What bulb for dynamo.

On Tue, 12 Jul 2005 23:19:16 GMT, "ian henden" <[email hidden]>

Quoted message said:

Quoted message said:

Quoted message said:

if you put electricity through
*lamps*, then they glow. Bulbs *grow*.

Quoted message said:

Quoted message said:

Ah, Henden-san correctry identifies that Shimano burrbs grow very
brightry.
Phirrips burrbs also grow brightry, also rast ronger.

Quoted message said:

Which post demonstrates that Guy is a [censored].

Which post demonstrates that Henden is a humourless git :-D

Guy
--
May contain traces of irony. Contents liable to settle after posting.
http://www.chapmancentral.co.uk

88% of helmet statistics are made up, 65% of them at CHS, Puget Sound

Steven said:

On Wed, 13 Jul 2005 10:35:35 +0100, "Clive George" <[email hidden]>

Quoted message said:

"Steven" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

A wattage rating for a dynamo is an indication of its maximum output
(0.5amps at
6volts).

You *cannot* damage a 6v 2.4w lamp by running on a generator with an
output of
6v. The resistance of the lamp (15 ohms) will limit the current to 0.4
amps.

Tried this?

No, because it never occured to me that someone selling a 0.5 amp device would
specify its output using two almost completely erroneous units.

When I was at school, a policeman came to give us a talk on bike safety, and
told us never to use dynamo lamps as they were dangerous. He related the story
of a girl who'd been killed because she was using dynamo lights.

"Even though we shouted a warning, she cycled towards us with the
dynamo, and we believed she was ready to use it! It was a split-second
decision, but we had to take her down. I blame the people who deal
dynamos to these kids. It's only a small step from a dynamo to carrying
a mended table leg!"

- extract from Policeman A's evidence given at the public inquiry into
the menace of dangerous bike dynamos.

--
Joe * If I cannot be free I'll be cheap

On Tue, 12 Jul 2005 22:28:38 +0100, Tony Raven <[email hidden]>

Quoted message said:

bulb: the glass of an electric light
lamp: any structure containing a source of artificial light.

Yup, that's the definition I've always used. Drummed into me from an
early age, in fact, by a father whose job was lecturer in electrical
engineering...

Guy
--
May contain traces of irony. Contents liable to settle after posting.
http://www.chapmancentral.co.uk

88% of helmet statistics are made up, 65% of them at CHS, Puget Sound

On Tue, 12 Jul 2005 23:16:09 GMT, "ian henden" <[email hidden]>

Quoted message said:

This, of course, is why dynamo lamps still work at quite low speed. But not
when stationary - you ought to switch over to battery backup when stopped.

Unless you have standlights. Which I do.

Guy
--
May contain traces of irony. Contents liable to settle after posting.
http://www.chapmancentral.co.uk

88% of helmet statistics are made up, 65% of them at CHS, Puget Sound

Clive George said:

I got my first dynamo when I was still riding to school (I think - I don't
think it was before then, I had traditional battery lamps). I don't get on
with batteries...

My sister had a dynamo. It was [censored] (but this was a cheapish Halfords
one in the 1970s, so not *that* surprising), but, more to the point, I
had a Raleigh Olympus and "racing" bikes didn't have dynamos!

And later, when I graduated to a proper tourer, I was quite adamant that
no bike of mine would ever have a dynamo or a prop stand. When I bought
the Streetmachine I asked about to see what extras to get, and everyone
said the dynohub lighting and stand... Time for a rethink, and following
the Streetmachine's example my main 3 bikes now all have dynamo lighting
and stands. Bothers me a bit I'd been just so *wrong* about what I
thought was best for me, but it's sorted now.

Pete.
--
Peter Clinch Medical Physics IT Officer
Tel 44 1382 660111 ext. 33637 Univ. of Dundee, Ninewells Hospital
Fax 44 1382 640177 Dundee DD1 9SY Scotland UK
net [email hidden] http://www.dundee.ac.uk/~pjclinch/

Just zis Guy said:

On Tue, 12 Jul 2005 23:08:33 GMT, "ian henden" <[email hidden]>

Quoted message said:

Quoted message said:

The word "bulb" refers to the shape, seeds grow, bulbs are just bulb
shaped.

