[Vwdiesel] PTO driven Alt

[Dave Cook]

Well I was going to suggest the GM one wire, but I didn't realize the part about having to rev it up to work.  I even googled it to make sure I was thinking of the right thing!

 
Dave Cook


________________________________
 From: "LBaird119 at aol.com" <LBaird119 at aol.com>
To: vwdiesel at vwfans.com 
Sent: Saturday, April 7, 2012 7:45 PM
Subject: Re: [Vwdiesel] PTO driven Alt
 

In a message dated 4/7/2012 3:09:25 P.M. Pacific Daylight Time,  
tgott at hotmail.com writes:

So I  need to have the exciter wire through a switched power and then have 
the main  power cables to the lights I am running or to the battery and then 
to the  lights again on a switched power? Forgot to mention that the Rear 
PTO is for a  Hyd driven tiller which has a belt pulley on it for a v belt 
which then would  drop down to the pump. That PTO is hooked straight through 
to the crank so the  pulley is spinning the same RPM as the engine. The 
pulley is about 4-4.5 inch  diameter. I don't know what the Alt pulley is but if 
it is smaller that would  speed it up some. I know the alt light kind of 
glows a little when idling on  the car/truck. Some interesting thoughts to 
ponder. 
Travis  G




Wiring depends on the alt. a little... 
  With a GM alt (3 wire) you connect D+ switched power, through an  idiot 
light if you like (helps diagnose any problems) in your cab then the B+  goes 
to the battery or a large,  power circuit tied to the battery.   The other 
wire is your "sens" wire and should go somewhere electrically central,  in 
the scheme of resistance and load.  That's the wire it uses to tell the  alt 
to charge more or less.  You can tie it right to your power/B+ wire,  but 
voltage where you need it, will always be low.  Basically the same on  the 
Bosch alts but not sure where the third wire goes right off.  Seems  like it's 
just 2 wires, B+ and D+ (exciter/idiot light).  Single wire Delco  are easy 
to wire up but require high, initial rpm to self excite.   Otherwise you can 
run all day and have it never kick in, on a low rpm  tractor.
  Sounds like your pulley might be big enough to just bolt and  go!
   Loren
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