Dynamo lighting



2

20cents

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

> "Ray" wrote:
> > 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
 
Z

Zebee Johnstone

Guest
In aus.bicycle on Tue, 26 Jun 2007 02:44:08 GMT
20cents <[email protected]> wrote:
> 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
 
J

Joel Mayes

Guest
On 2007-06-26, 20cents <[email protected]> wrote:
> In article <[email protected]>,
> "PeteSig" <[email protected]> wrote:


> 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 protected] | Affordable second hand bikes
(03) 9029 6504 | Bicycle reuse centre
www.humanpowered.com.au | Mechanical and on-road training and instruction
 
P

PeteSig

Guest
"20cents" wrote:

> 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 :)

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


Yes

> 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

~~~ ~ [email protected]
~~ ~ _- \,
~~ (*)/ (*)
 
T

Theo Bekkers

Guest
PeteSig wrote:
> "20cents" wrote:


>> 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
 
F

Friday

Guest
PeteSig wrote:
> "20cents" wrote:
>
>> 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
 
F

Friday

Guest
Joel Mayes wrote:
> On 2007-06-26, 20cents <[email protected]> wrote:
>> In article <[email protected]>,
>> "PeteSig" <[email protected]> wrote:

>
>> 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
 
T

TimC

Guest
On 2007-06-26, Friday (aka Bruce)
was almost, but not quite, entirely unlike tea:
> Joel Mayes wrote:
>> 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?

> 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.

> 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
 
R

Ray

Guest
In article <slrn-0.9.7.4-10122-8530-200706262310-
[email protected]>, [email protected]-
astro.swin.edu.au says...
> On 2007-06-26, Friday (aka Bruce)
>
> > Do you spell it fiber or fibre? I prefer fibre.

>
> Brgh. Gah. Damn Americans.
>

I'm not sure how to gage that response!
 
J

Joel Mayes

Guest
On 2007-06-26, Friday <[email protected]> wrote:
> Joel Mayes wrote:
>> On 2007-06-26, 20cents <[email protected]> wrote:
>>> In article <[email protected]>,
>>> "PeteSig" <[email protected]> wrote:

>>
>>> 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 protected] | Affordable second hand bikes
(03) 9029 6504 | Bicycle reuse centre
www.humanpowered.com.au | Mechanical and on-road training and instruction
 
T

Theo Bekkers

Guest
Joel Mayes wrote:

> 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
 

ghostgum

New Member
Aug 30, 2005
245
0
0
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.
 
S

Stuart Lamble

Guest
On 2007-06-27, Theo Bekkers <[email protected]> wrote:
> Joel Mayes wrote:
>
>> 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".
 
T

TimC

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

> 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.
 
T

Terryc

Guest
Theo Bekkers wrote:
> Joel Mayes wrote:
>
>
>>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.
 
M

Michael Warner

Guest
On Thu, 28 Jun 2007 07:44:33 +0800, Theo Bekkers wrote:

> 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
 
D

Dorfus Dippintush

Guest
Michael Warner wrote:
> On Thu, 28 Jun 2007 07:44:33 +0800, Theo Bekkers wrote:
>
>> 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