Dynamo lighting

In article <[email hidden]>,

PeteSig said:

Ray said:

Anything above walking pace has the lights flickering, ie walking with
your bike.
At 10km/h you have usable light, and you have easily reached full drive
by about 20km/h.

Keep It Simple Simon

Yes, I'd agree with that. I have no understanding of electronics - most of
the chat in this thread is like a foreign language to me. But that
description of your light sounds awfully like my B&M D'Lumotec Oval
http://www.bumm.de/index-e.html

I don't know why you'd go about making up a complex light when something
this good is about. With a hub dynamo you'd have enough output to run two of
these. I think they use a 3W Luxeon LED - not as bright as the Cree I know,
but damn good for any town and country road use.

Peter,

The need to reinvent the light is probably cost-driven or the desire to
be at the cutting edge of lighting design (ie being the first to use
these Cree lights when some of us are still trying to get the carbide
lamp lit).

Like you, my eyes glaze over when talk turns to wiggly-amps and things.
At least now I know I am not alone.

But, WRT the Lumotec, what is meant by a duplex wire? Does this just
mean two-core flex? If it is, I presume they do not want the bike frame
to be part of the circuit but to have the light and dynamo as a closed
circuit.

cheers,
Darryl

In aus.bicycle on Tue, 26 Jun 2007 02:44:08 GMT

20cents said:

But, WRT the Lumotec, what is meant by a duplex wire? Does this just
mean two-core flex? If it is, I presume they do not want the bike frame
to be part of the circuit but to have the light and dynamo as a closed
circuit.

Apparently in Germany the frame is often part of the circuit. When I
got the rear light for my dynamo hub, the instructions assumed that
you'd ground it via the frame, and noting that you could run earth to
the front light as well as active was an afterthought.

Zebee

20cents said:

In article <[email hidden]>,
"PeteSig" <[email hidden]> wrote:

Quoted message said:

But, WRT the Lumotec, what is meant by a duplex wire? Does this just
mean two-core flex? If it is, I presume they do not want the bike frame
to be part of the circuit but to have the light and dynamo as a closed
circuit.

cheers,
Darryl

Yep, some dynamo have a plug for a return wire (All dyno-hubs, most
modern french and german dynamos) and some don't (most asian dynamos)

The former is better as you don't need an electrical contact with the
frame which allows for the use inner tubes to make a bracket fit, or for
putting a dynamo light on your full carbon frame :-)

Cheers

Joel

--
Human Powered Cycles | High quality servicing and repairs
[email hidden] | Affordable second hand bikes
(03) 9029 6504 | Bicycle reuse centre
www.humanpowered.com.au | Mechanical and on-road training and instruction

20cents said:

The need to reinvent the light is probably cost-driven or the desire to
be at the cutting edge of lighting design (ie being the first to use
these Cree lights when some of us are still trying to get the carbide
lamp lit).

Ah, yes, the cutting edge. I had that once when I got my custom Cecil Walker
with the new 5 psd freehub, dishless wheel and 600ax crank and pedals.
Shimano dropped the ax pedal setup a couple of years later, leaving me in
the lurch. But I still have the bike - will ride it on the Audax 150km ride
this weekend.

A friend just asked me if I still have the Cateye CC 100 cycle computer of
the same vintage :-)

Quoted message said:

But, WRT the Lumotec, what is meant by a duplex wire? Does this just
mean two-core flex?

Yes

Quoted message said:

If it is, I presume they do not want the bike frame
to be part of the circuit but to have the light and dynamo as a closed
circuit.

Yes, I use a double-core wire to avoid any of the uncertainties of using the
frame as part of the circuit.

