Charging resistance- help !!

[nevhunter]

Yes some are fixed .( Non adjustable.) but generally the three brush generator has the 3rd brush able to be moved. The maker has decided the desired current output on that type. The relay is called a cutout and is to prevent current running back through the generator when not operating It can fit anywhere between the output terminal and the battery but the original is in the end of the dynamo under the brass cover. I checked the 30 model headlamp switch. its like a coil spring in a circular recess formed to fit it in the switch body. You could get a length of fibre 1/8' x 1/2 x 2 1/2" and wind nichrome wire on it till you get the resistance you require. If you cut the charging current right back the battery will last longer and be less likely to overcharge and spill acid on your bike. If you put a decent wattage bulb in the tail light it will cancel out the low charge rate when you select" Park", as the resistance is bypassed on "full lights" selection only. Then you get the higher charge rate to handle the headlights being on. situation. Nev

[ian.scott]

It looks like the export models do have different dynamos and switches as all the british 3 brush dynamos i have seen are the same as mine with a built in 3rd brush and cutout or a fixed 3rd brush and cutout mounted in the headlight and dont have a P park position.

Ian

[nevhunter]

IF the 3rd brush is fixed you don't really need it. It could be eliminated and just use full generator voltage across the field with appropriate extra resistance in the circuit. The 3rd brush set up is fragile as the whole thing is quite delicate in those smallish generators. Some people put a diode in to regulate the earlier type generators. It can be remote and needs a heat sink, and should be large enough for the job. Nev