X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Mon, 07 May 2012 12:45:34 -0400 Message-ID: X-Original-Return-Path: Received: from imr-mb02.mx.aol.com ([64.12.207.163] verified) by logan.com (CommuniGate Pro SMTP 5.4.5) with ESMTP id 5525771 for lml@lancaironline.net; Mon, 07 May 2012 09:06:29 -0400 Received-SPF: pass receiver=logan.com; client-ip=64.12.207.163; envelope-from=Sky2high@aol.com Received: from mtaomg-mb02.r1000.mx.aol.com (mtaomg-mb02.r1000.mx.aol.com [172.29.41.73]) by imr-mb02.mx.aol.com (8.14.1/8.14.1) with ESMTP id q47D5mwn027085 for ; Mon, 7 May 2012 09:05:49 -0400 Received: from core-mtc005c.r1000.mail.aol.com (core-mtc005.r1000.mail.aol.com [172.29.235.17]) by mtaomg-mb02.r1000.mx.aol.com (OMAG/Core Interface) with ESMTP id 707B2E000087 for ; Mon, 7 May 2012 09:05:49 -0400 (EDT) From: Sky2high@aol.com X-Original-Message-ID: <205f1.6251c658.3cd922ad@aol.com> X-Original-Date: Mon, 7 May 2012 09:05:49 -0400 (EDT) Subject: Re: [LML] Contactor test X-Original-To: lml@lancaironline.net MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="part1_205f1.6251c658.3cd922ad_boundary" X-Mailer: AOL 9.6 sub 168 X-Originating-IP: [67.175.156.123] x-aol-global-disposition: G X-AOL-SCOLL-SCORE: 1:2:462616864:93952408 X-AOL-SCOLL-URL_COUNT: 9 x-aol-sid: 3039ac1d29494fa7c8ad4866 --part1_205f1.6251c658.3cd922ad_boundary Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Content-Language: en Bill, =20 There have been numerous problems with intermittent relays. I have copied= =20 just one email on that topic: =20 Mailing List lml@lancaironline.net Archived Message #26236 =20 (http://mail.lancaironline.net:81/lists/lml/Message/26235.html?Language=3D)= =20 (http://mail.lancaironline.net:81/lists/lml/Message/26237.html?Language=3D)= _back to=20 list_ (http://mail.lancaironline.net:81/lists/lml/List.html?Language=3D)=20 From: Sky2high@aol.com Sender: "Marvin Kaye" =20 Subject: Re: [LML] Landing Gear Relays Date: Thu, 21 Oct 2004 11:24:06 -04= 00 =20 To: lml@lancaironline.net =20 (http://mail.lancaironline.net:81/lists/lml/Message/26236-H.txt)=20 (http://mail.lancaironline.net:81/lists/lml/Message/26236-P.txt) =20 =20 In a message dated 10/21/2004 8:16:32 AM Central Standard Time, =20 ChasNelson@aol.com writes: I own a Lancair 360 with the more recent electrohydraulic power packs. I= =20 believe one of my landing gear relays have gone bad. Does anyone know the= =20 source of this component? Symptoms: Pump does not come on and low pressure side is not pressurized.= =20 Voltmeter measurements: 12V at low pressure switch, 12V at low pressure=20 relay control post, 12 V at high current input to low pressure relay, 0 vo= lts =20 at high current output, Relay is hot. The gear retract fine. Try: _http://www.aerocraftparts.com/ItemForm.aspx?item=3D5481-001_=20 (http://www.aerocraftparts.com/ItemForm.aspx?item=3D5481-001)=20 You may have wired the circuitry per Lancair's directions and that can=20 lead to this problem 1. With the down circuit engaged (gear down sw), the gear motor breaker=20 open and the hydro pressure low enough, the master switch was turned on fo= r a=20 long time. 2. The relay power fuse or breaker was not open. 3. Thus, the down relay was powered but there was no panel indication from= =20 the gear in transit light since it is powered from the motor power circuit= . 4. Since it is an intermittent relay under power for a long time, it=20 overheated and, after the power was removed, the melted coil insulation go= o=20 cooled and locked the plunger in the open position. Consider this wiring: 1. the relay coil power circuit breaker or fuse should be connected after= =20 the motor breaker so that when the motor breaker is pulled all power to th= e=20 entire electro-hydraulic system is removed. 2. the indicator light circuit should be isolated by diodes so that power= =20 is not backfed to the other relay. If the diodes are small enough they=20 should blow before the small indicator wire starts a fire should it become= is=20 shorted and is asked to carry the 50/60 amps of the motor circuit.=20 Otherwise, an inline fuse would help. Scott Krueger AKA Grayhawk N92EX IO320 Aurora, IL (KARR) In a message dated 5/7/2012 6:58:06 A.M. Central Daylight Time, =20 super_chipmunk@roadrunner.com writes: =20 I took Paul Miller=E2=80=99s suggestion and tested the windings on the 50A = Leach=20 and the Lancair- supplied contactors.=20 =20 I connected a 24V power supply to the coil terminals without any load=20 across the points and after 36 hours continuous the Leach case was slightl= y=20 warm to the touch. All of the terminals checked out- electrically isolated= =20 from the case, low resistance across the points. =20 The Lancair contactor was very different. Within about 15 minutes the=20 case was too hot to hold comfortably. The winding and contact terminals =20 grounded to the case in an apparently random fashion with changing values o= f =20 resistance and voltage. When the unit cooled down the terminals were =20 electrically isolated and coil resistance was as new so the coil wasn=E2=80= =99t shorted=20 internally and the unit seemed to be fine. As power was reapplied and the = coil=20 began to warm the process repeated. =20 I haven=E2=80=99t heard of any problems on the LML so these contactors s= eem to=20 be adequate for the job. Oildyne says the pump is intermittent duty (no=20 percentage given) so it might be toasted before any problem with the conta= ctor=20 showed up. OTOH the contactor is relatively heavy and seems marginal-=20 people using them might consider something different. =E2=80=93Bill Wade --part1_205f1.6251c658.3cd922ad_boundary Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Content-Language: en
Bill,
 
