Return-Path: <13brv3@bellsouth.net> Received: from imf19aec.mail.bellsouth.net ([205.152.59.67] verified) by logan.com (CommuniGate Pro SMTP 4.1.8) with ESMTP id 3075821 for flyrotary@lancaironline.net; Fri, 12 Mar 2004 11:02:34 -0500 Received: from rad ([68.221.180.72]) by imf19aec.mail.bellsouth.net (InterMail vM.5.01.06.08 201-253-122-130-108-20031117) with ESMTP id <20040312160233.KJGX12770.imf19aec.mail.bellsouth.net@rad> for ; Fri, 12 Mar 2004 11:02:33 -0500 From: "Russell Duffy" <13brv3@bellsouth.net> To: "'Rotary motors in aircraft'" Subject: RE: [FlyRotary] charging Date: Fri, 12 Mar 2004 10:02:13 -0600 Message-ID: <016201c4084b$62682ba0$6001a8c0@rad> MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0163_01C40819.17CDBBA0" X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook, Build 10.0.4510 Importance: Normal In-Reply-To: X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1165 This is a multi-part message in MIME format. ------=_NextPart_000_0163_01C40819.17CDBBA0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: quoted-printable Currently I have an LED in the circuit as the warning light. It doesn't = go out. Buss voltage seems fairly stable at 14.2v with engine running. Do I need a regular bulb rather an LED, and what are the specs of the diode = shown in the schematic? John Slade (hit 25 mph last night)=20 =20 =20 Hi John, =20 I would think an LED would work fine, but unfortunately, the simple schematic doesn't tell us that much. They're showing a transistor, = which should be either on, or off, like a switch. When no error exists, the transistor (switch) should be open, and your LED should be off. It's entirely possible that there's more to the circuit than we know. =20 =20 First, are you absolutely sure you are hooking your wires to the correct terminals? In the schematic, they show the L terminal above S, but on = the picture of the alt, you'll notice that L is below S. If your LED = happens to be in the S circuit, that would explain why it's on all the time.=20 =20 Second, did you deviate from the wiring diagram in any way other than = using an LED in place of a lamp and diode? Primarily, do the S and L circuits eventually tie to the same point as shown? =20 Try putting a normal diode (just about any diode from Radio Shack) = between your LED and the L terminal. I've always assumed that LED's behave the = same as normal diodes, but I can't say I've ever tested one to see. Nor have = I ever used on in place of a normal diode. =20 =20 Also, putting a resistor in series with LED's is a pretty good practice. Finn suggested 470 ohms, and I imagine that's fine. The resistor limits = the current some to protect the LED, but I doubt it's essential in this = circuit for protection. The circuit itself might expect some resistance, which = it was previously getting from the lamp, so a resistor might do more good = than just protection. This is all speculation since we don't know the rest = of the circuit. =20 Finally, (as he rambles on) try temporarily hooking a 12V lamp of some = sort with a diode to make it just like the wiring diagram. You might have an actual problem with your alternator. =20 =20 Good luck, Rusty =20 =20 =20 =20 ------=_NextPart_000_0163_01C40819.17CDBBA0 Content-Type: text/html; charset="US-ASCII" Content-Transfer-Encoding: quoted-printable Message
Currently I have = an LED in the=20 circuit as the warning light. It doesn't go out. Buss voltage seems = fairly=20 stable at 14.2v with engine running. Do I need a regular bulb rather an = LED, and=20 what are the specs of the diode shown in the=20 schematic?
John Slade=20 (hit 25 mph last night) 
 
 
Hi=20 John,
 
I would think = an LED would=20 work fine, but unfortunately, the simple schematic doesn't tell us that=20 much.  They're showing a transistor, which should be either on, or = off,=20 like a switch.  When no error exists, the transistor (switch) = should be=20 open, and your LED should be off.  It's entirely possible that = there's more=20 to the circuit than we=20 know.  
 
First, are you = absolutely=20 sure you are hooking your wires to the correct terminals?  In the=20 schematic, they show the L terminal above S, but on the picture of the=20 alt, you'll notice that L is below S.  If your LED happens to = be in=20 the S circuit, that would explain why it's on all the=20 time. 
 
Second, did = you deviate from=20 the wiring diagram in any way other than using an LED in place of a lamp = and=20 diode?  Primarily, do the S and L circuits eventually tie to the = same point=20 as shown?
 
Try putting a = normal=20 diode (just about any diode from Radio Shack) between your LED and = the L=20 terminal.  I've always assumed that LED's behave the same as normal = diodes,=20 but I can't say I've ever tested one to see.  Nor have I ever used = on in=20 place of a normal = diode.  
 
Also, putting = a resistor in=20 series with LED's is a pretty good practice.  Finn suggested 470 = ohms, and=20 I imagine that's fine.  The resistor limits the current some to = protect the=20 LED, but I doubt it's essential in this circuit for protection.  = The=20 circuit itself might expect some resistance, which it was previously = getting=20 from the lamp, so a resistor might do more good than just = protection.  This=20 is all speculation since we don't know the rest of the=20 circuit.
 
Finally, (as he rambles on) = try=20 temporarily hooking a 12V lamp of some sort with a diode to make it just = like=20 the wiring diagram.  You might have an actual problem with your=20 alternator. 
 
Good=20 luck,
Rusty  =20
 
 
 
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