Return-Path: Received: from [24.25.9.100] (HELO ms-smtp-01-eri0.southeast.rr.com) by logan.com (CommuniGate Pro SMTP 4.1.8) with ESMTP id 3075910 for flyrotary@lancaironline.net; Fri, 12 Mar 2004 11:56:34 -0500 Received: from edward (clt78-020.carolina.rr.com [24.93.78.20]) by ms-smtp-01-eri0.southeast.rr.com (8.12.10/8.12.7) with SMTP id i2CGuUSn027765 for ; Fri, 12 Mar 2004 11:56:32 -0500 (EST) Message-ID: <002701c40852$b104aa70$2402a8c0@edward> From: "Ed Anderson" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Re: charging Date: Fri, 12 Mar 2004 11:54:31 -0500 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0024_01C40828.C7AE00C0" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2800.1158 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1165 X-Virus-Scanned: Symantec AntiVirus Scan Engine This is a multi-part message in MIME format. ------=_NextPart_000_0024_01C40828.C7AE00C0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable ----- Original Message -----=20 From: Steve Brooks=20 To: Rotary motors in aircraft=20 Sent: Friday, March 12, 2004 11:25 AM Subject: [FlyRotary] Re: charging John, I used a relay on mine. I saw a schematic somewhere, or read that the = best to do was to use the alt warning lead from the alternator to pull a = relay. I then used a normally open contact on the relay to provide = 12VDC to an LED on the I/P through a 680 ohm resistor. =20 Mine seems to work fine.=20 =20 Steve Brooks Cozy MKIV #1071 CH 25-finishing =20 -----Original Message----- From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net]On = Behalf Of John Slade Sent: Friday, March 12, 2004 8:10 AM To: Rotary motors in aircraft Subject: [FlyRotary] charging =20 I'm still having trouble with my alternator warning light.=20 I know we discussed this before, but would someone refresh my mind?=20 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 John, Not certain about your setup, but as Steve indicated its probably = best not to have a LED in series with the lamp or idiot light wiring = into the alternator. It appears that the Mazda Alternator uses the = current through that line to bootstrap the field coils and start the = alternator producing electricity. After the alternator starts producing = then it no longer needs the voltage from that wire. =20 In the car circuit a relay and diode are in that line and as Steve = said using the points of the relay to control the voltage to your lamp = (type probably doesn't matter LED or incandescent). If you have a lamp or LED or lamp in that line and should it fail - = then no startup voltage will be supplied to your field coils on start = up and no voltage from the alternator. It will appear that your = alternator has failed and normally no voltage would be produced by the = alternator. The probably reason your LED stays lit is you do not have the diode = in the circuit. With the diode there it would be back-biased by the = voltage from the alternator. If back-biased, then the diode cuts off = ALL current flow and the light will not stay lit. I suspect that = without the diode there is still sufficient current flow after the = alternator starts to cause a voltage drop a cross your LED sufficient to = keep it lit. I would recommend using the circuit that has a 12V relay and a 16 volt = diode in series. You can get both from most Radio Shack stores (or used = to be able to). The base (sharp point of the diode symbol) should point = toward the alternator and away from the battery voltage. This results = in 12Volts of forward-bias across the diode. That way when the = alternator is not producing voltage (say at start up), the diode is = biased so that current flows through it and therefore the relay causing = the relay to close which in turn lights on your lamp/LED (and also = provides the bootstrap voltage to your alternator's field coil). Once = the alternator starts producing voltage, the voltage on the alternator = side of the diode starts to increase, when that voltage approaches the = 12Volts on the other (battery) side of the diode the voltage difference = across the diode approaches zero (12V on battery side minus 12Volt on = alternator side of diode =3D zero) the diode stops conducing current . = When the diode stops conducting , the current flow through it and the = relay stops. The relay no longer can stay closed so the points open and = your lamp goes out indicating the alternator is functioning. Again, if your alternator is similar to the Mazda alternator set up. A = failed bulb in that line can fail and your alternator may not produce = voltage. Using the LED without the diode probably permits sufficient = current to flow even after alternator startup to keep the LED lit. If = you just want to make the light go out then inserting the diode as I = mention would do that - but, I strongly recommend not have a lamp in the = direct line but use a relay to interface to the lamp. My 0.02 worth. Ed Anderson ------=_NextPart_000_0024_01C40828.C7AE00C0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
 
----- Original Message -----
From:=20 Steve = Brooks
Sent: Friday, March 12, 2004 = 11:25=20 AM
Subject: [FlyRotary] Re: = charging

John,

I used=20 a relay on mine.  I saw = a=20 schematic somewhere, or read that the best to do was to use the alt = warning=20 lead from the alternator to pull a relay.  I then used a normally open = contact on=20 the relay to provide 12VDC to an LED on the I/P through a 680 ohm=20 resistor.

