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Alternator Wiring Help Needed! #241890
03/09/09 2:07 am
03/09/09 2:07 am
Joined: Aug 2007
Posts: 20
Alabama
J
Jim Knight Offline OP
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Jim Knight  Offline OP
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Joined: Aug 2007
Posts: 20
Alabama
Iím hoping for some help from you electrical gurus. Subject bike is a 1967 T120R (purchased on E-Bay) with a 12-volt, positive earth electrical system. Recently I had to remove the engine and Iím now in the final steps of reassembly, but Iíve run into a puzzle with the alternator wiring. Prior to removing the engine, I made notes on the wiring connections. It was wired this way: from the alternator, the green/yellow and green/white wires were connected together, hooked to a green/yellow wire going into the harness. The green/black lead from the alternator was connected to a green/white wire going into the harness. Up at the rectifier (the original Lucas version), looking down from the grounded pole, the green/white wire was connected to the right pin while the green/yellow wire was connected to the left pin. The problem? This is backwards from what the wiring diagram in my workshop manual shows, and itís different from a couple of other references Iíve seen. Does the former wiring make sense? Should I hook it back up the way it was, or re-wire it ďcorrectlyĒ acconding to the wiring diagram? Whatís the danger in getting this wrong?

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Re: Alternator Wiring Help Needed! [Re: Jim Knight] #241911
03/09/09 7:40 am
03/09/09 7:40 am
Joined: Aug 2007
Posts: 4,542
Kent UK
Blapper Offline
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Blapper  Offline
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Kent UK
The output from your alternator is AC and not referenced to the DC ground of the motorcycle, and as the alternator output is AC it doesn't matter which way round those wires are connected. For example on my three phase all wires are the same colour.

HTH

Blapper redwine

Re: Alternator Wiring Help Needed! [Re: Blapper] #241919
03/09/09 9:12 am
03/09/09 9:12 am
Joined: Apr 2008
Posts: 266
Bordon, England
D
Derry Hincks Offline
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Derry Hincks  Offline
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Joined: Apr 2008
Posts: 266
Bordon, England
Jim my manual shows the following: alternator leads green/black and green/yellow are connected together, they then connect to green yellow on the harness. Alternator lead green/white connects to green/white on the harness.

With your current wiring two of the alternators three phases would be shorted out.

Blapper is referring to later alternators connect internally in the star format, hence the leads being the same colour. Your alternator is connected internally in parallel.


Derry.

1969 T100S under reconstruction
GSX-R750K2 (having been rebuilt from a crashed wreck)
Re: Alternator Wiring Help Needed! [Re: Derry Hincks] #241920
03/09/09 9:45 am
03/09/09 9:45 am
Joined: Aug 2007
Posts: 4,542
Kent UK
Blapper Offline
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Blapper  Offline
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Kent UK
Hi Derry,

My point was that the colours are the same because it doesn't matter where those AC leads are connected - i.e. the two joined and single wires in Jims case.

Blapper redwine

Re: Alternator Wiring Help Needed! [Re: Blapper] #241930
03/09/09 12:39 pm
03/09/09 12:39 pm
Joined: Apr 2008
Posts: 266
Bordon, England
D
Derry Hincks Offline
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Derry Hincks  Offline
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Joined: Apr 2008
Posts: 266
Bordon, England
In your case, true Blapper. But I imagine this is what Jim has...
http://s692.photobucket.com/albums/vv286/Derryuk/?action=view&current=1.jpg

Here you can see connecting alternator GY to GW is a no-no.


Derry.

1969 T100S under reconstruction
GSX-R750K2 (having been rebuilt from a crashed wreck)
Re: Alternator Wiring Help Needed! [Re: Jim Knight] #241933
03/09/09 1:13 pm
03/09/09 1:13 pm
Joined: Nov 2005
Posts: 7,258
Back on the mainland!
JubeePrince Online content

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Originally Posted By: Jim Knight
Up at the rectifier (the original Lucas version), looking down from the grounded pole, the green/white wire was connected to the right pin while the green/yellow wire was connected to the left pin. The problem? This is backwards from what the wiring diagram in my workshop manual shows,


Jim,

The short answer is no, it's not a problem, because it's Alternating Current....as long as you have a G/W and G/Y wire going the the rectifier, it does not matter if they're on the 'left' or 'right'.....

HTH,

Steve


'77 T140J
"Vintage Bike". What's in your garage?

"The paying customer is always right."

Fitting round pegs into square holes since 1961...
Re: Alternator Wiring Help Needed! [Re: Jim Knight] #242020
03/09/09 7:34 pm
03/09/09 7:34 pm
Joined: Jun 2002
Posts: 9,463
Scotland
S
Stuart Online content
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Stuart  Online Content
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Joined: Jun 2002
Posts: 9,463
Scotland
Hi Jim,

Originally Posted By: Jim Knight
the green/yellow and green/white wires were connected together, hooked to a green/yellow wire going into the harness. The green/black lead from the alternator was connected to a green/white wire going into the harness.

If it was wired this way, it wasn't wired correctly in the first place!

Today, the first thing you have to be careful of is what sort of 3-wire stator you have. Before the RM21 and RM23 2-wire stators (introduced in about 1969), from about 1960 on, Triumph fitted either the RM19 or RM20 (usually the former) 3-wire single-phase stators. The thing about these is that they could generate either 6V or, if connected in a similar (but definitely not the same!) way as yours, 12V.