Quoted message said:

Not to an electrical engineer.
Bulbs grow, Lamps glow.

Where did you study electrical engineering? By a curious coincidence,
my BEng was earned at the University of Southampton, a town of which I
understand you have some first-hand knowledge :-)

Ian studied electrical engineering at Southampton by a strange
coincidence - under the bonnet of a broken down Solent Blue Line ;-)

--
Tony

"I did make a mistake once - I thought I'd made a mistake but I hadn't"
Anon

Simon Brooke said:

When seeking to correct other people, first check that you are
right. Otherwise you may appear to be an ignorant [censored].

Are you suggesting that Henden might only *appear* to be an ignorant
[censored]? ;-)

Guy
--
May contain traces of irony. Contents liable to settle after posting.
http://www.chapmancentral.co.uk

88% of helmet statistics are made up, 65% of them at CHS, Puget Sound

Clive George said:

Bike dynamos aren't typically generators with an output of 6v, despite what
that wattage rating claims. Roughly speaking they're generators with an
output of 0.5A.

<pedant> Alternators, strictly speaking </pedant>

Guy
--
May contain traces of irony. Contents liable to settle after posting.
http://www.chapmancentral.co.uk

88% of helmet statistics are made up, 65% of them at CHS, Puget Sound

Just zis Guy said:

Are you suggesting that Henden might only *appear* to be an ignorant
[censored]? ;-)

He might just be a [censored]. He wouldn't /have/ to be ignorant.

Pete.
--
Peter Clinch Medical Physics IT Officer
Tel 44 1382 660111 ext. 33637 Univ. of Dundee, Ninewells Hospital
Fax 44 1382 640177 Dundee DD1 9SY Scotland UK
net [email hidden] http://www.dundee.ac.uk/~pjclinch/

On Wed, 13 Jul 2005 10:03:45 GMT, [email hidden] (Steven)

Quoted message said:

When I was at school, a policeman came to give us a talk on bike safety, and
told us never to use dynamo lamps as they were dangerous. He related the story
of a girl who'd been killed because she was using dynamo lights.

In matters of bicycle lighting, the Police are strictly armatures.
And that information is no longer current anyway.

The girl was taken down by terrorists from Dura, a notorious cell.
May the SON never shine on them! They are the nexus of a movement
that can't stand light. Wire we still putting up with these people?
We should not be generating publicity for their cores, we should be
ever ready for resistance to do watts right... [cont. p94]

Guy
--
May contain traces of irony. Contents liable to settle after posting.
http://www.chapmancentral.co.uk

88% of helmet statistics are made up, 65% of them at CHS, Puget Sound

On Wed, 13 Jul 2005 11:13:38 +0100, "Clive George" <[email hidden]>

Quoted message said:

"Steven" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

No, because it never occured to me that someone selling a 0.5 amp device
would
specify its output using two almost completely erroneous units.

Well, to be fair to the makers of these things, the units are a fair
approximation, and as long as you follow the instructions (ie put a 3W bulb
in if you're only using a front lamp), it works. It's an interesting example
of the way a little knowledge is a dangerous thing :-)

They sound very dangerous to me. Someone inherits a bike with a dynamo. Next
year they go out in the dark and their front light blows. They look behind and
see the rear glowing strongly so believe they are visible from the read. A
little later ...

Now, the "I'm such a perfect human being" brigade will say it's entirely the
rider's fault because they shouldn't be riding without a working front light,
but in reality, most people wouldn't get off and walk in current non-rural
conditions just because their front light was broken.

Quoted message said:

Quoted message said:

When I was at school, a policeman came to give us a talk on bike safety,
and
told us never to use dynamo lamps as they were dangerous. He related the
story
of a girl who'd been killed because she was using dynamo lights.

Some kind of pro-ever-ready assasination squad? Or was it because dynamos
are typically German so the local BNP did her?

No, standard motorist.

