REFLECTOR:Alternator wiring
Laurence Coen
reflector@tvbf.org
Thu, 1 May 2003 12:06:32 -0500
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Hiroo,
The "S" connection is the "Sense" or field reference. When connected to =
the buss it automatically compensates for any voltage drop in the =
alternator power wire. The "L" is the "Light" connection and is for the =
so called idiot light output. This configuration comes from the =
automotive world. On an auto the + or "Bat" terminal is connected =
directly to the battery and is not switched. When the ignition is =
turned on , power is applied to the sense lead which causes the "idiot =
light" to come on. When the engine starts and the alternator begins to =
produce power the "idiot light" goes out. The primary reason that =
aircraft have over voltage protection and cars don't is the master relay =
or solenoid. On a car the battery provides over voltage protection =
since it is always connected to the alternator. Airplanes can isolate =
the battery by turning off the master with the engine still running and =
the alternator still connected to the aircraft buss. Under these =
conditions it is likely you will get an over voltage surge and maybe =
smoke some expensive stuff on your panel if you don't have over voltage =
protection.
I hope this is helpful and doesn't simply add to the confusion.
Larry Coen
SE RG Franklin
----- Original Message -----=20
From: Hiroo Umeno=20
To: reflector@tvbf.org=20
Sent: Tuesday, April 29, 2003 3:19 PM
Subject: REFLECTOR:Alternator wiring
Here I am, still doing wiring.
My alternator I got from Franklin guys in CO got me scratching my =
head. Many of the airplane wiring references refer to three major =
connections to the alternator. Airframe GND, Alternator Field, and =
Alternator Out.
Now, as I look at my alternator, there appears to be four connections. =
One is the GND which essentially is the casing bolted down to the =
engine. Then there is a terminal that is marked with '+' symbol that I =
figured is the OUT judging from the size of the bolt and nut on the =
terminal. Now, on the side, there is a plastic connector that has two, =
yes two, wires coming out. One is yellow and the other is green. They =
are marked 'S' and 'L'. I am guessing one of them is the 'Field' but =
which one?
Has anyone got this figured out?
Hiroo
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<DIV><FONT face=3DArial size=3D2>Hiroo,</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2>The "S" connection is the "Sense" or =
field=20
reference. When connected to the buss it automatically compensates for =
any=20
voltage drop in the alternator power wire. The "L" is the "Light"=20
connection and is for the so called idiot light output. This =
configuration=20
comes from the automotive world. On an auto the + or "Bat" =
terminal is=20
connected directly to the battery and is not switched. When the =
ignition=20
is turned on , power is applied to the sense lead which causes the =
"idiot light"=20
to come on. When the engine starts and the alternator begins to =
produce=20
power the "idiot light" goes out. The primary reason that aircraft =
have=20
over voltage protection and cars don't is the master relay or =
solenoid. On=20
a car the battery provides over voltage protection since it is always =
connected=20
to the alternator. Airplanes can isolate the battery by turning =
off the=20
master with the engine still running and the alternator still connected =
to the=20
aircraft buss. Under these conditions it is likely you will get an =
over=20
voltage surge and maybe smoke some expensive stuff on your panel if you =
don't=20
have over voltage protection.</FONT></DIV>
<DIV><FONT face=3DArial size=3D2>I hope this is helpful and doesn't =
simply add to=20
the confusion.</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2>Larry Coen</FONT></DIV>
<DIV><FONT face=3DArial size=3D2>SE RG Franklin</FONT></DIV>
<BLOCKQUOTE dir=3Dltr=20
style=3D"PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; =
BORDER-LEFT: #000000 2px solid; MARGIN-RIGHT: 0px">
<DIV style=3D"FONT: 10pt arial">----- Original Message ----- </DIV>
<DIV=20
style=3D"BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: =
black"><B>From:</B>=20
<A title=3Dhumeno@microsoft.com =
href=3D"mailto:humeno@microsoft.com">Hiroo=20
Umeno</A> </DIV>
<DIV style=3D"FONT: 10pt arial"><B>To:</B> <A =
title=3Dreflector@tvbf.org=20
href=3D"mailto:reflector@tvbf.org">reflector@tvbf.org</A> </DIV>
<DIV style=3D"FONT: 10pt arial"><B>Sent:</B> Tuesday, April 29, 2003 =
3:19=20
PM</DIV>
<DIV style=3D"FONT: 10pt arial"><B>Subject:</B> REFLECTOR:Alternator=20
wiring</DIV>
<DIV><BR></DIV>
<DIV class=3DSection1>
<P class=3DMsoNormal><FONT face=3DArial size=3D2><SPAN=20
style=3D"FONT-SIZE: 10pt; FONT-FAMILY: Arial">Here I am, still doing=20
wiring=85</SPAN></FONT></P>
<P class=3DMsoNormal><FONT face=3DArial size=3D2><SPAN=20
style=3D"FONT-SIZE: 10pt; FONT-FAMILY: Arial"></SPAN></FONT> </P>
<P class=3DMsoNormal><FONT face=3DArial size=3D2><SPAN=20
style=3D"FONT-SIZE: 10pt; FONT-FAMILY: Arial">My alternator I got from =
</SPAN></FONT><FONT face=3DArial size=3D2><SPAN=20
style=3D"FONT-SIZE: 10pt; FONT-FAMILY: =
Arial">Franklin</SPAN></FONT><FONT=20
face=3DArial size=3D2><SPAN style=3D"FONT-SIZE: 10pt; FONT-FAMILY: =
Arial"> guys in=20
CO got me scratching my head. Many of the airplane wiring =
references=20
refer to three major connections to the alternator. Airframe =
GND,=20
Alternator Field, and Alternator Out.</SPAN></FONT></P>
<P class=3DMsoNormal><FONT face=3DArial size=3D2><SPAN=20
style=3D"FONT-SIZE: 10pt; FONT-FAMILY: Arial"></SPAN></FONT> </P>
<P class=3DMsoNormal><FONT face=3DArial size=3D2><SPAN=20
style=3D"FONT-SIZE: 10pt; FONT-FAMILY: Arial">Now, as I look at my =
alternator,=20
there appears to be four connections. One is the GND which =
essentially=20
is the casing bolted down to the engine. Then there is a =
terminal that=20
is marked with =91+=92 symbol that I figured is the OUT judging from =
the size of=20
the bolt and nut on the terminal. Now, on the side, there is a =
plastic=20
connector that has two, yes two, wires coming out. One is yellow =
and the=20
other is green. They are marked =91S=92 and =91L=92. I am =
guessing one of=20
them is the =91Field=92 but which one?</SPAN></FONT></P>
<P class=3DMsoNormal><FONT face=3DArial size=3D2><SPAN=20
style=3D"FONT-SIZE: 10pt; FONT-FAMILY: Arial"></SPAN></FONT> </P>
<P class=3DMsoNormal><FONT face=3DArial size=3D2><SPAN=20
style=3D"FONT-SIZE: 10pt; FONT-FAMILY: Arial">Has anyone got this =
figured=20
out?</SPAN></FONT></P>
<P class=3DMsoNormal><FONT face=3DArial size=3D2><SPAN=20
style=3D"FONT-SIZE: 10pt; FONT-FAMILY: Arial"></SPAN></FONT> </P>
<P class=3DMsoNormal><FONT face=3DArial size=3D2><SPAN=20
style=3D"FONT-SIZE: 10pt; FONT-FAMILY: =
Arial">Hiroo</SPAN></FONT></P></DIV></BLOCKQUOTE></BODY></HTML>
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