 

Mine=20 seems to work fine.

 

Steve=20 Brooks

Cozy=20 MKIV #1071

CH=20 25-finishing

 

-----Original=20 Message-----
From: = Rotary=20 motors in aircraft [mailto:flyrotary@lancaironline.net]On Behalf Of John = Slade
Sent: Friday, March 12, 2004 = 8:10=20 AM
To: Rotary = motors in=20 aircraft
Subject: = [FlyRotary]=20 charging

 

I'm=20 still having trouble with my alternator warning light.=20

I know=20 we discussed this before, but would someone refresh my mind?=20

Currently I = have an=20 LED in the circuit as the warning light. It doesn't go out. Buss = voltage seems=20 fairly stable at 14.2v with engine running. Do I need a regular bulb = rather an=20 LED, and what are the specs of the diode shown in the=20 schematic?

John=20 Slade (hit 25 mph last night)

 

 John,

 

    Not certain about your setup, but as = Steve =20 indicated its probably  best not to have a LED in series with the = lamp or=20 idiot light wiring into the alternator.  It appears that the = Mazda=20 Alternator uses the current through that line to bootstrap the field = coils and=20 start the alternator producing electricity.  After the alternator = starts=20 producing then it no longer needs the voltage from that wire. =20

 

In the car circuit a relay = and diode are=20 in that line and as Steve said using the points of the relay to = control the=20 voltage to your lamp (type probably doesn't matter LED or=20 incandescent).

If you have a lamp or LED or = lamp in that=20 line and should it fail - then no startup voltage will  be = supplied to=20 your field coils on start up and no voltage from the alternator.  = It will=20 appear that your alternator has failed and normally no voltage would = be=20 produced by the alternator.

 

The probably reason your LED=20 stays lit  is you do not have the diode in the = circuit.  With=20 the diode there it would be back-biased by the voltage from the=20 alternator.  If back-biased, then the diode cuts off ALL current = flow and=20 the light will not stay lit.  I suspect that without the diode = there is=20 still sufficient current flow after the alternator starts to cause a = voltage=20 drop a cross your LED sufficient to keep it lit.

 

I would recommend using the = circuit that=20 has a 12V relay and a 16 volt diode in series.  You can get both = from=20 most Radio Shack stores (or used to be able to).  The base (sharp = point=20 of the diode symbol) should point toward the alternator = and away=20 from the battery voltage.  This results in 12Volts of=20 forward-bias across the diode.  That way when the alternator = is not=20 producing voltage (say at start up), the diode is biased so that = current flows=20 through it and therefore the relay causing the relay to close which in = turn=20 lights on your lamp/LED (and also provides the bootstrap voltage = to your=20 alternator's field coil).  Once the alternator starts=20 producing voltage, the voltage on the alternator side of the = diode=20 starts to increase, when that voltage approaches the 12Volts on the = other=20 (battery) side of the diode the voltage difference across the diode = approaches=20 zero (12V on battery side minus 12Volt on alternator side of = diode =3D=20 zero) the diode stops conducing current .  When the diode = stops=20 conducting , the current flow through it and the relay stops.  = The relay=20 no longer can stay closed so the points open and your lamp goes out = indicating=20 the alternator is functioning.

 

Again, if your alternator is = similar to=20 the Mazda alternator set up. A failed bulb in that line can fail and = your=20 alternator may not produce voltage.  Using the LED without the = diode=20 probably permits sufficient current to flow even after alternator = startup to=20 keep the LED lit. If you just want to make the light go out then = inserting the=20 diode as I mention would do that - but, I strongly recommend not have = a lamp=20 in the direct line but use a relay to interface to the = lamp.

 

 

My 0.02 = worth.

 

Ed Anderson

 

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