She'd pulled up at a T junction ready to turn right and a motorist, taking the
corner just a little wide went stright into her. She was completely invisible
until just before she was hit.

"Steven" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

Quoted message said:

Quoted message said:

No, because it never occured to me that someone selling a 0.5 amp device
would
specify its output using two almost completely erroneous units.

Well, to be fair to the makers of these things, the units are a fair
approximation, and as long as you follow the instructions (ie put a 3W
bulb
in if you're only using a front lamp), it works. It's an interesting
example
of the way a little knowledge is a dangerous thing :-)

They sound very dangerous to me.

Oh dear - are you aware of how careless these words are? Remember, to a lot
of people riding a bike in the primary position sounds very dangerous - yet
AFAIR you know as well as the rest of us that it's actually the safe thing
to do in a lot of situations.

Quoted message said:

Someone inherits a bike with a dynamo. Next
year they go out in the dark and their front light blows. They look behind
and
see the rear glowing strongly so believe they are visible from the read. A
little later ...

You may be surprised how little later - if the front one goes, the back one
will die before you get to look round! (BTDT)

Of course this is no longer such a problem these days. Various solutions
exist - mostly involving voltage limiters. Lots of lights use these these
days. My version involves having the rear lamp in series with the front, so
they can only work together (the back is LED so it won't blow). One of the
most common is to just use the 'mo for the front - rear LED battery lights
are pretty good these days, and battery life is close to not being a problem
even for me! (not close enough though :-) )
While I still used bulbs in the back, I used 0.15A rather than 0.1A bulbs -
these seemed a little bit more robust, which was good.

Quoted message said:

Quoted message said:

Quoted message said:

When I was at school, a policeman came to give us a talk on bike safety,
and
told us never to use dynamo lamps as they were dangerous. He related the
story
of a girl who'd been killed because she was using dynamo lights.

Some kind of pro-ever-ready assasination squad? Or was it because dynamos
are typically German so the local BNP did her?

No, standard motorist.

She'd pulled up at a T junction ready to turn right and a motorist, taking
the
corner just a little wide went stright into her. She was completely
invisible
until just before she was hit.

It's quite likely she'd have been hit if she had a front battery lamp - the
motorist wasn't looking where they were going. Bikes aren't completely
invisible to motorists, even in the dark - they've got headlamps.

And the correct advice in this situation is not 'don't use dynamos', but 'be
aware that they don't work when you're stopped'. Suitable road positioning
helps here - and in this case, it's not the primary position!

cheers,
clive

in message <[email hidden]>, Just zis Guy,

you know? (') said:

Simon Brooke said:

When seeking to correct other people, first check that you are
right. Otherwise you may appear to be an ignorant [censored].

Are you suggesting that Henden might only *appear* to be an ignorant
[censored]? ;-)

Yup. I'm not an ignorant [censored], I just play one in Real Life.

--
[email hidden] (Simon Brooke) http://www.jasmine.org.uk/~simon/
; ... of course nothing said here will be taken notice of by
; the W3C. The official place to be ignored is on www-style or
; www-html. -- George Lund

in message <[email hidden]>, Steven

(') said:

Clive George said:

"Steven" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

No, because it never occured to me that someone selling a 0.5 amp
device would
specify its output using two almost completely erroneous units.

Well, to be fair to the makers of these things, the units are a fair
approximation, and as long as you follow the instructions (ie put a 3W
bulb in if you're only using a front lamp), it works. It's an
interesting example of the way a little knowledge is a dangerous thing
:-)

They sound very dangerous to me. Someone inherits a bike with a dynamo.
Next year they go out in the dark and their front light blows. They
look behind and see the rear glowing strongly so believe they are
visible from the read. A little later ...

Now, the "I'm such a perfect human being" brigade will say it's
entirely the rider's fault because they shouldn't be riding without a
working front light, but in reality, most people wouldn't get off and
walk in current non-rural conditions just because their front light was
broken.

Which is what the spare bulbs neatly wrapped in soft cloth and carried in
a used 35mm film can in your bag are for.

