On 2018-02-24 13:51, AMuzi wrote:
On 2/24/2018 2:57 PM, Frank Krygowski wrote:
On 2/24/2018 2:57 PM, Joerg wrote:
On 2018-02-23 10:01, Tim McNamara wrote:


In my reference, generators mounted on the seatstay or
chainstays would
be "rear triangle" mounted. Because the frame is the
ground (earth on
the east side of the Atlantic), a single wire ran through
the frame
tubes. It connected to a carbon brush in the head tube,
which me
contact with an insulated ring on the steerer tube. A
wire from that
traveled through the front rack to the headlight.


And ground went via the bearings like it does in most
European dynamos set-ups? That was always a sick concept.
I don't think in automotive anyone would let a blooper
like that pass a design review. Yet that was and maybe
still is standard fare on most dynamo-equiped bicycles.

I agree that grounding via the bike frame is a bad idea. But
it's always been possible to run a two-conductor cord and
ground things properly, which is what I've done at least
since 1980.

And AFAIK all hub dynamos have always used proper grounding
through a two-conductor cord.


Right and a fascinating history, too.
When the British invented vehicle electric systems they had to pick a
number and six is a good number so they went with 6v.


That was not a British decision. At least in Europe all cars had 6V
system until the 60's.


... Positive Earth
too, which is a good name for a garage band or a cult.


A guy at my bike pub stop came on a vintage UK motorcycle. When looking
at it together he remarked the positive ground and said that in the
country of Her Royal Majesty they just had to be different. IIRC some
French cars had that as well. French? Mon Dieu!


... Anyway over time
(usually a few months) they discovered that linen wrapped single wire
passing through punched panel holes will let the essential smoke out, at
which point the car stops.


Seriously? On a motor vehicle? When I was young I wound some
transformers and when in need of a low voltage high amp secondary
winding it was customary to use raw copper and wrap it with
lacquer-soaked linen. The lacquer-soaking was crucial. That lasts almost
forever, I still have one that was built before WW-II. Of course, this
technique is not suitable for anything that moves, flexes or rattles.

This also saved money but it probably was detrimental to the health for
a hobbyist. The only way to get the lacquer off the hands were harsh
chemicals.


... So Sturmey Archer went with double wire.
Keeps the smoke in better. All was well after that.


Using the frame as ground is ok but not across bearings or bushings of
any kind.

--
Regards, Joerg

http://www.analogconsultants.com/