[教學] 解決低速PWM風扇之之聲

本帖最後由 linuxbaba 於 2016-5-28 16:53 編輯

之前,降低85%速度已經之之聲,現在40%速度才有聲
Fan pwm.jpg
2016-5-28 16:45

電解電容10uf 16v 以上,我沒有10uf電解電容,用鉭電容也行....

Why can it reduce the noise?

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本帖最後由 linuxbaba 於 2016-5-29 06:26 編輯

I am using RAMPS, it use FET to PWM the fan,  adding the cap helps because it can remove nasty power spikes into the fan and add the fly back diode to circulate the power when EFT is off,  will keep a steady flow of power into the fan and reduce the noise.

you are right , fly back is wrong

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... fan and add the fly back diode to circulate the power  ...
linuxbaba 發表於 2016-5-29 00:47


d 名唔好亂咁用啦, Flyback diode 有明確的定義, 它是跟 inductive load 成 parallel + cathode 向著電源輸出.  即係咁... https://en.wikipedia.org/wiki/Flyback_diode .  功能就是處理 back emf 的.

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回覆 1# linuxbaba

有啲DC風扇唔受PWM, 80%已經唔轉。試過呢個方法推3cm風扇, 但約50%已行全速。最後好似用到0.1uF電容。最好試下唔同電容值, 會受風扇電流大小影响

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回覆 5# hon2013
我同樣用中國製造3cm風扇,感覺上100%到50%有區別,我只用目測,有機會我會試試0.1uf

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