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lboos Samba Member
Joined: November 20, 2015 Posts: 410 Location: Marietta GA.
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Posted: Thu Jul 29, 2021 8:55 am Post subject: What's this wire for ? |
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I was looking over the engine on my 71 SB and found this wire not connected on the Gen. aft of the hold down strap, I have not had prob. with the gen, no warning lights or weak batt. everything seems to be normal, should I just keep on driving like this ?
The last time the engine was worked on was last may when I had the engine rebuilt, since then I have been driving it with no prob. thanks for any ad
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NachoCar Samba Member
Joined: June 17, 2013 Posts: 323 Location: Ms
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Posted: Thu Jul 29, 2021 9:00 am Post subject: Re: What's this wire for ? |
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I'm no electrician....but I just bought a black alternator that had a ground wire.
That's my guess |
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raydog Samba Member
Joined: February 09, 2006 Posts: 1163 Location: Cape Cod
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Posted: Thu Jul 29, 2021 9:12 am Post subject: Re: What's this wire for ? |
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Yes, it's a ground wire. Just secure it with a screw at the tapping right next to where the wire is in your pic. _________________ Come on, It's not rocket science. KISS |
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Glenn Mr. 010
Joined: December 25, 2001 Posts: 76940 Location: Sneaking up behind you
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Posted: Thu Jul 29, 2021 9:26 am Post subject: Re: What's this wire for ? |
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Sure looks like it gets grounded to the threaded hole in the alternator. _________________ Glenn
74 Beetle Specs | 74 Beetle Restoration | 2180cc Engine
"You may not get what you pay for, but you always pay for what you get"
Member #1009
#BlueSquare |
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60ragtop Bonneville Belt Bitch
Joined: March 13, 2006 Posts: 7800 Location: Big Wonderful WYO 82401
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Posted: Thu Jul 29, 2021 9:32 am Post subject: Re: What's this wire for ? |
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_________________ Rick
Certified Mechanic by the State of Michigan in 1977
ASA certified in 1987
Certified Hunter Wheel Alignment Master Technician 1986
tasb wrote: |
I've restored a large number too, but I don't toot my horn quite as loud.
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sb001 wrote: |
maybe he just snapped cause his car sucked |
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ashman40 Samba Member
Joined: February 16, 2007 Posts: 15987 Location: North Florida, USA
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Posted: Thu Jul 29, 2021 11:54 am Post subject: Re: What's this wire for ? |
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Above replies are correct. That should be the D- ground wire running between the generator body and the VR body. By connecting the grounds between the two it ensures the generator output voltage, as read by the VR, is measured from the same ground potential. Will it work without the wire connected? Sure, but the voltage reading could be different, resulting in a small over or under charging condition. _________________ 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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lboos Samba Member
Joined: November 20, 2015 Posts: 410 Location: Marietta GA.
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Posted: Thu Jul 29, 2021 2:01 pm Post subject: Re: What's this wire for ? |
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Thanks for all the info. I looked all over for the right screw, took the one out of my 72 and matched it at the hardware store, I guess I'm all legal again .
Thank you all. |
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Rome Samba Member
Joined: June 02, 2004 Posts: 9654 Location: Pearl River, NY
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Posted: Thu Jul 29, 2021 7:32 pm Post subject: Re: What's this wire for ? |
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Quote: |
took the one out of my 72 and matched it at the hardware store |
I "think" the size was M5 x 0.75 mm and about 4 mm long, but good that you're all set.
Next time you're back at the engine and feeling productive, you can loosen the generator clamp (13 mm wrench) and rotate it clockwise 1/4 turn so that the clamp joint is pointing straight to the right; at "3:00" position. The clamp has preformed bends that conform to the underside of the generator support. Use a box-end wrench to hold the nut on the underside, and a socket with extension to reach down to the bolt. |
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lboos Samba Member
Joined: November 20, 2015 Posts: 410 Location: Marietta GA.
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Posted: Fri Jul 30, 2021 6:53 am Post subject: Re: What's this wire for ? |
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Rome,
Thanks for that helpful info. on the gen. clamp. I like to keep things the way they were meant to be. I readjusted the clamp.
You can learn something new here everyday. |
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MrGoodtunes Samba Member
Joined: May 14, 2012 Posts: 852 Location: South Florida
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Posted: Sat Jul 31, 2021 8:49 am Post subject: Re: What's this wire for ? |
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ashman40 wrote: |
... By connecting the grounds between the two it ensures the generator output voltage, as read by the VR, is measured from the same ground potential. Will it work without the wire connected? Sure, but the voltage reading could be different, resulting in a small over or under charging condition. |
Thank you @ashman40 for this explanation (as well as your many other helpful posts). It motivated me into hooking up such a wire from alternator case to voltage regulator mounting bolt:
But then, I re-read more carefully; and caught this part:
ashman40 wrote: |
... That should be the D- ground wire ... |
I'm pretty sure that D- is one of the 3 wires (D-, D+, DF) running from the plug on top of my ~1973 alternator to its external voltage regulator. So maybe it's a wasted effort, tho surely can't hurt. And it was a good excercise, taking things apart, cleaning out 29 years of accumulated funk since building this setup for my buggy which has gone ~92,000 miles without the newly added ground wire. |
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TK-CS Samba Member
Joined: April 15, 2019 Posts: 279 Location: D - Deutschland
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Posted: Sat Jul 31, 2021 3:51 pm Post subject: Re: What's this wire for ? |
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I think that's not neccessary on the externally regulated alternator. The brown wire is already there in the plug. _________________ AC:
'71 1600LE (Type 3 Notchback FI/AT) Sunroof
'75 1303 (Super Beetle) 1600DP, Sunroof
WC:
'77 Audi NSU Ro80
'88 GTI 16V
'91 Corrado G60
Daily:
'04 Passat Wagon 2.0TDI
'13 Passat Wagon 2.0TSI |
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MrGoodtunes Samba Member
Joined: May 14, 2012 Posts: 852 Location: South Florida
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Posted: Sun Aug 01, 2021 8:39 am Post subject: Re: What's this wire for ? |
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TK-CS wrote: |
I think that's not neccessary on the externally regulated alternator. The brown wire is already there in the plug. |
Thanks for confirming. Coinsidentially, it was the brown color match that first clue'd me into re-reading and noticing "D-" and "ground wire" were used interchangeably; when in fact, my choice of using a brown wire was because it was the only piece of wire in my stash with a good length and gauge for this job; its color was just a side bonus, brown being a color similar to Earth ground. |
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