- First Gear
- Posts: 41
- Joined: 10 Jul 2004
- Location: Northern Virginia, USA
Generators simply don't have much output at low revs, which is why many owners switch to an alternator, there may be nothing wrong with your system.
The dynamo regulator ensures that there is no path from dynamo back to the battery until the dynamo is creating more than the battery voltage. This ensures that the current doesn't flow from battery to dynamo which would make your dynamo try to act as a feeble starter motor.
36/6725 S3 Coupe OGU108E Yellow over Black.
- Coveted Fifth Gear
- Posts: 4840
- Joined: 19 Apr 2008
- Location: London UK
Back in the day a skim in a lathe for the commutator, followed by under cutting the mica between the segments was the norm for repairing dynamos.
Brushes need to be a neat fit in the holders so they don't angle and jam, but free to slide,
Jon the Chief
- Third Gear
- Posts: 408
- Joined: 17 Sep 2013
- Location: Near Wolverhampton
This may help some understand actually how a dynamo works and why such an action of remagnetising would not be an issue. http://matchlessclueless.com/electrical ... as-dynamo/ It is covered part way through the article so don't assume it is just talking about re-polarisation.
However some say if you point the car direct North South and whack the exhaust with a hammer it may help but could also magnetise the chassis
Oldchieft has the best solution which may show some improvement but small comms are not always necessary to undercut unless badly worn down and often a clean up of the comm without dismantling and new brushes may again show some improvement.
We would bed new brushes into the comms when I was in the Royal Navy on large DC motors but again with small comms I dont usually bother.
Personally you may be worrying about nothing as I still have a dynamo on the Lotus and it performs about the same as what you say yours is and fitted new brushes around 5000 miles ago.
- Second Gear
- Posts: 163
- Joined: 30 Jan 2014
- Location: Uk & France
In short, your alternator was probably never designed to charge at idle engine speeds. It's cut-in is probably above that speed!
When my voltage regulator failed due to corrosion, I converted to negative earth and installed a Lucas alternator. It's one of the best changes I've made to the car. I have no hesitation in making changes to improve reliability if it doesn't change the characteristics of the driving experience hence, the alternator, tandem master brake cylinder and electric fuel pump,
'67 S3 SE FHC
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- Coveted Fifth Gear
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69 S4 SE DHC RHD Original owner
- Fourth Gear
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