PWM controllable fans?

Discussion in 'General' started by Veedee, Jul 6, 2017.

  1. Veedee

    Veedee Member

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    Hi Guys,

    I have something very frustrating. After trying a lot of fans for the dual fan setup that I use on my UMOs, I found that it is very hard to find a fan that suits my needs: reliable, and PWM controllable (over two wires). I have tested with dual 25mm fans a while ago, but most of those fans are not PWM controllable (strangely, 2 from a batch of 6 actually were PWM controllable), so I switched to 40mm fans. All of my UMOs (7 in total) use a dual 40mm fan setup. The fans are from a random Chinese brand called 'Lyf'. The fans are PWM controllable and work fine. I also tried fans from a brand called 'MX' but those created so much airflow that the heater couldn't keep up.

    So recently some things changed. Fans started to make noise and burn out after a while. I ordered new fans from the 'Lyf' brand on Ebay and waited for a few weeks before they arrived. When I received the fans, I wanted to give them a try and guess what: the fans only run at full PWM! Apparently, a brand name doesn't say anything when you importing goods from China, because these new Lyf fans are not identical in operation as the old ones. This means they are useless for other materials than PLA in my opinion. I am sick of wasting money on all kinds of fans I can't use.

    Is there anyone who can tell me about a fan brand that makes 40mm fans which can be used on a 3D printer as a part cooling fan. This includes: reliability, but most importantly: PWM controllable over two wires. If you know a fan company that sells them for a reasonable price, please help me out. I have somewhere around 60 fans lying in a box, but I can't use one of them on my printers. :(
     
  2. dc42

    dc42 Well-Known Member

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    I purchased a few 40mm 24V fans from WeDo3DPrinting via eBay and they have been PWM controllable. When one of those became noisy I purchased these http://www.ebay.co.uk/itm/2pcs-Lot-...4010B-Brushless-Cooling-Fan-2pin/262605453522 and they also work well with PWM. This is using Duet electronics which uses a default PWM frequency of 250Hz for fans.

    Some other types of fan need the PWM frequency reduced to 100Hz. A few types, including the E3D 30mm hot end fan, don't work with PWM at all.
     
  3. Veedee

    Veedee Member

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    Awesome, thanks! I found out as well that the 30mm and also the 40mm (xinyujie brand) fans from e3d do not work on PWM signal. I do have a bcn3D sigma with on both hotends a 40mm xinyujie cooling fan, which apparently does work on the PWM signal from the sigma. But the number on the sticker of the fan shows something different from the one that comes from e3d so I think it is a different model.

    Also I have found out that when fans become noisy (especially right after they are switched on), it can be lubricated with bearing grease to make it run smooth again. How: remove the sticker on the back side of the fan, add a bit of grease/oil and it runs like new again.
     

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