Return-Path: Received: from rly-md03.mx.aol.com (rly-md03.mail.aol.com [172.20.29.141]) by air-md05.mail.aol.com (v124.15) with ESMTP id MAILINMD051-8f14a3cd88013; Sat, 20 Jun 2009 08:39:44 -0400 Received: from post.thorcom.com (post.thorcom.com [193.82.116.20]) by rly-md03.mx.aol.com (v124.15) with ESMTP id MAILRELAYINMD031-8f14a3cd88013; Sat, 20 Jun 2009 08:39:30 -0400 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1MHzpu-0003mz-75 for rs_out_1@blacksheep.org; Sat, 20 Jun 2009 13:38:22 +0100 Received: from [83.244.159.144] (helo=relay3.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1MHzpt-0003mq-NJ for rsgb_lf_group@blacksheep.org; Sat, 20 Jun 2009 13:38:21 +0100 Received: from smtp5.freeserve.com ([193.252.22.128]) by relay3.thorcom.net with esmtp (Exim 4.63) (envelope-from ) id 1MHzps-00045O-5e for rsgb_lf_group@blacksheep.org; Sat, 20 Jun 2009 13:38:22 +0100 Received: from me-wanadoo.net (localhost [127.0.0.1]) by mwinf3406.me.freeserve.com (SMTP Server) with ESMTP id DD4E51C00082 for ; Sat, 20 Jun 2009 14:38:11 +0200 (CEST) Received: from AGB (unknown [91.109.53.155]) by mwinf3406.me.freeserve.com (SMTP Server) with SMTP id 354341C00081 for ; Sat, 20 Jun 2009 14:38:07 +0200 (CEST) X-ME-UUID: 20090620123807218.354341C00081@mwinf3406.me.freeserve.com Message-ID: <4D9912F553C04FB7A3C3A5DFE920F8AC@AGB> From: "Graham" To: References: <582241.74739.qm@web28516.mail.ukl.yahoo.com> In-Reply-To: <582241.74739.qm@web28516.mail.ukl.yahoo.com> Date: Sat, 20 Jun 2009 13:38:05 +0100 MIME-Version: 1.0 X-Priority: 3 X-MSMail-Priority: Normal Importance: Normal X-Mailer: Microsoft Windows Live Mail 14.0.8064.206 X-MimeOLE: Produced By Microsoft MimeOLE V14.0.8064.206 X-Spam-Score: 0.0 (/) X-Spam-Report: autolearn=disabled,HTML_MESSAGE=0.001 Subject: Re: LF: 500 kHz - Fans Content-Type: multipart/alternative; boundary="----=_NextPart_000_0046_01C9F1AC.571CE470" X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: X-Spam-Status: No, hits=0.9 required=5.0 tests=HTML_30_40,HTML_MESSAGE, MISSING_OUTLOOK_NAME autolearn=no version=2.63 X-SA-Exim-Scanned: Yes Sender: owner-rsgb_lf_group@blacksheep.org Precedence: bulk Reply-To: rsgb_lf_group@blacksheep.org X-Listname: rsgb_lf_group X-SA-Exim-Rcpt-To: rs_out_1@blacksheep.org X-SA-Exim-Scanned: No; SAEximRunCond expanded to false X-AOL-IP: 193.82.116.20 ------=_NextPart_000_0046_01C9F1AC.571CE470 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Chris..... Oh dear ....hi .... Well I would think that the fan coils my be acting as=20= antennas and subjecting the electronics control board to 'slight' over volt= age ... can you pick up a ex equipment 'ac' fan , I have a System Papst TY= P -8550-N 230V/50hz , which moves quite a bit of air , about 3 inch mount=20= , that would solve the problem ? G ..=20 From: Chris Osborn=20 Sent: Saturday, June 20, 2009 7:34 AM To: LF Group=20 Subject: LF: 500 kHz - Fans LF, I've nearly completed my new PA for 500 kHz and have now managed to stop destroying FET's. Unfortunately I have an unusual problem in that the heatsink cooling fans are going U/S. I have used 24 volts brushless PC-type fans and after a while they either die completely or start to go backwards slowly. . . The fans may be slightly over-run but only by a volt or so and on key-up=20 (unregulated supply) and are situated about 50 mm (2 inches) from the heatsi= nk. I have rf decoupled them from the supply but maybe not well enough ! Any suggestions in curing this problem would be most welcome. 73 Chris G3XIZ ----------------------------------------------------------------------------= ---- No virus found in this incoming message. Checked by AVG - www.avg.com=20 Version: 8.5.339 / Virus Database: 270.12.81/2189 - Release Date: 06/20/09 0= 6:15:00 ------=_NextPart_000_0046_01C9F1AC.571CE470 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Chris.....
 
Oh dear ....hi .... Well I would think that= the fan=20 coils my  be  acting as antennas and  subjecting the electron= ics=20 control board to 'slight' over voltage ... can you  pick up a ex=20 equipment  'ac' fan , I have a System Papst TYP -8550-N  230V/50hz= ,=20 which moves quite a bit of  air , about 3 inch mount , that would solve= =20 the  problem ?
 
G ..

Sent: Saturday, June 20, 2009 7:34 AM
Subject: LF: 500 kHz - Fans

LF,
I've nearly completed my new PA for 500 kHz and have now managed to
stop destroying FET's.
 
Unfortunately I have an unusual problem in that the heatsink cooling=20 fans
are going U/S.
 
I have used 24 volts brushless PC-type fans and after a while they
either die completely or start to go backwards slowly. . .
 
The fans may be slightly over-run but only by a volt or so and on key-u= p=20
(unregulated supply) and are situated about 50 mm (2 inches) from the=20 heatsink.
I have rf decoupled them from the supply but maybe not well enough= =20 !
 
Any suggestions in curing this problem would be most welcome.
 
73 Chris G3XIZ
 
 
 


No virus found in this incoming message.
Checked by AVG -=20 www.avg.com
Version: 8.5.339 / Virus Database: 270.12.81/2189 - Release=20 Date: 06/20/09 06:15:00
------=_NextPart_000_0046_01C9F1AC.571CE470--