Is my generator dead?

[elutfall]

Bosch generator in a Frankenstein 1970 pan, 1973 body, standard beetle - custom 2110 engine, spaghetti for wiring.

The gen light turned on a few days ago. Belt is fine. Light goes off when I kill the ignition. Brushes look good and seem to be making contact.

Testing with a VOM at the battery shows no increase in voltage when I rev the engine. If I test for a short while, the voltage actually goes down.

Disconnecting the gen wires, jumping DF to the gen body, and hooking up the VOM to D+ and DF shows 0.23 or so volts. That makes me think it's dead.

The weird thing is I then polarized it just to cover all the bases, and it spun like a champ. Testing again still showed less than 1 volt coming out.

Used the same scale on the VOM for both the battery test and the gen test.

So is my gen kaput, or is there something else to try? If I can get that stupid 36mm bolt free, I'll take it to the parts store to see if they can test it for me.

[Cusser]

I'd test the generator again, because spinning as a motor (just do a few seconds) is contrary to your test voltage readings.

Disconnect the wires to the generator voltmeter positive on the D+ terminal of the generator, negative lead on ground, then start the engien and jumper - for just a FEW seconds - D- to ground as you read voltage.


See Speedy Jim's page for better instructions
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1970 VW (owned since 1972) and 1971 VW Convertible (owned since 1976), second owner of each. The '71 now has the 1835 engine, swapped from the '70. Second owner of each. 1988 Mazda B2200 truck, 1998 Frontier, 2014 Yukon, 2004 Frontier King Cab. All manual transmission except for the Yukon. http://www.thesamba.com/vw/forum/album_page.php?pic_id=335294 http://www.thesamba.com/vw/forum/album_page.php?pic_id=335297

[Q-Dog]

I have been fooling around with these cars for a long time. Voltage regulators fail regularly, generators typically need new brushes every few years. If the generator spins when you polarize it, I would suspect the voltage regulator.

There are lots of posts detailing how to properly test the generator with a meter, and you should go through those tests before throwing parts at it. Do a Samba search for "generator test" and you should find a few.
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Brian

'69 Dune Buggy
'69 Beetle Convertible
'70 Beetle

[elutfall]

I read a bunch, including Speedy before posting. It is plain weird, which is why I posted. Brushes are new, and pressing on them while the generator us running makes no difference in the voltage.
Is there a different setting I should be using on the voltmeter than the setting I use when testing the battery? The battery reads fine, but the gen reads under 1 volt.
I even did a test I saw on YouTube where I used a drill to spin the generator while testing. Same reading.
Since it reads non-zero and it spins when polarizing, I figure it's got just enough life to spin when power is applied, but not enough to put out any voltage.
Right now I'm struggling to get that darned 36mm off of the back. It won't budge. If I can manage to get it out, I'll get it tested at a shop. That 36mm bolt doesn't have reversed threads, does it? It's still counterclockwise to loosen it, yes?
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74 Standard Body on a 70 Chassis
Front Ghia disc brakes on lowered spindles
2110cc engine, Dual Dell 40's
Rancho Trans w/ Type 2 shafts

[ashman40]

[mtdorajohn]

I had the same problem months back and found the DF wire had broken away from the DF stud inside the generator.

I soldered the wire back to the stud and it is all good now...

[elutfall]

ashman40 - yes to all the testing wiring, and thanks for thread confirmation

mtdorajohn - that intrigues me, as when I first started this I noticed the DF post was a little loose. I tightened it up, but never checked inside. I'll look into that.

Still haven't managed to break that nut. I may have to drop the engine just to get the leverage I need.
_________________
74 Standard Body on a 70 Chassis
Front Ghia disc brakes on lowered spindles
2110cc engine, Dual Dell 40's
Rancho Trans w/ Type 2 shafts

[Cusser]