Hitchcocks Forum

Hi all. I have a question about alternator output.

There are 6 coils on the alternator stator from my 1996 535cc Bullet (I now understand this was an indian home model rather than a UK export but that may not matter in this case). Three wires come from the alternator, white, green and purple – presumably this means it is a three phase output, and I assume the three wires each represent a pair of alternator coils (probably opposed pairs). The white wire goes to one terminal of the rectifier and the green and purple are connected together and go to a second of the four terminals.

But why are those two connected? Surely the summed output of the connected pair will be less than twice the single phase output from each wire, which must mean that the output is not three-phase, just a sort-of ~2-and-a half phase.

For those who seek to add power-drains, such as heated handlebar grips, spotlights or a power take-off for camera charging etc, why not wire it up so that the full three phase is sent to a three-phase rectifier?

Any comments?
Cheers, ChrisD

I think you will find that the white is the comon one, and the other two used to be seperate sets of coils for 6 volt setup.The old lighting switch used to bring in the second pair of coils when the headlight was turned on, giving full output. When things went 12 volt, the two wires were connected together for full output all the time, the voltage regulated by the zener diode on brit bikes, but regulated by a ......regulator on our bullets. The coils became connected in later stators internally, and only 2 wires came out.

Oh, and I forgot, the alternator is still single phase, I believe the 3 phase ones have 4 wires.

Lucas 3 phase alternators (and the pattern versions) have three wires, so do the Suzuki type 3 phase alternators used on the Electra-X models. 4 wire Lucas-oid alternators (as well as our hosts' 4 wire Lucas replacement) on an Indian Bullet mean single phase output for the rectifier/regulator from the purple wires and single phase AC feed to the headlamp from the yellow and amber wires. Other variations appeared on some Indian home market 350s.



A.

Hi Adrian, my mistake, I should know that, having a Sixty5 with ac headlight! But I believe the rest of my explanation is correct. After messing around with 12 volt conversion on my Ariel arrow years ago, and reading the "How to's" in Motorcycle Mechanics. If memory serves, I think the wire colours used to be light and dark green, but changed to purple and something later, if I was home, (in Spain at mo), I have various Lucas sevice books to check. Ray.

With white green and purple wires it is almost certainly a Lucas type 6v alternator wired for 12v, if three phase it would have three yellow wires for the output sometimes with a tracer. The different colours are needed to identify the different outputs to enable correct switching when used on 6v and also used to identify which 2 wires to common for 12v.