Joined: Aug 2010
Posts: 12,688
Likes: 2,094
From: Madison, WI
Bikes: 1961 Ideor, 1966 Perfekt 3 Speed AB Hub, 1994 Bridgestone MB-6, 2006 Airnimal Joey, 2009 Thorn Sherpa, 2013 Thorn Nomad MkII, 2015 VO Pass Hunter, 2017 Lynskey Backroad, 2017 Raleigh Gran Prix, 1980s Bianchi Mixte on a trainer. Others are now gone.
I do not think there are any brushes in a bottle dynamo. Just spins a permanent magnet inside of a non-rotating armature with the windings. Can't get any simpler than that. I have never disassembled one, so maybe I have that backwards and the windings spin in perminent magnets? But that would be the hard way to build one.
The bottle dynamos I had (Union brand from Germany) had no holes to shoot in any tuner cleaner, they were supposed to be sealed against the weather.
I have never heard of any capacitors or diodes in them.