Alternator problem

Rustbucket68 Seriously Crusin Dubber

136 posts · joined Jun 2003 · 24 Jul 2006, 6:47 pm

#514964

Could anyone help diagnose this problem. We have a 76 beetle and the charging light is not going out until above 3500 RPM's . It used to go out about 1000 RPM's. The multimeter reads 11.75v when the light is on and 12.95 when the light is off. Any ideas ?

barls Administrator Causer of Chaos and Mayhem

9,473 posts · joined Jun 2004 · 24 Jul 2006, 6:50 pm

#514968

how are the bushes in the unit.

“We all pay for life with death, so everything in between should be free.” Bill Hicks
the chaos project - click me

Rustbucket68 Seriously Crusin Dubber

136 posts · joined Jun 2003 · 24 Jul 2006, 6:54 pm

#514971

It was rebuilt 6 months ago so they should be ok but havent checked yet.

aussiebaja Insano Dub Head

738 posts · joined Jun 2006 · 24 Jul 2006, 7:23 pm

#514978

is the wiring right on the back of the alt,no half broken wires

Bizarre Moderator The artist formerly known as blue74l

12,785 posts · joined Aug 2002 · 24 Jul 2006, 7:27 pm

#514981

Can we clear a couple of things

You say alternator problems and 1976 beetle.

A 1976 beetle "should" have an internal regulator alternator.

Brushes are on generators

If you have a internal reg beetle i think you will need to swap units as there isnt anything you can do.

Futue te ipsum!!!

68AutoBug Beetle Restorer - Experience over 138\% - YIKES --

11,654 posts · joined Aug 2002 · 24 Jul 2006, 8:45 pm

#515018

Hi,
Internal or external Regulator Alternators both have brushes....
The external regulator is the weak part if You have one of those type of Alternators...

The internal Regulator Alternators have [usually] only two connections...
One heavy wire for the power to go to the Battery...
and the small lead to go to the bulb in the dash/speedometer....
The light bulb is needed to excite the alternator into producing electricity....
My Volt meter in My dash reads around 14 volts most of the time I'm driving....
under 13 volts means You have a problem....
The light bulb in the dash should go out as soon as You rev the engine or sooner...

It sounds like Your Alternator needs an overhaul at an auto electrician... get a quote first...
If its brushes or diodes , it shouldn't be expensive...
but if a field coil etc has burnt out it will cost more...

with the voltages You quoted, something isn't working correctly....
Its usually only brushes or diodes or the regulator that may give trouble.....

Best of Luck

Lee

http://community.webshots.com/user/vw68autobug

- Helping keep Air Cooled VWs on the road - location: SCONE in the Upper Hunter Valley - Northern NSW 320 kms NNW of SYDNEY---

Bizarre Moderator The artist formerly known as blue74l

12,785 posts · joined Aug 2002 · 24 Jul 2006, 9:24 pm

#515036

68AutoBug wrote:Hi,Internal or external Regulator Alternators both have brushes....

Really??

never seen any brushes on my alternators.

[ Edited on 24-7-2006 by Bizarre ]

Futue te ipsum!!!

Bizarre Moderator The artist formerly known as blue74l

12,785 posts · joined Aug 2002 · 24 Jul 2006, 9:28 pm

#515041

Hmmmm............. gunna have to pull an alternator apart one day and have a good look.

"There are two bearings, one at each end, and two brushes which ride on "slip rings"; on the spinning part. There should be a brush-block on the side or top which may be removable so you could see the state of the brushes (the old style generator brushes are replacable in the car, but I haven't had a REAL close look at the alternator). Alternator brushes wear much slower that generator brushes, so it may just have a slow deterioration of these. If they are worn, also check that the slip rings aren't too worn down into "valleys" where the brushes ride. If this happens the alternator would definitely need to go to an overhaul place to have the rings machined or replaced so new brushes will ride properly."

Damn that Rob and dave is a good site :blush

Futue te ipsum!!!

barls Administrator Causer of Chaos and Mayhem

9,473 posts · joined Jun 2004 · 24 Jul 2006, 9:29 pm

#515043

how do you think they get the power out of the rotating machinery other than a slip ring

“We all pay for life with death, so everything in between should be free.” Bill Hicks
the chaos project - click me

Bizarre Moderator The artist formerly known as blue74l

12,785 posts · joined Aug 2002 · 25 Jul 2006, 8:05 am

#515132

I thought it was just induced fields

Like how a motor can generate - no brushes there

Futue te ipsum!!!

MickH Hairy Gutted Sloth

3,389 posts · joined Sep 2003 · 25 Jul 2006, 8:24 am

#515141

Bizarre wrote:
68AutoBug wrote:Hi,Internal or external Regulator Alternators both have brushes....
Really??

never seen any brushes on my alternators.

[ Edited on 24-7-2006 by Bizarre ]

Have another look....

tssnq.com.au

blutopless2 DAMSLO

2,457 posts · joined Jan 2004 · 25 Jul 2006, 8:27 am

#515143

they are there.

see.... air and water do mix 😉

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