Return-Path: Received: from imf25aec.mail.bellsouth.net ([205.152.59.73] verified) by logan.com (CommuniGate Pro SMTP 4.1.6) with ESMTP id 2716312 for flyrotary@lancaironline.net; Sun, 09 Nov 2003 12:37:47 -0500 Received: from TOSHIBAjhr ([209.215.55.102]) by imf25aec.mail.bellsouth.net (InterMail vM.5.01.05.27 201-253-122-126-127-20021220) with SMTP id <20031109173745.GACA1843.imf25aec.mail.bellsouth.net@TOSHIBAjhr> for ; Sun, 9 Nov 2003 12:37:45 -0500 From: "John Slade" To: "Rotary motors in aircraft" Subject: RE: [FlyRotary] Re: Murphy's law of precautionary landings Date: Sun, 9 Nov 2003 12:37:45 -0500 Message-ID: MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0002_01C3A6BE.4667CA30" X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook IMO, Build 9.0.2416 (9.0.2910.0) X-MIMEOLE: Produced By Microsoft MimeOLE V6.00.2800.1165 Importance: Normal In-Reply-To: This is a multi-part message in MIME format. ------=_NextPart_000_0002_01C3A6BE.4667CA30 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit MessageJohn, I don't follow the aero-electric list, but I did look around for the posts you mentioned. I didn't see them right off, and I can't really imagine sizing a fuse smaller than the alternator output rating. If you can find those posts in the archive, tell me what the subject line was, and I'll take a look. I had it the wrong way around. Bob Nuckolls said: The JJS/JJN series fuses are very fast acting and were deliberately oversized for alternator b-lead applications to prevent nuisance tripping. An JJS/JJN-80 fuse is fine for alternators from 35 to 60A. Given low cost availability of the ANL series limiters and in light of their VERY robust overcurrent carrying behavior, you'll want to size the limiter closer to the rated output of the alternator. ANL limiters are available in a variety of sizes which you can check out by downloading this data sheet. http://www.bussmann.com/library/bifs/2024.pdf Note these devices are designed to clear HARD faults in the hundreds of amperes . . . exactly the type of fault to be expected in the alternator b-lead circuit. ------=_NextPart_000_0002_01C3A6BE.4667CA30 Content-Type: text/html; charset="US-ASCII" Content-Transfer-Encoding: quoted-printable Message
John, I don't follow the aero-electric list, but I = did look=20 around for the posts you mentioned.  I didn't see them right off, = and I=20 can't really imagine sizing a fuse smaller than the alternator output=20 rating.  If you can find those posts in the archive, tell me what = the=20 subject line was, and I'll take a look.   
 
I had it the wrong way = around. Bob=20 Nuckolls said:
The JJS/JJN series = fuses are very=20 fast acting and were
  deliberately oversized for alternator = b-lead=20 applications
  to prevent nuisance tripping. An JJS/JJN-80 fuse=20 is
  fine for alternators from 35 to 60A.

  Given = low cost=20 availability of the ANL series limiters
  and in light of their = VERY=20 robust overcurrent carrying
  behavior, you'll want to size the = limiter=20 closer to the
  rated output of the alternator. ANL limiters are = available
  in a variety of sizes which you can check out = by
 =20 downloading this data sheet.

  http://www.bussmann.com/library/bifs/2024.pdf
=
  Note these devices are designed to clear HARD=20 faults
  in the hundreds of amperes . . . exactly the type = of
 =20 fault to be expected in the alternator b-lead=20 circuit.

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