Misc: Ignition/Mag-Dynos Miller Mag-Dyno Parts Needed

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timetraveller

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As I understand it the permanent magnet alternators try to output their maximim all the time and that has to be regulated. Alternators like those that I use only produce as much as is needed at the time as the field winding voltage is controlled by the regulator. The thirty or forty amp output would only ever be there for seconds unless there was a short or one is trying to run an inverter and cooker off the bike.:eek:
 
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delboy

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Here is the only picture I could find of the Miller Dynomag.
delboy
 

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Bill Thomas

Bill Thomas

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After reading "Norton Powers Bit",
I thought I remembered, A Clutch on a Mag/Dyno,
Did Ron's "A" Twin use a Lucas unit ?.
I googled Mag/Dyno.
 

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A

A Nut

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You will have trouble using the Lucas geardrive components because the Lucas magnetos all have a 45mm drive height but the Miller (and BTH) use a 35mm shaft height. The late Bob Stafford said that you could mill 10mm off the bottom of the Lucas Magdyno and then mill the magneto platform (we are talking Series A here) to allow the tufnol gear to drop through. I have seen one pair of crankcases that had the platform removed probably after the mod went wrong. Nigel (the club bike) has had a toothed belt drive on it for years and gets quite a bit of use. The belt has broken probably twice but without any damage. My A Comet, Mitch Talcove's and a number of others are still using toothed belt drives. I originally used aluminium pulleys but they do wear. Anodizing them or better still using steel pulleys would be best. The duplex chains are an obsolete size and if they break they will usually wreck the magneto armature as the chain will wrap around the sprocket. With regard to using polyvee belts I don't think that the magneto bearings would stay in situ because of the tension needed to prevent slippage. I don't know of anyone making or selling sprockets to fit the Miller dynamo. Brian.
 
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timetraveller

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I have no axe to grind in this discussion but in my experience the polyvee belts do not require a lot of tension but it might depend upon what width is available as to how many chords, the width of the belt, you can get in there. The multiple vees give more contact area and seem to give some extra grip so one might be usable. Washing machines and some Flymo grass cutters I have seen use one multi vee formed driving pully and one large plain driven pulley, i.e. no grooves, and get away with it. I tried it first with the Walkernators, in order not to have to line up pullies, but it slipped.
 
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oexing

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Obviously so far I knew nothing about the Miller Magdyno - and not much about same type Lucas. The Lucas got some friction protective clutch on the tufnol drive gear but the Miller not so. Seems Miller had a v-belt drive instead , changed to chain and sprockets. Not a great step I´d think. No wonder there were troubles in the Miller drive then, no friction protection in there. As power output is only less than 50 W the basically very low loads and troubles on drives have their roots in the mass of the armature whenever there are fast changes in rotational speeds, multiplied by the ratio of sprockets or gears. So some kind of friction damping is essential for protecting the drive. Easiest way is having some belt drive , vee-belt like earlier Millers, or poly-vee type, maybe flat belt types too. So no, chain drive is not a great idea as obviously somebody had to do a mod on that Miller with stripped tooth belt.
Permanent magnet alternators cannot be regulated but they don´t waste power at overvoltage - unless you got a common motorbike "regulator" . My first test regulator turned all excessive power/voltage into heating up the alternator by shorting one phase, plus heating up the regulator in no time. So I got voltage converters from Ali for getting 13.8V from the servo motors via 3ph rectifier. No feedback into the "alternator" then as the rectifier sits in between . These converters are used in solar power systems I believe and you do not want to go all overvoltage up in heat there ! And no, without real load from bulbs hooked to the converter setup there is no force produced by the servo motor/alternator as I can easily hold the motor with one hand spinning at 2000rpm plus. Reaction force only comes when bulbs are connected, but a strong grip of hand is all you need - with 200 W or more generated at 13.8 V .
For my Bosch "magdyno" I got a small servo with more than 50 W I hope, very low rotor mass then. So that is what I´d get in case I had a Miller magdyno on my bike. Certainly with some belt drive to go with it - but no toothed type.
As for looks, with some more efforts you could hide the servo under some nice covers on the Vincent engine. Way nicer than car alternators plus belt drives and more than 200W available from these servos, depending on body length in 4 types.

Vic


voltage converter:







magneto Miller Dynamag.jpg




Lucas magdyno.jpeg



P1090664.JPG


P1090667.JPG
 
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Stanley Chappell

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I have fitted aluminium pulleys to my miller magdyno but whould have preferred steel
but I have not been able to find a supplier can anyone help
many thanks stanley chappell
 
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