X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml Date: Sat, 28 Nov 2009 12:54:50 -0500 Message-ID: X-Original-Return-Path: Received: from hrndva-omtalb.mail.rr.com ([71.74.56.124] verified) by logan.com (CommuniGate Pro SMTP 5.3c3) with ESMTP id 3993146 for lml@lancair.net; Fri, 27 Nov 2009 16:18:30 -0500 Received-SPF: none receiver=logan.com; client-ip=71.74.56.124; envelope-from=Wolfgang@MiCom.net Received: from micomxp ([74.218.201.50]) by hrndva-omta02.mail.rr.com with SMTP id <20091127211754142.KQP12643@hrndva-omta02.mail.rr.com> for ; Fri, 27 Nov 2009 21:17:54 +0000 X-Original-Message-ID: <001101ca6fa7$1504fb30$6401a8c0@micomxp> From: "Wolfgang" X-Original-To: Subject: Gear warning indicator X-Original-Date: Fri, 27 Nov 2009 16:17:53 -0500 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_000E_01CA6F7D.2BD45010" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.2180 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.2180 This is a multi-part message in MIME format. ------=_NextPart_000_000E_01CA6F7D.2BD45010 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Hmmm . . . The gear position switches provide a GROUND to the bulbs. If = one or more of the lights are lit by a gear position switch, the voltage = at that side (my diodes) of the bulb is GROUND which can not feed any = voltage back to the circuit.=20 Look again and hopefully you will see the error of your ways. Wolfgang -------------------------------------------------------------------------= ------- From: "Dan Schaefer" =20 Sender: =20 Subject: Gear warning indicator=20 Date: Fri, 27 Nov 2009 08:40:07 -0500=20 To: lml=20 =20 =20 =20 Excuse me!! This looks to have at least two design faults. Problem 1: If the airspeed switch is closed and any one (or more) = of the green "down and locked" lights are energized via the gear = position switches, 12 volts will be applied thru one or more of the = diodes to this "blinker" and it will try to operate - e.g., the 1000 = mike capacitor will charge thru the 100 ohm resistor until the voltage = reaches the relay pull-in voltage. Problem 2: Unfortunately, as soon as the capacitor charges = sufficiently to pull in the relay, the relay contacts close and the 12 = volts is shorted directly to ground. Hopefully, only blowing a fuse or = popping a breaker, but effectively taking at least the gear light = circuit down. Neat! Dan Schaefer PS: Stick the resistor on the other side of the relay contacts to = at least solve the shorting - not sure what to do to keep this thing = from blinking the lights when at least one gear leg is down and locked. = But what do I know? I'm just a retired EE and things have a way of = getting fuzzy in 10 years! DS --=20 ------=_NextPart_000_000E_01CA6F7D.2BD45010 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Hmmm . . .  The gear position switches provide a GROUND to the = bulbs.=20 If one or more of the lights are lit by a gear position switch, the = voltage at=20 that side (my diodes) of the bulb is GROUND which can not feed any = voltage back=20 to the circuit.
 
Look again and hopefully you will see the error of your ways.
 
Wolfgang

 
From: "Dan Schaefer"=20 <dfs155@roadrunner.com>
Sender: <marv@lancaironline.net>
Subject: Gear warning = indicator
Date: Fri, 27 Nov 2009 08:40:07 = -0500
To: lml

 
Excuse me!! This looks to have at least = two=20 design faults.

Problem 1: If the airspeed switch is closed = and any=20 one (or more) of the green "down and locked" lights are energized = via the=20 gear position switches, 12 volts will be applied thru one or more = of the=20 diodes to this "blinker" and it will try to operate - e.g., the = 1000 mike=20 capacitor will charge thru the 100 ohm resistor until the voltage = reaches=20 the relay pull-in voltage.

Problem 2: Unfortunately, as = soon as the=20 capacitor charges sufficiently to pull in the relay, the relay = contacts=20 close and the 12 volts is shorted directly to ground. Hopefully, = only=20 blowing a fuse or popping a breaker, but effectively taking at = least the=20 gear light circuit down.

Neat!

Dan = Schaefer

PS: Stick=20 the resistor on the other side of the relay contacts to at least = solve the=20 shorting - not sure what to do to keep this thing from blinking = the lights=20 when at least one gear leg is down and locked. But what do I know? = I'm=20 just a retired EE and things have a way of getting fuzzy in 10=20 years!

DS = --
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