X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Mon, 29 Apr 2013 01:13:42 -0400 Message-ID: X-Original-Return-Path: Received: from elasmtp-kukur.atl.sa.earthlink.net ([209.86.89.65] verified) by logan.com (CommuniGate Pro SMTP 6.0.4) with ESMTP id 6230405 for lml@lancaironline.net; Sun, 28 Apr 2013 10:42:44 -0400 Received-SPF: none receiver=logan.com; client-ip=209.86.89.65; envelope-from=panelmaker@earthlink.net DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=dk20050327; d=earthlink.net; b=VukUIv0nlut8WbqFySqG6RFx78O3U+s1T1PScjhubOGJJLCYB1BXcSuoBXxlGala; h=Received:From:To:References:Subject:Date:Message-ID:MIME-Version:Content-Type:X-Mailer:In-Reply-To:Thread-Index:X-MimeOLE:X-ELNK-Trace:X-Originating-IP; Received: from [209.173.71.64] (helo=COMPUTER1) by elasmtp-kukur.atl.sa.earthlink.net with esmtpa (Exim 4.67) (envelope-from ) id 1UWSnp-0005FQ-0U for lml@lancaironline.net; Sun, 28 Apr 2013 10:42:09 -0400 From: "Jim Nordin" X-Original-To: "'Lancair Mailing List'" References: Subject: Circuit Breakers vs. fuses X-Original-Date: Sun, 28 Apr 2013 09:42:16 -0500 X-Original-Message-ID: MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0019_01CE43F4.ABCD1AF0" X-Mailer: Microsoft Office Outlook 11 In-Reply-To: Thread-Index: Ac5EEvfuSJT8gQI+QIqaF0V7UgWRbwAB1Iog X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.6157 X-ELNK-Trace: bdfc62829fd2a80cc8ad50643b1069f8239a348a220c26092e63f098af4853731b52a94febad1bfa667c3043c0873f7e350badd9bab72f9c350badd9bab72f9c X-Originating-IP: 209.173.71.64 This is a multi-part message in MIME format. ------=_NextPart_000_0019_01CE43F4.ABCD1AF0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Hey Tom, Out of reach? Why would you have them out of reach? Would that be poor design? Not really. It sounds like your only concern is not whether to use breakers or fuses from a performance perspective but that the fuses would be out of reach. Once a breaker "pops/breaks" in the air, should the pilot know something is wrong and perhaps shouldn't push the breaker again only to make it do its job again? Once maybe. If a fuse blows should you replace it in flight? Maybe - once. Fuses weight much less. Cost much less. Cost/performance goes to the fuse. Do the same job with caveats. Both are overload protectors. CBs do a better job when the load is widely variable. They are comparatively complex - an electromechanical device. They can be designed to trip quickly - quicker than fuses. When the load is constant from start to finish, on to off, fuses may be a better choice. If a breaker fails, the cost (physical replacement and cost replacement) is enormous compared to a fuse. Aircraft interiors experience extreme variables in temperature, humidity and mechanical vibration degrading breakers. Fuses win out there. Investigate the options ad infinitum. Pay your money and take your chances. Jim _____ From: Lancair Mailing List [mailto:lml@lancaironline.net] On Behalf Of Tom & Beth Sullivan Sent: Sunday, April 28, 2013 8:19 AM To: lml@lancaironline.net Subject: [LML] Circuit Breakers vs. fuses Returning from Sun & Fun a few weeks ago, I had stopped in Asheville NC to pick up my wife and see my dad. It had rained really hard while I was in Lakeland and I suspect some water penetrated the TKS panels on the wings (Mooney Rocket). Flew back to the U.P. of MI non-stop at FL 180 until about Lake Michigan where I needed FL 220 to stay out of clouds and significant icing. (N1017L for those Flight Aware addicts). About 10 minutes before penetrating the precip I turned the TKS on to high mode and after a couple minutes, no fluid? Looked at the control panel and no lights; looked at the circuit breaker and it had popped. I tried it again and it popped after about 30 seconds. Oh crap! Reset breaker and tried de-ice on low mode, and it ran fine. Luckily it ran enough fluid to keep the ice off through the 30 minute decent. When I was a couple minutes from breaking out (based on my home bas KIMT AWOS report), I tried high mode again and it worked fine. As noted above, I suspect a bit of water in the panels had froze up in the flight levels, and the "low" TKS power setting must have done the trick. Now, what if I had "fuses" located out of reach?? Will be wiring up the IVPT soon and using breakers. It is still up to the operator to use enough common sense to keep a breaker system safe. Tom ------=_NextPart_000_0019_01CE43F4.ABCD1AF0 Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable

Hey Tom,

Out of reach? Why would you have = them out of reach? Would that be poor design? Not really.

It sounds like your only concern is = not whether to use breakers or fuses from a performance perspective but that the = fuses would be out of reach.

Once a breaker = “pops/breaks” in the air, should the pilot know something is wrong and perhaps = shouldn’t push the breaker again only to make it do its job again? Once maybe. If = a fuse blows should you replace it in flight? Maybe – = once.

Fuses weight much less. Cost much = less. Cost/performance goes to the fuse. Do the same job with caveats. Both = are overload protectors.

CBs do a better job when the load is = widely variable. They are comparatively complex – an electromechanical = device. They can be designed to trip quickly – quicker than fuses. When the = load is constant from start to finish, on to off, fuses may be a better choice. = If a breaker fails, the cost (physical replacement and cost replacement) is = enormous compared to a fuse.

Aircraft interiors experience = extreme variables in temperature, humidity and mechanical vibration degrading = breakers. Fuses win out there.

Investigate the options ad = infinitum. Pay your money and take your chances.

Jim

 

From: = Lancair Mailing List [mailto:lml@lancaironline.net] On Behalf Of Tom & Beth Sullivan
Sent: Sunday, April 28, = 2013 8:19 AM
To: = lml@lancaironline.net
Subject: [LML] Circuit = Breakers vs. fuses

 

   Returning from Sun & Fun a few weeks = ago, I had stopped in Asheville NC to pick up my wife and see my dad.  It = had rained really hard while I was in Lakeland and I suspect some water penetrated the TKS panels on the wings (Mooney Rocket).  Flew back = to the U.P. of MI non-stop at FL 180 until about Lake Michigan where I needed = FL 220 to stay out of clouds and significant icing.  (N1017L for those = Flight Aware addicts).

 

   About 10 minutes before penetrating the = precip I turned the TKS on to high mode and after a couple minutes, no = fluid?  Looked at the control panel and no lights; looked at the circuit breaker = and it had popped.  I tried it again and it popped after about 30 = seconds.  Oh crap!  Reset breaker and tried de-ice on low mode, and it = ran fine.  Luckily it ran enough fluid to keep the ice off through the = 30 minute decent.  When I was a couple minutes from breaking out = (based on my home bas KIMT AWOS report), I tried high mode again and = it worked fine.  As noted above, I suspect a bit of water in the = panels had froze up in the flight levels, and the "low" TKS power setting = must have done the trick.

 

Now, what if I had "fuses" located out of = reach??

 

Will be wiring up the IVPT soon and using = breakers.  It is still up to the operator to use enough common sense to keep a breaker = system safe.

 

Tom

 

 

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