Re: [T3] Signs Point to Bad Generator

[Jim Adney <jadney@vwtype3.org>]

On 14 Apr 2003 at 15:01, Martinez, Leon wrote:

> The old junkyard generator is still working fine with no heat or sparks,
> What is the difference inside ? I already checked for shorts an could not 
> find any in the new one.
> 
> Anyone know what may have happened to this and other generators, any 
> experiences ?

Sparking and rapid brush wear is usually due to an out-of-round or rough 
commutator, although it could also be due to abrasive trapped in the copper 
segments due to sanding them, or (I'm guessing here) driving in dusty areas 
where the dust is abrasive.  

The problem is that copper is so soft that tiny bits of something abrasive can 
get imbedded in there and just eat away at the brushes. This is just 
speculation, however, as far as your case goes.  

Even a generator which sparks will ususlly generate. If it won't then either 
the field winding is open, or there is a short or open somewhere in the 
armature. You can measure the field winding with an ohmmeter, but it takes a 
special tool (a growler) to test the armature.  

I have also seen them where one of the leads inside the terminals area get 
slightly mis-positioned and short to ground. You want to be careful when 
connecting to these terminals that you don't twist the screw; only the nut 
should move.  

-- 
*******************************
Jim Adney, jadney@vwtype3.org
Madison, Wisconsin, USA
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