There have been numerous problems with intermittent relays. = I=20 have copied just one email on that topic:
 
Mailing List lml@lancaironline.net Archived Me= ssage=20 #26236 =20 =20 back=20 to list

lml@lancaironline.net
From: Sky2high@aol.com
Sender: "Marvin Kaye"=20 <marv@lancaironline.net>
Subject: Re: [LML] Landing Gear Relays
Date: Thu, 21 Oct 2004 11:24:06 -0400
To:
3D"Message
3D"Undecoded=20
In a message dated 10/21/2004 8:16:32 AM Central Standard Time,= =20 ChasNelson@aol.com writes:
I own a Lancair 360 with the more recent electrohydra= ulic=20 power packs. I believe one of my landing gear relays have gone bad.= Does=20 anyone know the source of this component?

Symptoms: Pump doe= s not=20 come on and low pressure side is not pressurized. Voltmeter=20 measurements: 12V at low pressure switch, 12V at low pressure relay= =20 control post, 12 V at high current input to low pressure relay, 0 v= olts=20 at high current output, Relay is hot.

The gear retract=20 fine.
Try:
You may have wired the circuitry per Lancair's directions and th= at=20 can lead to this problem
1. With the down circuit engaged (gear down sw), the gear motor= =20 breaker open and the hydro pressure low enough, the master switch was= =20 turned on for a long time.
2. The relay power fuse or breaker was not open.
3. Thus, the down relay was powered but there was no panel indic= ation=20 from the gear in transit light since it is powered from the motor pow= er=20 circuit.
4. Since it is an intermittent relay under power for a long= =20 time, it overheated and, after the power was removed, the melted coil= =20 insulation goo cooled and locked the plunger in the open position.
Consider this wiring:
1. the relay coil power circuit breaker or fuse should be connec= ted=20 after the motor breaker so that when the motor breaker is pulled all = power=20 to the entire electro-hydraulic system is removed.
2. the indicator light circuit should be isolated by diodes so t= hat=20 power is not backfed to the other relay. If the diodes are small enou= gh=20 they should blow before the small indicator wire starts a fire should= it=20 become is shorted and is asked to carry the 50/60 amps of the motor= =20 circuit. Otherwise, an inline fuse would help.
Scott=20 Krueger AKA Grayhawk
N92EX IO320 Aurora, IL=20 (KARR)
 
In a message dated 5/7/2012 6:58:06 A.M. Central Daylight Time,=20 super_chipmunk@roadrunner.com writes:
=
  I took Paul Miller=E2=80=99s suggestion and tested the windin= gs on the 50A=20 Leach and the Lancair- supplied contactors.
 
  I connected a 24V power supply to the coil terminals without = any=20 load across the points and after 36 hours continuous the Leach case was= =20 slightly warm to the touch. All of the terminals checked out- electricall= y=20 isolated from the case, low resistance across the points.
 
  The Lancair contactor was very different. Within about 15 min= utes=20 the case was too hot to hold comfortably. The winding and contact termina= ls=20 grounded to the case in an apparently random fashion with changing values= of=20 resistance and voltage. When the unit cooled down the terminals were=20 electrically isolated and coil resistance was as new so the coil wasn=E2= =80=99t=20 shorted internally and the unit seemed to be fine. As power was reapplied= and=20 the coil began to warm the process repeated.
 
  I haven=E2=80=99t heard of any problems on the LML so these c= ontactors=20 seem to be adequate for the job. Oildyne says the pump is intermittent du= ty=20 (no percentage given) so it might be toasted before any problem with the= =20 contactor showed up. OTOH the contactor is relatively heavy and seems=20 marginal- people using them might consider something different.
    =E2=80=93Bill=20 Wade
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