Single or three phase alternator

Reading through the AV website I see for the 72 Roadster a 3 phase rectifier/regulator is available???, as I has RM21 single phase (2 wire) this isn't needed
So my questions
1. On the 72 model was a 3 phase set up available.... are these stators still available??
2 Will the later RM23 stator (2 wire single phase) fit directly without an modification?

Many thanks & a very happy Christmas

they never put the 3 phase on a norton but they are IMHO a better way to upgrade the charging system so yes they are still available. the rm 21 is a a direct fit but i would trust the stoce rectifier or zener with a higher output stator.

olympus said:

Reading through the AV website I see for the 72 Roadster a 3 phase rectifier/regulator is available???, as I has RM21 single phase (2 wire) this isn't needed
So my questions
1. On the 72 model was a 3 phase set up available.... are these stators still available??
2 Will the later RM23 stator (2 wire single phase) fit directly without an modification?

Many thanks & a very happy Christmas

Click to expand...

I had the 3 phase Lucas on my bike for years with the original rectifier and the added Zener that comes with the 3 phase alternator kit. It worked perfectly. Currently I have a Podtronics with the Alton E-start/alternator which "downgraded" my alternator back to stock (150W spec) but it works fine and will charge the batt at 1000 RPM with the headlight off and at around 1400 RPM with the headlight on (low beam).

olympus said:

Reading through the AV website I see for the 72 Roadster a 3 phase rectifier/regulator is available???, as I has RM21 single phase (2 wire) this isn't needed
So my questions
1. On the 72 model was a 3 phase set up available.... are these stators still available??
2 Will the later RM23 stator (2 wire single phase) fit directly without an modification?

Many thanks & a very happy Christmas

Click to expand...

The three phase puts out a lot of power at low RPM. They are a lot better than the single phase ones. You can still buy all the parts, and not just Lucas ones either. With an H4 headlight 55 watts I think my charging balances at about 2200 RPM. I don't run the engine slower than that anyway. I don't know how Mike got his to balance at 1400 RPM. Maybe he is using a 23 watt bulb. What I use to rectify and regulate the current are twin Lucas Rectifiers, the old plate type. I don't need to use all the connections though, I just use any three of the input terminals. I have a matched set of Zeners, one on each Z plate. If you leave the headlights on all the time probably one Zener would be enough. I have put about 25,000 miles on this bike since I built it about 7 years ago and it works very well. The reason I did it this way was to use up parts I had around so I didn't have to spend money. Also I think most of the old Lucas stuff was high quality and it lasts just about forever! I even have Lucas coils and a Lucas Rita ignition. Really it would have been better to build it with negative ground but I had to stick with positive ground because of the pieces I had. Negative ground would have made it much easier when I was running an Oxygen sensor to check my mixture.

It is a very good idea to instal a new rotor. The old ones blow up sometimes.

Nigel

Just to clarify - when I say the batt will charge with the headlight on at 1400RPM, I'm talking around 12.7-.8 volts, just BARELY a positive charge. Maybe the Alton 150W alternator is a bit more efficient than the OEM 150W Lucas. I never had the original charging system in this Commando. When I bought it in '06 it had the three phase 180W alternator/twin Zeners. I seem to recall back in the day with my '71 Commando that the discharge light was on with the headlight on at any RPM below around 1800-2k but that's from memory.

I'm using a sealed beam headlamp (From India by way of Old Britts); I don't recall the wattage.

Why would you downgrade a 3 phase system back to the lesser OEM (or equiv) system?

BrianG said:

Why would you downgrade a 3 phase system back to the lesser OEM (or equiv) system?

Click to expand...

Because the Alton electric start kit has its own alternator and that's what it's rated at , cheers

Yep. FWIW, I can't tell any difference between the 150W Alton and the 180W Lucas as as far as practical performance. Of course, if I had additional accessories - heated gloves/vest, etc, I'm sure the 180 would be better but since I don't, it works fine. But, as noted by baz, there was no choice anyway since the Alton alternator is required for the Alton E start.

