TheSamba.com :: View topic - A 6 volt generator/regulator wiring question

Wed Mar 16, 2005 3:54 pm

DF has one wire and D+ has two? That's how my generator was wired to my voltage regulator. Attempting to test the generator by grounding DF to generator housing, and testing volts from D+ to generator housing, with regulator disconnested from both. I am doing this because my gen light stays on. Became concerned because I was getting no reading with idle.. Did continuity checks and DF to one of my D+ wires made my multimeter beep, but DF to the other D+ did not. I would assume either one of those D+ is really a DF, or it is shorted, or grounded. Anyone know what I'm talking about? Next is the attempt to polarize the generator, but wanted to do this test correctly first.

Wed Mar 16, 2005 6:09 pm

OK, so went ahead and polarized the gen. Had to touch my pos. batt. lead to both D+ wires to make it spin. Reconnected the belt, cranked it over, but was only reading 0.1 volts on D+ to generator ground. Any ideas? Suggestions?

Wed Mar 16, 2005 9:42 pm

Is this a stock 6V generator with the regulator mounted on the gen, or is the regulator mounted separately? Converted to 12V gen?

DF just goes to the regulator DF terminal, wherever the regulator is.
D+ goes to the regulator D+ terminal, which also goes to the battery, usually at the starter solenoid big terminal. The main feed wire to the fuse block up front could also connect to D+ (or to the battery terminal on the starter solenoid.) Just depends on who's messed with the original wiring. Original 64 harness should have 2 red wires on D+, one to starter solenoid/battery and the other goes up front to the fuse block.

L-jetronic wrote: Attempting to test the generator by grounding DF to generator housing, and testing volts from D+ to generator housing, with regulator disconnected from both. .
And the result was? With belt on, DF grounded, D+ wires disconnected and engine running, voltage should be up to 18V for a 6V gen, or up to 35V for a 12V gen. No voltage, gen is dead or not grounded correctly.

L-jetronic wrote: OK, so went ahead and polarized the gen. Had to touch my pos. batt. lead to both D+ wires to make it spin. With belt off, DF grounded, D+ wires should be disconnected, connect battery to D+ on the gen and it should spin. No spin, gen is dead or not grounded correctly.

Here are 2 excellent sources for troubleshooting charging problems, good luck!

Thanks to Speedy Jim! ...
How do I test my generator?
http://www.nls.net/mp/volks/htm/gen.htm

And thanks to Rob & Dave at aussiebug! ...
Fault Finding the VW Electrical Charging System
http://www.geocities.com/aussiebug1970/generator.html

Thu Mar 17, 2005 8:45 am

And the result was...CRAP!! Generator output is 0.78 volts. This was after successfully polarizing for 5 seconds. Pulled generator, gave it a good cleaning, repolarized, even trickle charged my battery while I was neck deep in the engine compartment.
Stock 6 volt. Regulator on top. Both the gen and reg are only 12 months old.
Speedy Jim and the Aussie site are awesome and were both very useful and informative.

Thu Mar 17, 2005 9:44 am

I know the Bosch GR11X rebuilt gens are spendy. Are there any local gen rebuilders in San Diego? There are a couple here in Sac. and I've usually had good luck dealing with somebody local. It's easy to check for an open or shorted field winding but you really need a growler to check the armature. Have you ever disassembled a generator? It's pretty easy with the pulleys off. There should be instructions in your Bentley manual.

From a non-VW site... but the info is good. :-)
Quote: Armature: The armature is the heart of the generator. In order to thoroughly test it, a growler is required. A growler is used to detect shorts in the windings. The growler generates current in the armature by creating alternating electromagnetic fields around it. These fields simulate those developed by the field coils during actual operation when the armature is spinning inside the generator body. If you do not have a growler I recommend taking your armature to good Starter/Alternator/Generator shop for testing. However a couple basic checks can be performed with a good multimeter;
Check for Grounds: Set your meter to check continuity or resistance, then touch one lead to the shaft the other to one of the commutator bars. It should show infinite or open. Check each commutator bar all the way around the same way. Little or no resistance indicates a grounded coil or commutator bar.
Check for Opens: Take your leads and touch them to two different commutator bars. You should show good continuity or .5 - 2 ohms. Check bar to bar all the way around. If you show no continuity or very high resistance, there is probably an open in one or more of the windings.

Good luck!
-Dave

Thu Mar 17, 2005 10:25 am

on convoy court is a place that rebuilds them. it is just of conovy before the dump/recycle area. i have 12 volt generaters but no reg. if you want to upgrade.

Thu Mar 17, 2005 8:56 pm

So I thought I'd be driving home on battery only, so I hooked my multimeter to the +&- terminals, to be ready for breakdown. Well I start driving, and the volts are going up! I look and the GEN light is off. When I reached my top speed of 60mph (throttle cable out of adjust 'cause had to remove carb to get gen) volts was 7 even. Not sure what that is RPM-wise, but the light is out, and I'm guessing it just needed some road time to build a field after I polarized it. Will test gen voltage output sometime this weekend and post results. Great info on the armature, although I'd need to read it about ten times to digest it. We used to call those growlers "meggers".
Thanx for the replies,
Dave

Wed May 25, 2011 3:00 pm

I know this was 7 years ago, but I'm having the same trouble. My biggest problem is determining which wires coming out of the gen are D+ and DF since they are unmarked.

Fri May 08, 2015 2:09 pm

Tom Scot wrote: I know this was 7 years ago, but I'm having the same trouble. My biggest problem is determining which wires coming out of the gen are D+ and DF since they are unmarked.

i'm having same problem what is D+ and what DF...?