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talljordan
Samba Member
Joined: January 10, 2012
Posts: 1062
Location: San Francisco, CA
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 Posted: Sat May 17, 2025 9:50 pm Post subject: Generator issues! |
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My car sat for the better part of a decade. The generator definitely worked when it was parked.
At the moment, when the car is running, I get about 2V off of D+ on the generator.
I tried to polarize it by connecting DF to gnd, and then applying 12V to D+, however the generator did not spin. Do I need to hand spin it first? Then apply the voltage while it is spinning?
Visually, the brushes and everything look okay.
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1972 Super Beetle, Parked until adequate restoration funding is acquired in restoration!
Wanted: Male computer diagnostic plug end |
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talljordan
Samba Member
Joined: January 10, 2012
Posts: 1062
Location: San Francisco, CA
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| Posted: Sat May 17, 2025 9:57 pm Post subject: Re: Generator issues! |
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Perhaps also worth mentioning, I ran the vehicle for quite a while with DF fully disconnected and floating. It somehow got pulled off the regulator and I didnt notice.
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1972 Super Beetle, Parked until adequate restoration funding is acquired in restoration!
Wanted: Male computer diagnostic plug end |
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talljordan
Samba Member
Joined: January 10, 2012
Posts: 1062
Location: San Francisco, CA
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| Posted: Sat May 17, 2025 10:59 pm Post subject: Re: Generator issues! |
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After poking my fingers around inside and testing with a multimeter, it seems that DF is totally disconnected and floating.
My understanding is the DF peg should be connected to one side of the field windings. How is this connection made? I may try and connect/rebuild myself.
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1972 Super Beetle, Parked until adequate restoration funding is acquired in restoration!
Wanted: Male computer diagnostic plug end |
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baldessariclan
Samba Member
Joined: October 14, 2016
Posts: 1962
Location: Wichita, KS
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| Posted: Sun May 18, 2025 4:55 am Post subject: Re: Generator issues! |
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| talljordan wrote: |
| I tried to polarize it by connecting DF to gnd, and then applying 12V to D+, however the generator did not spin. Do I need to hand spin it first? Then apply the voltage while it is spinning? |
Apply voltage first, and then give it a turn with your fingers — make sure you spin it in the right direction (way it normally turns while on the car). More details here: https://www.speedyjim.net/htm/gen.htm
You can also directly test if your generator is working or not via the process described in these shop manual excerpts and pictures. Make sure to keep this test pretty short so that you don’t overheat or burn out any wiring:
For reference purposes, here are a couple pics I took a few years ago when I was testing my generator’s voltage output.
Generator test connections — Regular “D+” and “DF” wires disconnected and isolated. “DF” terminal connected to generator body “D-” ground point via heavier gauge wire. Multimeter leads connected between “D+” terminal and “D-” ground point:
Generator voltage read w/ engine at high idle speed (maybe 950 rpm or so - ?):
I can’t find a picture of it, but when I advanced my engine speed a bit more (up to around ~2,000 rpm range), the voltage reading jumped to about 35+ V. Figured my generator was indeed operating satisfactorily at that point...
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1971 Standard Beetle — fairly stock / driver
baldessariclan -- often in error, never in doubt... |
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Cusser
Samba Member
Joined: October 02, 2006
Posts: 32847
Location: Hot Arizona
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talljordan
Samba Member
Joined: January 10, 2012
Posts: 1062
Location: San Francisco, CA
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| Posted: Sun May 18, 2025 5:46 pm Post subject: Re: Generator issues! |
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Got it sorted, what happened is that the DF peg broke off the field winding wire when I tightened its nuts down. The peg spun and snapped the end off the wire.
Thankfully I have some silver solder. So I pulled the front of the generator off (lost the woodruff key, hopefully not too important). And had to solder it through the hole opening.
A very finnicky and difficult job admittedly, but I got it done. I heated the peg with a propane torch after I removed the plastic insulation. Then I applied a bit of silver solder, then I touched the wire to the molten solder and prayed.
This took about 20 attempts, but the generator now works!
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1972 Super Beetle, Parked until adequate restoration funding is acquired in restoration!
Wanted: Male computer diagnostic plug end |
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scarabee
Samba Member
Joined: May 14, 2021
Posts: 131
Location: South Africa
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| Posted: Mon May 19, 2025 5:50 am Post subject: Re: Generator issues! |
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| Great for getting the generator to work, but I'd say that the Woodruff key is important. |
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Cusser
Samba Member
Joined: October 02, 2006
Posts: 32847
Location: Hot Arizona
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| Posted: Mon May 19, 2025 6:35 am Post subject: Re: Generator issues! |
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Tall - that looks a little sketchy to me, like someone used a machine screw inserted from inside, and maybe there is/was no hold-down securing nut to prevent that from turning. I can see a hold-down nut on the other connector.
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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 |
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sambuc
Samba Member
Joined: August 09, 2023
Posts: 28
Location: North Alabama
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| Posted: Mon May 19, 2025 6:56 am Post subject: Re: Generator issues! |
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| I consider the woodruff key to be extremely important. If the pulley spins on the shaft the engine can/will overheat because the fan won't be pushing air as it should. Replace the key! |
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Cusser
Samba Member
Joined: October 02, 2006
Posts: 32847
Location: Hot Arizona
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| Posted: Mon May 19, 2025 1:03 pm Post subject: Re: Generator issues! |
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| sambuc wrote: |
| I consider the woodruff key to be extremely important. If the pulley spins on the shaft the engine can/will overheat because the fan won't be pushing air as it should. Replace the key! |
ABSOLUTELY !!!
I don't know if Ace Hardware near you stocks metric woodruff keys, but you MUST obtain one. It's termed a 5mm x 5mm size.
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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 |
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ashman40
Samba Member
Joined: February 16, 2007
Posts: 16485
Location: North Florida, USA
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| Posted: Mon May 19, 2025 2:10 pm Post subject: Re: Generator issues! |
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| sambuc wrote: |
| I consider the woodruff key to be extremely important. If the pulley spins on the shaft the engine can/will overheat because the fan won't be pushing air as it should. Replace the key! |
OP, in case you were looking for a replacement:
https://wolfgangint.com/generators-alternators-sta...27051.html
https://www2.cip1.com/vhd-n12-7051-2/
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AshMan40
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'67 Beetle #1 {project car that never made it to the road  }
'75 Beetle 1200LS (RHD Japan model) {junked due to frame rot}
'67 Beetle #2 {2019 project car - Wish me luck!} |
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