single phase and 3 phase alternators

Holeshot · Dec 15, 2009

I've got a '72 engine in a '70 fastback chassis and I'd like to install a Podtronics regulator/rectifier...Does that engine have a single or a 3 phase alternator and what is the difference? I've got 2 wires coming off the alternator...
Thanks.

Jeandr · Dec 15, 2009

2 wires = two phases
3 wires = three phases ( unless it's a very old stator in which case it is a two phase )

Jean

Holeshot · Dec 15, 2009

On the Podtronics diagrams for hooking up their products, it's either a single phase or a 3 phase...it doesn't mention 2 phase.

kommando · Dec 16, 2009

Jean meant to say single phase I am sure.

Ron L · Dec 16, 2009

2 - wires from the stator = RM-19 120 Watt single phase.

L.A.B. · Dec 16, 2009

Ron L said:
2 - wires from the stator = RM-19 120 Watt single phase.

I would expect a (pre-MkIII) Commando to be fitted with a two-wire RM21 47205 stator.
http://www.oldbritts.com/11_068100.html

Ron L · Dec 16, 2009

You are, of course, correct, Les.

I believe the RM-19 used the open stator with the two coils connected and the third separate (3-wires) used on the Atlas and others in the '60's, wasn't it?
(Or perhaps the 5-wire ET ignition stator used by the BSA Hornet and TT Triumph?)

Either way, they were not used on Commandos. My mistake.

L.A.B. · Dec 16, 2009

Ron L said:
I believe the RM-19 used the open stator with the two coils connected and the third separate (3-wires) used on the Atlas and others in the '60's, wasn't it?
(Or perhaps the 5-wire ET ignition stator used by the BSA Hornet and TT Triumph?)

Either way, they were not used on Commandos. My mistake.

I thought you really meant RM21, Ron!

Yes, the RM19 is a three-wire single-phase type, and I believe it was also made as a four-wire type for ET ignitions (according to the Lucas service notes).

Jeandr · Dec 16, 2009

kommando said:
Jean meant to say single phase I am sure.

I think Cristmass is getting to me or it's the fact I finished my bike and I have to do other things around the house or it's my brain hibernating while my body must stay awake, at any rate, you are absolutely right

Jean

Coco · Dec 16, 2009

Been thinking about this for another project I'm working on.

Would I need a single or three phase alternator for a bike with a magneto? It will just have a headlight and tail/brake lights. No battery and just a capacitor.

Jeandr · Dec 16, 2009

Doesn't matter, 1 or 3 phase would work. The lights would probably be dim at idle though.

Jean

Coco · Dec 16, 2009

Jeandr said:
Doesn't matter, 1 or 3 phase would work. The lights would probably be dim at idle though.

Jean

Thanks Jean. I was going to use a 3 but have been told a single will be fine. Maybe I'll stick with a 3 phase.

single phase and 3 phase alternators

Holeshot

Jeandr

Holeshot

kommando

Ron L

L.A.B.

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Ron L

L.A.B.

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Jeandr

Coco

Jeandr

Coco

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