Author Topic: dynamo part 2  (Read 1311 times)

Offline frankenstein

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dynamo part 2
« on: 24.09. 2008 18:44 »
fitted dvr2 solid state reg today....too early to give a full report......also i have got my dyno up and can gain access to the dynamo whilst leaving the timing side case on by undoing thd dyna clamp and sliding it towards the primary chain side of the engine...this gives just enough room to undo the clamp on the dynamo bakerlite outer case and metal cover....on looking inside the commutator was covered in a black ring of filth again....this was cleaned off by   (heres my tip )  sliding a piece of emery paper under the top bush and the commutator...then crank the engine over via the kickstart to clean the filth not start the engine !
these bushes where made from carbon,chocolate and swiss set ordered...just ground the old ones down for now....lasted for a 20 mile run and still charging ok !


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Re: dynamo part 2
« Reply #1 on: 30.01. 2009 21:12 »
15 or more years ago, I converted a Lucas m/cycle generator to 12v by having the field rewound, and substituting a 12v regulator for the 6v device (both Lucas). It worked, and is still working, very well.

Online groily

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Re: dynamo part 2
« Reply #2 on: 30.01. 2009 22:37 »
Good luck with the DVR frankenstein - I'm sure you'll find it works a treat (assuming the chocolate brushes hold up!) In my experience it's fit and forget with a DVR2, whether in 6 or 12v config. A serious contribution to reliable year-round riding.

Re converting dynamos to run at 12v, there should be no need for special effort these days - a standard-wound field and armature will produce quite enough volts to run and be regulated at 12v, although the cut-in speed goes up obviously. There are fine-wound '12v' field coils available (SRM, Feked etc in the UK) - and fine-wound '12v' armatures too - a combination which promises cut-in and voltage reg at the maker's engine rpm as for a '6v' system. This '12v' combination will offer the usual 60W output, continuous.
A standard E3L dynamo with a 12v regulator should deliver a reasonably safe 85-ish watts max. But there is more heat generated in the field coil at the speeds between when the cut-out cuts in and the regulator starts to regulate. If you keep the original '6v' armature and put in a fine-wound '12v' field coil, the maximum output soars, depending on the wire gauge and number of turns of the field coil winding. In theory, a '6v' wound armature with a '12v' field coil will produce up to 140W output at the same levels of heat dissipation you'd get with a standard 60W output at 6v - but the penalty is high engine rpm before cut-in happens and voltage regulation kicks in.

I currently have my A at 6v with a DVR2 and belt drive and 35W Halogen lamp - very good for what it is. And 2 other twins of other marques, both now with DVR2s. One has a bog-standard-wound armature and field coil, running at 12v with a 45W Halogen lamp, which it has done successfully for over 20 years and a serious mileage. It has in fact run for lengthy periods with a 60/55W halogen up front, which is talking proper illumination. Better with a DVR2 than with a previous (early) JG electronic regulator, and despite the heat dissipation question relating to the field coil, no problems provided one can live with the higher cut-in speed. I can, because I live in the middle of nowhere - but it also worked in London for a long time too. The other is an experiment, running a standard '6v' thick-wound armature with a '12v' fine-wound field winding - but the jury's out as it's very early days and the armature is an unknown quantity. Cut-in speed is very high compared with standard and this may well prove to have been a bad experiment even if the maximum safe output does turn out to be way above the norm for an E3L.