X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Mon, 12 Oct 2009 19:22:38 -0400 Message-ID: X-Original-Return-Path: Received: from smtp-auth-02.mx.pitdc1.expedient.net ([206.210.66.135] verified) by logan.com (CommuniGate Pro SMTP 5.2.16) with ESMTPS id 3882627 for lml@lancaironline.net; Sun, 11 Oct 2009 18:57:17 -0400 Received-SPF: none receiver=logan.com; client-ip=206.210.66.135; envelope-from=rpastusek@htii.com Received: from HTBOB001 (static-72-66-86-7.washdc.fios.verizon.net [72.66.86.7]) by smtp-auth-02.mx.pitdc1.expedient.net (Postfix) with ESMTPA id 0BE3B8119 for ; Sun, 11 Oct 2009 18:56:44 -0400 (EDT) From: "Robert Pastusek" X-Original-To: "'Lancair Mailing List'" References: In-Reply-To: Subject: RE: [LML] Diodes vs. Bi-Directional Zeners (SnapJacks) on Contactor Coils X-Original-Date: Sun, 11 Oct 2009 18:56:43 -0400 X-Original-Message-ID: <034801ca4ac6$1a6977a0$4f3c66e0$@com> MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0349_01CA4AA4.9357D7A0" X-Mailer: Microsoft Office Outlook 12.0 Thread-Index: AcpKoxN00kZxcD+SRZeHl8YR3WbffwAIdHQQ Content-Language: en-us This is a multi-part message in MIME format. ------=_NextPart_000_0349_01CA4AA4.9357D7A0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Mike Easley wrote: I came across some literature from Tyco on what they call "back EMF suppression", basically the reason everybody installs diodes on their contactor coils. After reading a bunch of literature, it appears that the diodes protect the switches on panel, but severely degrade the speed that the high amperage contacts separate. That's bad, since it increases the wear on the contacts significantly. I remembered that Eric at Perihelion Design sold Snapjacks that are supposed to be superior to diodes. They're Bi-Directional Zener Transient Voltage Suppressors, what a mouthfull. That is exactly what the Tyco literature explained. Eric only lists a SnapJack kit for 12V airplanes. I need 24V and I only need a few SnapJacks. So I decided to track down what Eric is using in his SnapJacks. By tracking Eric's part #P6KE18CA, they also manufacture a P6KE36CA that increases the voltage to what I need for my customer. I figured Eric had a 50% headroom 12-18V for his Snapjacks, so I should go with 36V. Mike, I ordered a 24v "kit" from Eric and installed these on my IV-P. As far as I can tell, they are at least as good as elephant repellant.no electrical problems/failures of any components in 350+ hours/18 months of flying. I say "elephant repellant" because this is probably pretty early in the life of my electrical system to be making rash claims, but so far, they have been worth the investment. Easy to install as well.. Bob ------=_NextPart_000_0349_01CA4AA4.9357D7A0 Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable

Mike Easley wrote: I came across some literature from = Tyco on what they call "back EMF suppression", basically the reason everybody installs diodes on their contactor = coils.  After reading a bunch of literature, it appears that the diodes protect the = switches on panel, but severely degrade the speed that the high amperage contacts separate.  That's bad, since it increases the wear on the contacts significantly.  I remembered that Eric at Perihelion Design sold = Snapjacks that = are supposed to be superior to diodes.  They're Bi-Directional Zener = Transient Voltage Suppressors, what a mouthfull.  That is exactly what the = Tyco literature explained.

 

Eric only lists a SnapJack kit for 12V airplanes.  I need 24V and I only need a few SnapJacks.  = So I decided to track down what Eric is using in his SnapJacks.  By = tracking Eric's part #P6KE18CA, they also manufacture a P6KE36CA that increases the voltage to what I need for my = customer.  I figured Eric had a 50% headroom 12-18V for his Snapjacks, so I should go with = 36V.

 

Mike,

 

I ordered a 24v “kit” from Eric and installed = these on my IV-P. As far as I can tell, they are at least as good as elephant = repellant…no electrical problems/failures of any components in 350+ hours/18 months = of flying. I say “elephant repellant” because this is probably = pretty early in the life of my electrical system to be making rash claims, but = so far, they have been worth the investment. Easy to install as = well..

 

Bob

 

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