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Author Topic: Alternator wires  (Read 286 times)

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Offline stecer

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Alternator wires
« on: October 28, 2020, 08:37:42 pm »
I have read quite a lot about alternator wiring on the C11g but mine has some odd colours and I wonder if anyone else has the same. Any advice about wiring it up would be gratefully received.

Thanks,
Steve
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Offline John M

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Re: Alternator wires
« Reply #1 on: October 28, 2020, 09:51:30 pm »
There are a few threads re alternator wiring - put " alternator " in the search box.

One which may help you is https://bsac10c11c12.co.uk/smf/technical/c12-rectifier-alternator-connections/msg24327/#msg24327
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Online timsdad

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Re: Alternator wires
« Reply #2 on: October 29, 2020, 07:29:44 am »
Difficult to see the tracer colours on my screen, Steve, but they don't look far off standard Lucas/BSA colours to me. If my memory serves me right, they should be green/white, green/yellow and green/black.

If you're going to twelve volts, the green/yellow and green/black are joined together. You can't hurt these old electrics unless you've got a fancy electronic regulator/rectifier fitted, which are expensively easy to turn into blue smoke. The alternators, solid state rectifiers and Zenor diodes on a 12 volt conversion are almost indestructible so you an 'suck it and see'. The original six volt system, where the wiring goes up and down via the ignition/light switch, is also very robust so you can swap wires about and see how it goes to get the best charging rate.

Ray
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Just a motorcyclist.

Online chaterlea25

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Re: Alternator wires
« Reply #3 on: October 29, 2020, 09:30:58 pm »
Hi stecer,
It looks like you have a bit of work to do yet before being able to test the alternator and work out the non standard colours?
When you get the bike running (off the battery) in this topic I described how to test the output with a simple headlamp bulb, https://bsac10c11c12.co.uk/smf/technical/c11g-charging-problem/30/

Another way is to use a 6 volt battery to magnetise the alternator coils, (remove the stator first) and only connect the battery for a few seconds at a time, make a sketch of the alternator coils copied from the wiring diagrams
Testing the 3 wires in alternative pairs will magnetise either 2 , 4 or 6 coils, one wire will be the common that magnetises either 2 or 4 coils, the wire that magnetses 2 coils is the low or daytime output the one that magnetises 4 is the high,
Mark the  colours onto your sketch and then label them to suit the wiring loom

Easier done than written
John
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Offline stecer

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Re: Alternator wires
« Reply #4 on: October 30, 2020, 10:07:01 pm »
Thank you very much - such detailed responses are very much appreciated.
I have not gone for 12v as I have a new 6v coil and standard rectifier.
The vapour blasted barrel and head will be painted this weekend and assembled which will be a major milestone. Thank you for the testing routine for the alternator coils. I look forward to trying it out.

Steve
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