LED replacement numberplate light?

No they were all single phase

dont know what is wrong with you younger generation im still happily using magnetos and points ignition but im not a fit and forget person.

They were wound as a 3-phase star-connected alternator, with each pair of the phases coils having a different gauge and turns ratio. Only one pair of coils were connected at a time - a very inefficient design.

From that perspective, they became to be known as single phase alternators, as only one phase was connected at any one time. From the perspective of an electrical engineer, they were a 3 phase device, so I guess we are both right!

As an aside, in the early 1960's I started an electrical apprenticeship at a company that amongst other things did electrical rewinds, and I successfully rewound a couple of the six-coil ones.

Chris

Whilst I enjoyed that benefit (of contactless ignition), I can't say I really had much of an issue with the points (but then my annual mileage was often spread over several vehicles, one of which had two sets of points ).

And that's the sort of thing I was talking about elsewhere ... the times when many people (mostly men?) actually rolled their sleeves up and did real stuff themselves (not just buying a unit and fitting it even but making the unit / part themselves).

Of course, because you made it, it isn't broken and you never know when you might need / use it next. ;-)

Cheers, T i m

dont see how you could call them 3-phase when they are connected to a single phase bridge rectifier they may have 3 pairs and 3 output wires but one wire is common and all six coil are identical in gauge and turns ratio and all coils are connected when used in 12volt Lucas 47205 Stator RM21 conversion and when headlamp is on in 6volt use too many inaccuracies in you description The Real later 3-phase alternators are star-connected and have 9 coils

hmmm

Smaller Hondas also used single phase 6 coil permanent magnet (PM) alternators. One pair of coils were used when the lights were off. The other 2 pairs were switched in by the headlamp switch. Mid 70's 12V PM Hondas used a SCR to short the alt output coils and regulate volatage. Smaller 6V Hondas switched a resistor into circuit to dissipate headlamp load when on side lamps. the load wasn't regulated but balanced.

No one in their right mind would switch off the output from any of the coils when higher output for lighting was needed. They just connect more coils in parallel.

Some of the Brit bike PM alternators were timed and there was an "emergency" position on the switch that connected the alt direct to the ignition coil and nothing else.

Some Triumphs for the US market used a similar system permanently, because riders there often removed all the lights for desert riding.

I don't know how well it worked; I always found trying to start on 'Emergency' was errr - a bit of a non-starter.

Chris