Otoh, from '78, Lucas produced RM24 3-phase stators, which were both fitted as original equipment to Meriden twins from '79 and were/are available for after-market fitting in place of an RM19, RM20, RM21 or RM23. While, unfortunately, Lucas chose to use exactly cry the same wire colour combinations on the 3-phase stators as they had on the 3-wire single-phase ones, you cannot connect any of the leads on a 3-phase to any other; they can be connected only to a 3-phase rectifier or 3-phase version of one of the electronic reg./rects. A quick way to check whether you have a single- or 3-phase stator is look at the inside circumference - if it has six slight protrusions (the poles), it's a single-phase; if it has nine, it's a 3-phase.

Assuming the dpo that made the previous connections has at least tried to connect a single-phase stator, his (or her) error will be more understandable, and you'll be less likely to repeat it, if you take a closer look at the insulation colours of the three cables. While you've correctly identified Green/Yellow and Green/Black, because the insulation is mostly Green with just a trace(r) of the other colour, what you've called 'Green/White', in fact, should be mostly White with just a trace of Green; as such, it's better known as White/Green. Here, the distinction's important because, when connecting a 3-wire single-phase stator to generate 12V, it's the two mainly Green cables that should be connected together and the mainly White cable that should be left separate.

Originally Posted By: Jim Knight
Up at the rectifier

As Steve has said, because the alternator generates alternating current, as long as each cable from the stator is connected to one of the outer tabs, it matters not which cable is on which tab.

Hth.

Regards,

Re: Alternator Wiring Help Needed! [Re: Stuart] #242031
03/09/09 8:05 pm
03/09/09 8:05 pm
Joined: Aug 2007
Posts: 4,542
Kent UK
Blapper Offline
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Blapper  Offline
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Joined: Aug 2007
Posts: 4,542
Kent UK
Derry,

Isn't mis-communication a wonderful thing! I didn't for a minute consider that some dpo-stick had wired it wrong in terms of which wires were connected together and which left alone, I simply meant that the wires can be connected to the rectifier in any order. Hence my reference to my three phase having three yellow wires which can go to any input of my three phase powerbox.

Which is what others said afterwards..

Blapper redwine

Re: Alternator Wiring Help Needed! [Re: Stuart] #242035
03/09/09 8:09 pm
03/09/09 8:09 pm
Joined: Apr 2006
Posts: 1,708
Virginia, USA
SBoyd Offline
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SBoyd  Offline
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Joined: Apr 2006
Posts: 1,708
Virginia, USA
Jim
Stuart is correct in everything he said, but it may be confusing.

The alternator was definitely wired incorrectly which may or may not have damaged it, and it would definitely not have been putting out its rated wattage.

Of the three wires coming out of the alternator, the G/B and G/Y should be tied together.
That combo goes to the G/Y harness wire leading to the rectifier.
The W/G goes to the W/G harness wire leading to the rectifier.

As Steve said, at the rectifier, it doesn't matter which wire is on which side.

As Stuart said, it is possible that a three-phase stator was fitted. Very unlikely, but if you want to check it, count the poles.

>>sb


Stop the insanity.
Re: Alternator Wiring Help Needed! [Re: SBoyd] #242044
03/09/09 8:49 pm
03/09/09 8:49 pm
Joined: Apr 2008
Posts: 266
Bordon, England
D
Derry Hincks Offline
BritBike Forum member
Derry Hincks  Offline
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D
Joined: Apr 2008
Posts: 266
Bordon, England
Forgive me Blapper, it's me age. I just feel for Jim though, even my head is realing with the echos in here <s>.


Derry.

1969 T100S under reconstruction
GSX-R750K2 (having been rebuilt from a crashed wreck)
Re: Alternator Wiring Help Needed! [Re: Derry Hincks] #242092
03/10/09 12:24 am
03/10/09 12:24 am
Joined: Aug 2007
Posts: 20
Alabama
J
Jim Knight Offline OP
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Jim Knight  Offline OP
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Joined: Aug 2007
Posts: 20
Alabama
Thanks to you all. I think I get it!
Jim

Re: Alternator Wiring Help Needed! [Re: Jim Knight] #242094
03/10/09 12:41 am
03/10/09 12:41 am
Joined: Apr 2006
Posts: 1,708
Virginia, USA
SBoyd Offline
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SBoyd  Offline
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Joined: Apr 2006
Posts: 1,708
Virginia, USA
Derry
Sorry, FWER did not see your posts, which entirely and correctly answered the question.

So we had three correct posters and two dubious ones smile smile

Jim, you're all set. If your stator does not appear melted, it may have survived the short curcuit.

see you
>>sb


Stop the insanity.
Re: Alternator Wiring Help Needed! [Re: SBoyd] #242106
03/10/09 1:56 am
03/10/09 1:56 am
Joined: Nov 2005
Posts: 7,258
Back on the mainland!
JubeePrince Online content

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Posts: 7,258
Back on the mainland!
Originally Posted By: SBoyd

and two dubious ones smile smile


Hey! I resemble that remark! grin

Good to hear Jim! Post some pics when she's ready to go!

Cheers,

Steve Prince


'77 T140J
"Vintage Bike". What's in your garage?

"The paying customer is always right."

Fitting round pegs into square holes since 1961...
Re: Alternator Wiring Help Needed! [Re: JubeePrince] #242142
03/10/09 11:33 am
03/10/09 11:33 am
Joined: Apr 2008
Posts: 266
Bordon, England
D
Derry Hincks Offline
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Derry Hincks  Offline
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D
Joined: Apr 2008
Posts: 266
Bordon, England
<Sorry, FWER did not see your posts>
No worries I was really saying it's good to see some posts about alternators for once.

All most people want is how to make a few simple checks to say is this alternator and what I have done go or nogo. When I were a lad if someone said "6 1/2 volts into 1 ohm" my thoughts would have been 'so he thinks it's broken then'.


Derry.

1969 T100S under reconstruction
GSX-R750K2 (having been rebuilt from a crashed wreck)

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