Date:         Sat, 24 Apr 2010 14:14:47 -0500
Reply-To:     Tom Hargrave <thargrav@HIWAAY.NET>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Tom Hargrave <thargrav@HIWAAY.NET>
Subject:      Re: alternator installation
Comments: To: mark drillock <mdrillock@COX.NET>
In-Reply-To:  <4BD33FC6.1000105@cox.net>
Content-Type: text/plain; charset="us-ascii"

It does the exact same thing. Because they used a LED they had to shunt
across it with a resistor for the same function.

Tom
www.towercooler.com


-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@GERRY.VANAGON.COM] On Behalf Of
mark drillock
Sent: Saturday, April 24, 2010 2:00 PM
To: vanagon@GERRY.VANAGON.COM
Subject: Re: alternator installation

In a Vanagon the dash alt light led current itself does not provide the
excitation but there is a 150 ohm resistor in parallel with the alt led that
does provide a small initial startup current to trigger the alternator field
winding.

Mark


Tom Hargrave wrote:
> ..............
>
> But a alternator rotor retains so little magnetism that it usually
> takes a small amount of current to start one up. That initial current
> is supplied through your GEN dash light. Then, once the alternator
> starts up a smaller of two diode bridges inside the alternator
> provides current to the regulator. The larger diode bridge provides
> current to the car's electrical system.
>
> BTW, this is why your GEN light stays on when your alternator or
> regulator fails. The alternator rotor is no longer receiving excite
> current from the regulator and it continues to draw the small amount
> of current through your GEN light. But the current is not enough to
> drive the alternator to put out any real power.
>
>