--
Cheers
Peter

~~~ ~ _@
~~ ~ _- \,
~~ (*)/ (*)

PeteSig said:

"20cents" wrote:

Quoted message said:

Quoted message said:

If it is, I presume they do not want the bike frame
to be part of the circuit but to have the light and dynamo as a
closed circuit.

Yes, I use a double-core wire to avoid any of the uncertainties of
using the frame as part of the circuit.

I know we are talking only a very small current here (<1 amp mostly) but
steering head bearings are not a good conductor, and the current buggers the
bearings.

Theo

PeteSig said:

20cents said:

The need to reinvent the light is probably cost-driven or the desire to
be at the cutting edge of lighting design (ie being the first to use
these Cree lights when some of us are still trying to get the carbide
lamp lit).

Ah, yes, the cutting edge. I had that once when I got my custom Cecil Walker
with the new 5 psd freehub, dishless wheel and 600ax crank and pedals.
Shimano dropped the ax pedal setup a couple of years later, leaving me in
the lurch. But I still have the bike - will ride it on the Audax 150km ride
this weekend.

In Crankin Cycles bike shop in Collie there is an old bike with Shimano
Dura-Ace AX everything. Ax seatpost, brakes, the whole lot. It looked in
pretty good nick for it's age. I remember being impressed by the aero AX
waterbottle when I saw one many years ago.

Friday

Joel Mayes said:

20cents said:

In article <[email hidden]>,
"PeteSig" <[email hidden]> wrote:

Quoted message said:

But, WRT the Lumotec, what is meant by a duplex wire? Does this just
mean two-core flex? If it is, I presume they do not want the bike frame
to be part of the circuit but to have the light and dynamo as a closed
circuit.

cheers,
Darryl

Yep, some dynamo have a plug for a return wire (All dyno-hubs, most
modern french and german dynamos) and some don't (most asian dynamos)

The former is better as you don't need an electrical contact with the
frame which allows for the use inner tubes to make a bracket fit, or for
putting a dynamo light on your full carbon frame :-)

Cheers

Joel

I've measured the resistance of carbon fibres and they are amazingly
good conductors, you'd have no trouble using carbon fibre to power
things, It's only the epoxy which is non-conductive. The guy that built
my carbon fibre kayak changed to pneumatic cutting and shaping tools
after he kept getting shocks from electrical tools when the carbon
strands connected with live bits.

Do you spell it fiber or fibre? I prefer fibre.

Friday

On 2007-06-26, Friday (aka Bruce)
was almost, but not quite, entirely unlike tea:

Quoted message said:

Joel Mayes said:

Yep, some dynamo have a plug for a return wire (All dyno-hubs, most
modern french and german dynamos) and some don't (most asian dynamos)

The former is better as you don't need an electrical contact with the
frame which allows for the use inner tubes to make a bracket fit, or for
putting a dynamo light on your full carbon frame :-)

Electrical contact -> corrosion?

Quoted message said:

I've measured the resistance of carbon fibres and they are amazingly
good conductors, you'd have no trouble using carbon fibre to power
things, It's only the epoxy which is non-conductive. The guy that built
my carbon fibre kayak changed to pneumatic cutting and shaping tools
after he kept getting shocks from electrical tools when the carbon
strands connected with live bits.

Does he want a laser? I've got a 125mW laser.

Quoted message said:

Do you spell it fiber or fibre? I prefer fibre.

Brgh. Gah. Damn Americans.

--
TimC
I was going to compile a list of innovations that could be
attributed to Microsoft. Once I realized that Ctrl-Alt-Del
was handled in the BIOS, I found that there aren't any. --unknown

In article <slrn-0.9.7.4-10122-8530-200706262310-
[email hidden]>, [email hidden]-
astro.swin.edu.au says...

Quoted message said:

On 2007-06-26, Friday (aka Bruce)

Quoted message said:

Do you spell it fiber or fibre? I prefer fibre.

Brgh. Gah. Damn Americans.

I'm not sure how to gage that response!

Friday said:

Joel Mayes said:

20cents said:

In article <[email hidden]>,
"PeteSig" <[email hidden]> wrote:

Quoted message said:

But, WRT the Lumotec, what is meant by a duplex wire? Does this just
mean two-core flex? If it is, I presume they do not want the bike frame
to be part of the circuit but to have the light and dynamo as a closed
circuit.

cheers,
Darryl

Yep, some dynamo have a plug for a return wire (All dyno-hubs, most
modern french and german dynamos) and some don't (most asian dynamos)

The former is better as you don't need an electrical contact with the
frame which allows for the use inner tubes to make a bracket fit, or for