You can't protect people from being stupid, and nor should you.

Quoted message said:

Quoted message said:

Some kind of pro-ever-ready assasination squad? Or was it because
dynamos are typically German so the local BNP did her?

No, standard motorist.

She'd pulled up at a T junction ready to turn right and a motorist,
taking the corner just a little wide went stright into her. She was
completely invisible until just before she was hit.

Well, that's 100% bad driving on the part of the motorist, isn't it? What
part of '... you can see to be clear' do you not understand?

--
[email hidden] (Simon Brooke) http://www.jasmine.org.uk/~simon/

'Victories are not solutions.'
;; John Hume, Northern Irish politician, on Radio Scotland 1/2/95
;; Nobel Peace Prize laureate 1998; few have deserved it so much

On Wed, 13 Jul 2005 11:47:57 GMT, [email hidden] (Steven)

Quoted message said:

They sound very dangerous to me. Someone inherits a bike with a dynamo. Next
year they go out in the dark and their front light blows. They look behind and
see the rear glowing strongly so believe they are visible from the read. A
little later ...

....they crash into a signpost. Meanwhile, back in the 21st Century,
dynamo rear lights are built with LEDs not filament lamps and both
front and rear are fitted with Zeners and standlights.

Quoted message said:

Now, the "I'm such a perfect human being" brigade will say it's entirely the
rider's fault because they shouldn't be riding without a working front light,
but in reality, most people wouldn't get off and walk in current non-rural
conditions just because their front light was broken.

I probably would, actually, but as others have suggested is common
practice I also carry a couple of spare lamps in my toolkit, plus I
always have at least two lights at each end of the bike.

Quoted message said:

Quoted message said:

Quoted message said:

When I was at school, a policeman came to give us a talk on bike safety,
and
told us never to use dynamo lamps as they were dangerous. He related the
story
of a girl who'd been killed because she was using dynamo lights.

Quoted message said:

She'd pulled up at a T junction ready to turn right and a motorist, taking the
corner just a little wide went stright into her. She was completely invisible
until just before she was hit.

Ah, so it was the motorist's fault for failing to drive within the
distance they could see to be clear (and probably taking the corner
too fast as well, if they were that far over the line). Thanks for
clearing that up.

I'm sure if they'd hit a tree it would have been "the tree's fault"...

Guy
--
May contain traces of irony. Contents liable to settle after posting.
http://www.chapmancentral.co.uk

88% of helmet statistics are made up, 65% of them at CHS, Puget Sound

Simon Brooke said:

Quoted message said:

Now, the "I'm such a perfect human being" brigade will say it's
entirely the rider's fault because they shouldn't be riding without a
working front light, but in reality, most people wouldn't get off and
walk in current non-rural conditions just because their front light was
broken.

Which is what the spare bulbs neatly wrapped in soft cloth and carried in
a used 35mm film can in your bag are for.

As I said, the "I'm so perfect" mob will be off on one. Didn't take long.

Quoted message said:

You can't protect people from being stupid, and nor should you.

An interesting view of public safety, but not one that I think would commend you
the relatives of all the people who would die as a result of following policies
based on it.

To let you into a little secret, I don't think you are *quite* as proof against
the occasional act of stupidity as you think you are.

Quoted message said:

Well, that's 100% bad driving on the part of the motorist, isn't it? What
part of '... you can see to be clear' do you not understand?

What has my understanding got to do with it?

I was a seven year old child at the time, and not allowed to drive cars.

You do realise that your continued self-righteous, sanctimonious prattle marks
you out as little better than a moron when it comes to responsible road safety
measures?

you know? said:

On Wed, 13 Jul 2005 10:03:45 GMT, [email hidden] (Steven)

Quoted message said:

When I was at school, a policeman came to give us a talk on bike safety, and
told us never to use dynamo lamps as they were dangerous. He related the story
of a girl who'd been killed because she was using dynamo lights.

In matters of bicycle lighting, the Police are strictly armatures.
And that information is no longer current anyway.

Armatures? Current? You're alternating between sense and nonsense.