Get a LED color change volt meter to replace the stock amber "engine now running" alert light then fit lighter battery and just shift to spend more time in green rpm than mixed amber or red color, so any alternator can work fine. If in conditions requiring many minutes on end of rpm below charging with factory alternators, such as rainy rush hour congestion or rural Mt. gravel paths, an after market 3 phase 210 watt'r can be the difference between just nice amble home on hi beam or stalling out each brake light activation w/o volts enough to restart by kicker.

Nobody is talking about a load analysis. The ancient and inefficient charging system used in almost all motorcycle, even today's models, is not designed with the more-is-better perspective.
Unlike automotive alternators which shut off when the battery is fully charged, motorcycle regulators short circuit the extra current to ground. That's how the zenner diode works as the Norton voltage regulator.
This "short" creates heat, and zenner diodes and other solid state voltage regulators have current limits, which when exceeded kills the regulator.
So a lot of extra capacity in a motorcycle charging system is not only a waste, it could be a detriment to the regulator.
I'm not seeing much conversation here about load calculation and building a balanced charging system.

If sticking to what fits on end of crank, only need discussing, how much to spend, setting clearances and rotor robustness or tracking bad conductors under intact insulation etc. Lucas did good job for the price of matching output to consumption of factory components so Zenors or nonNorton rect/regs often don't get much heat load to dump.

Ammeters should have both terminals connected to the two neg voltage sources, one side to - battery the other to alternator out put to see which is working harder to supply current drain. Not very bright to have whole power flow going through one meter bottle neck, only the differences.

So be first on your block to create an all electromagnet 3 phase coil alternator with 3rd wire volt sensing to allow charging at idle with lights on while holding brake beeping bee-under-bonnet horn at cold rainy rush hour traffic wishing for heated clothing. I designed one based on DIY windmills but decided against it.

https://www.google.com/search?clien...AhKbYAhUk8IMKHTI-A5gQBQgmKAA&biw=1088&bih=476

When I bought my Commando it was my only transport so it got used to take me to and from work every day. This was into the centre of Birmingham so plenty of slow moving traffic and in the winter dark both ways. I used to have to charge my battery every few days as the charging system was inadequate. While the bike was still under warranty I complained about this to the dealer who then referred me to Norton themselves. As I lived in the Birmingham area, Norton got me to take the bike to Lucas's own service centre. They checked everything over and said everything was working as it should. The service manager told me that Lucas had told Norton that fitting indicators to the Commando would mean the 110 watt alternator couldn't cope but at that time Lucas had nothing else to offer them. The 3 phase alternator appeared after Commando production ceased, but did solve the problem.

Ian

If your ethics allows jumping Norton fences, like Mz Peel, can have 10,000 rpm rated 9 lb 3 phase 3 wire 650 watt compact modern wonder charger spin backward to nullify some the other flywheel gryo's. A bonus is can just un plug, pull one bolt to remove and run off tiny 2.4 ah lead or lighter Li battery for short special events.

Going slow is about only time charging an issue so dashed plan of bicycle tire friction drive charger but would still work for a swval mount siren saving horn draw down.

Something else few consider on Commando rpm limits is crank flex can cause rotor to collide with stator which puts a stronger distortion wave back through crank, maybe enough to bind rods on journal angles tipping short crank ends leverage to stress cases to pop in half.

Go with the 3 phase and Podtronics, leave a nice bright halogen headlight on all the time and don't worry about it. Also install a voltage monitoring LED to assure yourself it's charging:

http://www.sparkbright.co.uk/sparkright-eclipse-battery-voltage-monitor.php

Not to forget that moving to LED lamps will greatly reduce the amount of power needed so going to three phase may be excessive. Well for non electric start anyway.

Make better use of what you have, either single phase or 3 phase will work perfectly when you rectify all the stator output and not what is left over from being robbed elsewhere.