{"href":"https:\/\/rustybolt.info\/wordpress\/index.php?rest_route=\/wp\/v2\/posts\/3181","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/rustybolt.info\/wordpress\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/rustybolt.info\/wordpress\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/rustybolt.info\/wordpress\/index.php?rest_route=\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/rustybolt.info\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=3181"}],"version-history":[{"count":5,"href":"https:\/\/rustybolt.info\/wordpress\/index.php?rest_route=\/wp\/v2\/posts\/3181\/revisions"}],"predecessor-version":[{"id":7845,"href":"https:\/\/rustybolt.info\/wordpress\/index.php?rest_route=\/wp\/v2\/posts\/3181\/revisions\/7845"}],"wp:attachment":[{"href":"https:\/\/rustybolt.info\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=3181"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/rustybolt.info\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=3181"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/rustybolt.info\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=3181"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}