--
Nobby

Simon Brooke said:

in message <[email hidden]>, Steven
([email hidden]'😉 wrote:

[snip]

Quoted message said:

Quoted message said:

She'd pulled up at a T junction ready to turn right and a motorist,
taking the corner just a little wide went stright into her. She was
completely invisible until just before she was hit.

Had a very similar near miss myself some years ago. Dark night but
street lamps present, usual stream of vehicles leaving the work car
park, rode along the minor road to the T-junction. I'm waiting to turn
right, cars on my left going left, a car comes along the main road from
my left to turn right off the main road. The driver cuts the corner, so
he drives straight at me. How exactly the car missed me I'm not sure. I
leant sideways (no time for anything else), maybe the car swerved. It
stopped 30 or 40 yards down the road. The driver was completely
convinced there had been a substantial collision. I felt the car go
past, whether it made slight physical contact or it was just the
slipstream I cannot say.

Neither can I say if anything different would have happened if I had
been using battery lights instead of my dynamo. Given the huge
difference in the power of car lights compared to bike lights, I wonder
if the driver could see anything much other than the car headlights
waiting to come out of the side road.

Quoted message said:

Well, that's 100% bad driving on the part of the motorist, isn't it? What
part of '... you can see to be clear' do you not understand?

Yes, it was, in my example too. He cut the corner. How much this would
have comforted me if I had been killed you can probably guess.

--
Joe * If I cannot be free I'll be cheap

"Steven" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

Yes, it's true that the motorist probably did share the blame, but the
fact
remains that the little girl died *because her dynamo light wasn't
working*.

(And any suggestion as per Clive George that she'd probably have been hit
anyway
is pretty stupid, because it's effectively saying that 'be seen' lights
are
irrelevant because you'll get hit anyway since a motorist should be able
to see
you without lights, and if he can't, he probably wouldn't be able to see
you
with them.)

....

Quoted message said:

You were so keen to get this message accross that you lost the plot and
started
hitting out wildly in a frankly absurd attempt to make out that the system
had
not failed in a tragedy that took place at least 40, and probably 50 years
ago.

Thanks for giving me a timescale. I'm afraid that probably supports my view
that she'd have probably been hit anyway. Battery lights then were [censored].

The problem is 'being seen' lights don't work very well from the side in the
way that the dead girl needed them to. That's mostly ok, since the danger
they help with is mostly from the front (eg cars pulling out on you).

clive

On Wed, 13 Jul 2005 18:16:43 +0100, "Clive George" <[email hidden]>

Quoted message said:

"Steven" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

Yes, it's true that the motorist probably did share the blame, but the
fact
remains that the little girl died *because her dynamo light wasn't
working*.

(And any suggestion as per Clive George that she'd probably have been hit
anyway
is pretty stupid, because it's effectively saying that 'be seen' lights
are
irrelevant because you'll get hit anyway since a motorist should be able
to see
you without lights, and if he can't, he probably wouldn't be able to see
you
with them.)

...

Quoted message said:

You were so keen to get this message accross that you lost the plot and
started
hitting out wildly in a frankly absurd attempt to make out that the system
had
not failed in a tragedy that took place at least 40, and probably 50 years
ago.

Thanks for giving me a timescale. I'm afraid that probably supports my view
that she'd have probably been hit anyway. Battery lights then were [censored].

Clive, that's complete and utter bollocks.

If your contention were correct, no one would have cycled at night, because most
roads were unlit, and according to your hypothosis everyone would have got
knocked down every time thy had to stop at a T junction to await a car turning
into the road they were turning out of.

This just didn't happen, at least not to the extent that your theory would
suppose.

Quoted message said:

The problem is 'being seen' lights don't work very well from the side in the
way that the dead girl needed them to. That's mostly ok, since the danger
they help with is mostly from the front (eg cars pulling out on you).

They threw a pool of light into the road ahead of the cyclist, and that is what
a motorist would see as his clue to there being someone there. Car headlights
were puny in those days and you could more easily see other dimmer lights.

Your theory is interesting, but just doesn't fit in with the road casualty
statistics.