[SI-LIST] Re: Audio And Fan Circuits interference
- From: "Martin Euredjian" <martin@xxxxxxxxxxxxxx>
- To: <si-list@xxxxxxxxxxxxx>
- Date: Sun, 16 Feb 2003 10:46:21 -0800
A few questions:
1- What is the power supply topology?
2- Is the fan (fans?) on the same power supply as the audio circuits?
3- Where is the fan connector (I presume) located with respect to the =
power
inpu and the audio circuitry?
4- How is the grounding handled for both the fan and audio circuits?
Moating? Plane? Discrete traces?
5- What exactly is your "fan controller"? How is it implemented?
6- Are there any capacitors right at the connector pins?
7- Have you tried extending the fan cabled by, say, three feet or more =
in
order to eliminate the magnetic coupling/near-range RFI as a =
possibility?
8- Have you tried wrapping several turns of the fan wires around a =
toroid?
9- Have you tried to connect the fan/s directly to the power source?
10- Have you measured the noise? What frequency is it? Spectrum?=20
11- Do you really need a fan? (just kidding)
But, seriously now, heat-pipe technology can be a very elegant =
solution
for the right application.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Martin Euredjian
eCinema Systems, Inc.
voice: 661-305-9320
fax: 661-775-4876
martin@xxxxxxxxxxxxxx
www.ecinemasys.com
=20
=20
=20
=20
-----Original Message-----
From: si-list-bounce@xxxxxxxxxxxxx [mailto:si-list-bounce@xxxxxxxxxxxxx] =
On
Behalf Of Brahim Koudssi
Sent: Friday, February 14, 2003 8:50 AM
To: bart.bouma@xxxxxxxxx
Cc: si-list@xxxxxxxxxxxxx; si-list-bounce@xxxxxxxxxxxxx;
jonpowell@xxxxxxxxxxxx
Subject: [SI-LIST] Re: Audio And Fan Circuits interference
Hi,
Thanks for you response.
The motor is brushless, the controller is not PWM.
Brahim
Bart Bouma wrote:
> Hi,
>
> Does the motor have brushes? If so the motor can produce a lot of EMI.
> Filtering this motor or taking a brushless one would solve your =
problem, I
> think.
>
> Another cause can be the controller circuit. Is it a PWM-controller?
>
> Bart
>
>
> "Jon Powell"
> <jonpowell@xxxxxxxxxxxx> To: =
<brahim@xxxxxxxxxxxx>
> <si-list@xxxxxxxxxxxxx>
> 13-02-03 17:45 cc:
> Sent by: Subject: [SI-LIST] =
Re:
Audio And Fan Circuits interference
> si-list-bounce@xxxxxxxxxxxxx Category:
>
>
>
> Please respond to jonpowell
>
>
>
> Does the fan circuit share VCC and GND with your audio?
> That is a common source of noise.
>
> jon
>
> -----Original Message-----
> From: si-list-bounce@xxxxxxxxxxxxx
> [mailto:si-list-bounce@xxxxxxxxxxxxx]On Behalf Of Brahim Koudssi
> Sent: Thursday, February 13, 2003 6:53 AM
> To: si-list@xxxxxxxxxxxxx
> Subject: [SI-LIST] Audio And Fan Circuits interference
>
> Hello,
>
> I have designed a board that consists of an audio circuit and a fan
> controller circuit.
> When the fan is running it induces audible noise in the audio circuit, =
I
> can hear in the speakers the fan spinning.
> Can anyone please address the following questions:
>
> 1. How's the fan audible noise getting into the audio?
> 2. How can I get rid of this interference?
>
> Thanks,
> Brahim
>
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