putting a dynamo light on your full carbon frame :-)

I've measured the resistance of carbon fibres and they are amazingly
good conductors, you'd have no trouble using carbon fibre to power
things, It's only the epoxy which is non-conductive. The guy that built
my carbon fibre kayak changed to pneumatic cutting and shaping tools
after he kept getting shocks from electrical tools when the carbon
strands connected with live bits.

Do you spell it fiber or fibre? I prefer fibre.

Friday

That's quite interesting, I'm sure I remember carbon being a poor
conductor from my high-school chemistry days.

Cheers

Joel 'fibre is how I spell fibre' Mayes

--
Human Powered Cycles | High quality servicing and repairs
[email hidden] | Affordable second hand bikes
(03) 9029 6504 | Bicycle reuse centre
www.humanpowered.com.au | Mechanical and on-road training and instruction

Joel Mayes said:

That's quite interesting, I'm sure I remember carbon being a poor
conductor from my high-school chemistry days.

Compared to silver or copper, yes. Compared to water, sand, wood, rubber,
carbon is an excellent conductor.

Theo

Joel Mayes said:

That's quite interesting, I'm sure I remember carbon being a poor
conductor from my high-school chemistry days.

The positive electrode of a zinc-carbon cell (the common variety of battery) is a carbon rod. So I wouldn't describe it as being poor. But then it isn't any where near as good as common metals. It also depends greatly on the form of carbon. From memory diamond insulates very well, but I don't think they had any diamonds in the high school chemistry lab for us to test. Graphite allows much better electron movement, so conducts better. Resistors are generally made of carbon or a metal film.

Theo Bekkers said:

Joel Mayes said:

That's quite interesting, I'm sure I remember carbon being a poor
conductor from my high-school chemistry days.

Compared to silver or copper, yes. Compared to water, sand, wood, rubber,
carbon is an excellent conductor.

It also depends on the form of the carbon. Graphite is a reasonable
conductor. Diamond is a pretty decent insulator.

--
My Usenet From: address now expires after two weeks. If you email me, and
the mail bounces, try changing the bit before the "@ to usenet".

On 2007-06-27, ghostgum (aka Bruce)
was almost, but not quite, entirely unlike tea:

Quoted message said:

Joel Mayes said:

That's quite interesting, I'm sure I remember carbon being a poor
conductor from my high-school chemistry days.

It's not that poor, although I have always enjoyed getting an 80 amp
power supply, and making a pencil glow redhot before it bursts into
flames. The pencil, not the powersupply. Although I did once watch
as a over temperature, over current, over, under and reverse voltage,
short circuit, etc protected stepper motor controller became redhot
before emitting the magic smoke. Merely as two of the motor wires
brushed up against each other.

Still, if a frame presents a few ohms, that's large enough such that
you wouldn't want to do that. An amp across your bike frame will
generate a few volts, hence a few watts of lossage. I donut
understand why people are so cheap with wires (I really donut get
wireless computers)

Quoted message said:

The positive electrode of a zinc-carbon cell (the common variety of
battery) is a carbon rod. So I wouldn't describe it as being poor.
But then it isn't any where near as good as common metals. It also
depends greatly on the form of carbon. From memory diamond insulates
very well, but I don't think they had any diamonds in the high school
chemistry lab for us to test.

Diamond makes for excellent heat conductors -- hence their current
investigation in fast CPUs to transmit the heat from the transistors
directly to the heatsink.

--
TimC
Cult: (n) a small, unpopular religion.
Religion: (n) a large, popular cult.

Theo Bekkers said:

Joel Mayes said:

That's quite interesting, I'm sure I remember carbon being a poor
conductor from my high-school chemistry days.

Compared to silver or copper, yes. Compared to water, sand, wood, rubber,
carbon is an excellent conductor.

Yes, the glare of arc lighting.
Rather sad about progress in that area.

Theo Bekkers said:

Compared to silver or copper, yes. Compared to water, sand, wood, rubber,
carbon is an excellent conductor.

That depends very much on the form it's in.

--
Home page: http://members.westnet.com.au/mvw

Michael Warner said:

Theo Bekkers said:

Compared to silver or copper, yes. Compared to water, sand, wood, rubber,
carbon is an excellent conductor.

That depends very much on the form it's in.

The discussion was about carbon fiber bike frames, so we know what form
it's in.

Dorfus