REFLECTOR:Alternator Terminals ...

KeithHallsten reflector@tvbf.org
Sun, 19 Oct 2003 18:15:42 -0700


Jim,

I'm not an EE, but I think I can point you to the info you need.  Since you
mention crowbar OV protection, you're probably already familiar with the
AeroElectric website.  You will find the wiring diagram at
http://www.aeroelectric.com/articles/bleadov.pdf

I'm not sure why you would want to use the idiot light output from your
alternator.  What you really want is active notification of a low-voltage
condition, regardless of its cause.  There is info on the AeroElectric site
on accomplishing this.  If you need additional info, get on the AeroElectric
List on Matronics.com and post your question there.  You can sign up from a
link for "AeroElectric List (On-line Consulting)" on the AeroElectric home
page.

Keith Hallsten


----- Original Message ----- 
From: "Jim Sower" <canarder@frontiernet.net>
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>;
<aeroelectric-list@matronics.com>; <reflector@tvbf.org>
Sent: Sunday, October 19, 2003 5:32 PM
Subject: REFLECTOR:Alternator Terminals ...


>     Question for all you EEs out there.  I'm putting a new alternator on
my
> Velocity.  This one will be internally regulated (and have the appropriate
> "crowbar" OV protection.  The unit I am installing has two terminals
> arranged in a "T".  One is "field" and the other is "Indicator" (idiot
> light).  I am blessed that the builder didn't have a 20- or 22- ga wire to
> string from the "Alt"  (split Alt-Master) switch, so he used both
conductors
> of 2-wire shielded 24 ga for the 12 ft run from the switch to the
> regulator.  Anyway, I am betting that one will be enough to excite the
> regulator and I can use the other for an idiot light.
>
> Thing is, I have to determine which is which and how the "I" lead works
(is
> it hot or grounded when there is no output).  I aim to wire things up with
> jumpers and spin the alternator by hand, so to get the charging voltage at
> B+ I will need a resistor between B+ and the line back to the battery.
That
> done, I can connect stuff up and see if, when all ready to go, the "I"
lead
> is hot or grounded, and if it goes cold or breaks ground connection when I
> spin up the unit.
>
> My questions are:  Will this work (will I be able to easily twirl the
pulley
> and get charging voltage if I put the proper resistor in the circuit (so
it
> doesn't have to generate much current in order to build up charging
> voltage)?  What would be an appropriate resistance (and size) of the
> resistor I am placing in the circuit?
>
> I know I could have all this done at an alternator rebuild shop, but
there's
> none convenient to me
>
> Hope this will work.  Makes sense to me at this point .... Jim S.
>
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