"WAYNE CHIRNSIDE" bravely wrote to "MIKE ROSS" (01 Sep
03  21:14:00)
 --- on the heady topic of "Re: Vehicle LED's"

 WC> When I was a kid my bicycle had a generator that was part of the
 WC> hub. Back in 1967 a 3 speed with this arrangement cost
 WC> somewhere around 100 dollars.
 WC> Far better than those little things that rub the tire.

How was the power taken out, insulated slip ring? I'm guessing it
required a lot of poles to generate any kind of power? Since the
rotational speed of a bicycle wheel is much slower than its radial
velocity, it must have been dim at slow speed, no?

Consider that 1mph is about 1.5ft/sec and a wheel periphery measures
about 7 ft, then 1 revolution/sec = 4.75mph, so 20mph is only about 4.2
rps or 252 rpm. A 60 hz generator needs turn at 3600rpm! Luckily with
the rim generator, the gear ratio is about 35:1 so in priciple at 20mph
it is generating at about 150Hz.

At 252 rpm the hub generator would require the equivalent of the gear or
35 poles. OTOH maybe there was a gearing system inside? Then it must
have used some really good metalurgy in the gears? Was there a way to
disengage the generator when not needed?

 Mike
 ****

... Batteries not included.
--- Blue Wave/DOS v2.30