Fan noise

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Sietedj
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Fan noise

Post by Sietedj » Thu Mar 03, 2016 5:53 pm

Hi, I'm riding an FM transmitter, tango mounted box, the stereo encoder, power supply and fan 60x60 12v. to remove hot air from inside the box. I have not yet transmitter module but I have done tests with a Chinese I have. The fact is that the hum of the fan is heard, but not much turning up the volume without music is appreciated. I have read that it is better to use fans to 200v but I already have these purchased 12v and wanted to know if you can do something to eliminate that buzz.
Forgiving but the English translator.
Thanks and regards!!!

s2000

Re: Fan noise

Post by s2000 » Thu Mar 03, 2016 6:32 pm

Put the fan on its own 7812 voltage regulator, that may help.

shorty
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Re: Fan noise

Post by shorty » Thu Mar 03, 2016 6:43 pm

If the 12v fan is for a computer and as 3 wires cut off the yellow wire, this should sort the problem, as s2000 said a 12v regulator will also help.

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thewisepranker
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Re: Fan noise

Post by thewisepranker » Thu Mar 03, 2016 7:33 pm

Put a 1,000 uF capacitor across the output of the regulator, alongside any other capacitors you already have there, as close to the regulator as possible.
Also put a 100 nF capacitor across the fan motor terminals, as close to the fan as possible. On the fan motor PCB if you can.

It's also good practice to keep the fan wires as short as possible and stick a ferrite on the positive wire if you have one laying around.

Sietedj
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Re: Fan noise

Post by Sietedj » Thu Mar 03, 2016 7:35 pm

Thanks for the answers. Fans are two wires. I have little idea of how to connect the voltage regulator. I saw some schemes that put two capacitors is necessary for what I do? or only with the regulator it is enough?
Cheers!!

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thewisepranker
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Re: Fan noise

Post by thewisepranker » Thu Mar 03, 2016 7:43 pm

Those schematics with two capacitors are good enough. As per the following:

Image

Fit an additional 1,000 uF capacitor on the output to ground (between pin 3 and pin 2).

s2000

Re: Fan noise

Post by s2000 » Thu Mar 03, 2016 7:51 pm

What voltage is your power supply? Ideally it should be 3v more than the rating of the voltage regulator you use. For example 7812 should be powered from a minimum of 15v to be able to regulate properly.

Sietedj
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Re: Fan noise

Post by Sietedj » Thu Mar 03, 2016 8:24 pm

Thanks thewisepranker, that's what he had seen.
s2000, my source is 12v. you can climb but feeds more things and even support more than 12v. I prefer not to raise the voltage. It will not work the same way?

Sietedj
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Re: Fan noise

Post by Sietedj » Thu Mar 03, 2016 9:27 pm

I found a regulator but I have no capacitors. Anyway I've tried it and follow the noise. I will wait to have the final transmitter to see whether it does or not.
Thanks for the help, you learn a lot in this forum, Greetings !!!

pjeva
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Re: Fan noise

Post by pjeva » Sat Mar 05, 2016 5:58 pm

Put some torroid inductor (from old PC power supply for example) or any RF choke you can find, on + wire of fan supply. It should do the trick, and you must raise input voltage on 7812 at 15v. Othervise it would not work properly.


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Sietedj
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Re: Fan noise

Post by Sietedj » Sat Mar 05, 2016 6:18 pm

pjeva wrote:Put some torroid inductor (from old PC power supply for example) or any RF choke you can find, on + wire of fan supply. It should do the trick, and you must raise input voltage on 7812 at 15v. Othervise it would not work properly.


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Thank you, I'll have it in mind. How this is not the definitive transmitter wait to have the other to see if they make noise or not. I'm trying to one Chinese and is not the best way because I use the microphone input to work my stereo encoder. Possibly this he entered not be best for these tests.

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