On Sun, 22 Mar 1998 16:39:00 -0500 Daniel C Williams (danwilms "at" tiac.net) writes:
>Chris L Johnson wrote:
>>
>> I posted some time ago a solution for simplified wiring for the `96
>> Fantic Section - and other bikes extrapolated. The simplified
>>scheme removed all but the fan diode/regulator power modifying thing. The
>>system worked well, but I have noticed a problem on my bike... I am now
>>suggesting you add the voltage regulator back into the wiring scheme.

...To which Dan Williams gave the following excellent and knowledgeable reply. This one gets hard copied to my technical file (and copied to the list), Thanks Dan! I'm just a mechanical engineer who doesn't know squat about electrical intricacies beyond what I've learned from experimentation. Things work for me or are found to not work in all cases...thanks for the "why" of the matter.

>There are usually two components Chris. A rectifier bridge which is an
>array of four diodes to convert the ac to dc. This dc isn't so hot for
>a motor though as the rectifier essentially changes the polarity of one
>half of the sine wave out of the magneto. The regulator has two
>functions. One is to act as a low pass filter to smooth out the dc
>from the rectifier. The other thing the regulator does is act as a peak
>limiter to prevent the dc voltage from going too high.
>
>Without the rectifier the regulator is looking at an ac voltage that
>may reverse bias the filter capacitors and damage them. Your regulator
>probably has diodes built in to protect the filter components but
>these would only give a half wave rectifier and therefore alot less power
>for the fan, possibly not enough to start it in all conditions.
>
>Without the regulator you are supplying a pulsed signal to the fan
>which would make its operation unpredictable. You also run the (low)
>risk of supplying peak voltages in excess of the fan's capacity.
>The fan is mostly a series inductor (coil) so it has an inherent low pass
>filter built in but it's not anywhere near as efficient as the
>regulator.
>
>I believe the finned thingy you refer to is a germanium rectifier but
>I could be wrong.
>
>Regards
>Dan
>

Chris (CJ) Johnson
Director of Engineering,
College Park Industries, Inc.
(810) 294-7950 (at CPI), (616) 664-4173 (home office)
papazit "at" juno.com