How do I drive these Delta fans with varying speed? - Page 1
Forum section: electronics / projects

author: iamdarkyoshi
author_rank: Frequent Contributor
timestamp: February 11, 2017, 01:25:08 am
content: Hello everyone, I have recently obtained a box of like 30 or so delta fans from a source that shall remain unnamed for now.Update: Broke a bit of the plastic off the back of one of the fans and found the PCB labels for the wires:Black - GNDRed - VINYellow - PWMBlue - O/FThe red and black are positive and negative, but the yellow and blue wires have me stumped.I thought they might be the standard yellow tach and blue PWM wires of a standard PC fan, but they aren't, I terminated them in a 4 pin fan header and the fan ran at full speed. So I thought maybe my dell test motherboard was being... dell, so I just connected the fan to a 12v power supply and touched the blue wire (normally a PWM input) to ground, expecting it to shut down the fan (0% PWM) Nothing changed, still ran at full speed. So I tried the yellow wire (normally a tach wire on most fans) and oddly, it shut the fan down. So I figured maybe delta just switched the tach and PWM colors around, so I did the same, and the fan didn't move at all when connected to my dell testbench. Then I tried voltage controlling it, it was still pretty fast at 7v and wouldn't even move at 5v, so voltage control seems unlikely.Any ideas? I can't seem to find any datasheets for the 4 pin flavor of this fan, only 2 and 3 pin versions.Thanks!

author: iamdarkyoshi
author_rank: Frequent Contributor
timestamp: February 11, 2017, 01:40:21 am
content: Update: Broke a bit of the plastic off the back of one of the fans and found the PCB labels for the wires:Black - GNDRed - VINYellow - PWMBlue - O/FThinking maybe they use 12V PWM instead of 5V PWM, I put 5V on the PWM pin to simulate my motherboard outputting 100% PWM, and unlike the motherboard, this simulated setup ran the fan at full speed.Now I'm really confused.

author: mariush
author_rank: Super Contributor
timestamp: February 11, 2017, 01:41:10 am
content: See1. Datasheet for the fan :http://partner.delta-corp.com/Products/FanUploads/Specification/AFB120x38mm.pdf2. Official Intel fan specifications :http://formfactors.org/developer%5Cspecs%5CREV1_2_Public.pdfnote that wire colors are changed from official intel specification :1. ground : black2. voltage : red3. sense : yellow (2 pulses per rotation of fan)4. control : pwmAs datasheet says above, the fan features -R00 or -F00 functions for controlSeehttp://www.delta.com.tw/product/cp/dcfans/download/pdf/general_info.pdf, see pages 7 and 8The fan should also accept the pwm signal as specified in the intel datasheetBasically any proper fan controller should work with this fan, just put the wires in the correct order in the connector.

author: isometrik
author_rank: Regular Contributor
timestamp: February 11, 2017, 01:44:55 am
content: Maybe this document (http://www.delta.com.tw/product/cp/dcfans/download/pdf/general_info.pdf) could be of some help ?Page "v" let's you decode their part number, while the rest of the document provides diagrams of possible options (Frequency Generator Output, Rotation Detector Output, Temperature Control "Sensflow", and PWM Control). The document does not provide the wire colour scheme however.You might have to sacrifice one and perform an autopsy.

author: iamdarkyoshi
author_rank: Frequent Contributor
timestamp: February 11, 2017, 01:48:26 am
content: Quote from: mariush on February 11, 2017, 01:41:10 amThanks for the detail page, I didn't see that before.Quote from: isometrik on February 11, 2017, 01:44:55 amSo I broke a bit of the plastic off the back of one of the fans and found the PCB labels for the wires:Black - GNDRed - VINYellow - PWMBlue - O/FBut connecting the fan to my motherboard with the blue and yellow swapped from the usual pinouts, (now blue on tach and yellow on PWM) it doesn't spin at all.

author: isometrik
author_rank: Regular Contributor
timestamp: February 11, 2017, 02:09:34 am
content: Section 7 (page "vii") of thehttp://www.delta.com.tw/product/cp/dcfans/download/pdf/general_info.pdfdocument shows that the PWM input (yellow wire, as you found out) will stop spinning at 0% duty cycle, while maximum RPM will be obtained at 100% duty cycle.You have already demonstrated that by grounding the yellow wire (PWM input) the fan will stop spinning.The document also mentions that the PWM input voltage ranges are 0.0V to 0.4V for a LOW, and 2.8V to 20V for a HIGH. Thus, connecting the yellow wire to +12V should have it spin at its maximum RPM. The document also mentions that the PWM input will draw 40µA to 20mA. Finally, keep in mind that the PWM signal's frequency must be somewhere between 30Hz and 30kHz.Now, if you look at the Intel fan specification (http://formfactors.org/developer%5Cspecs%5CREV1_2_Public.pdf) document provided by mariush, section 2.4 states that a fan must not sink more than 5 mA.Your motherboard probably cannot source enough current on its PWM control output pin for this fan.

author: iamdarkyoshi
author_rank: Frequent Contributor
timestamp: February 11, 2017, 02:13:02 am
content: Quote from: isometrik on February 11, 2017, 02:09:34 amThat could possibly be the culprit. I need to buy some new leads for my multimeter though to do any current measurements...Edit: Now that I think about it, maybe not. If the motherboard can't sink enough current, then it should theoretically go full speed rather than not doing anything, which is what it does unless I disconnect the PWM pin.

author: NiHaoMike
author_rank: Super Contributor
timestamp: February 11, 2017, 04:19:49 am
content: It could be that the fan has a custom firmware that accepts something other than the standard 25kHz PWM. I have a Delta fan intended for a Daikin indoor unit and it would react erratically to 25kHz PWM but works great with 1kHz inverted PWM.I suggest connecting a function generator or even a 555 and play around until you find something that controls the fan properly.