Bottle dynamo noise

I'm relatively new to bottle dynamos---previously I have only had hub
dynamos or battery lights---but I have one on my Brompton. Last night as I
picked up speed it suddenly mad a loud schreeching noise and the light
dimmed but didn't go out. As I slowed it eventually stopped. The noise as
pretty loud so I decided to switch just the LED lamp for the short journey
I was making. Also, it did this a bit towards the end of last winter but I
forgot about the problem over the summer. What is likely to be causing
this? Is it going to be as simple as replacing that little rubber ring or
is it more serious? It's a Nordlicht 2000.

Cheers,

Colin

Colin Blackburn writes:

I'm relatively new to bottle dynamos---previously I have only had
hub dynamos or battery lights---but I have one on my Brompton. Last
night as I picked up speed it suddenly mad a loud schreeching noise
and the light dimmed but didn't go out. As I slowed it eventually
stopped. The noise as pretty loud so I decided to switch just the
LED lamp for the short journey I was making. Also, it did this a
bit towards the end of last winter but I forgot about the problem
over the summer. What is likely to be causing this? Is it going to
be as simple as replacing that little rubber ring or is it more
serious? It's a Nordlicht 2000.

Has it slipped? If it has changed position so it's rolling at an
angle to the tyre, and maybe even touching the rim, that would
screech and lose efficiency.

If the position is still perfect, it could be worn internally
(though that takes a lot of miles).

Whatever it is, you're wise not to ride through it -- if it's just
positioning you could wear the ring badly, or if it's actually
slipping you could wear a flat on it.

Brendan
--
Brendan Halpin, Department of Sociology, University of Limerick, Ireland
Tel: w +353-61-213147 f +353-61-202569 h +353-61-390476; Room F2-025 x 3147
http://www.ul.ie/sociology/brendan.halpin.html

Colin Blackburn writes:

I'm relatively new to bottle dynamos---previously I have only had
hub dynamos or battery lights---but I have one on my Brompton. Last
night as I picked up speed it suddenly mad a loud schreeching noise
and the light dimmed but didn't go out. As I slowed it eventually
stopped. The noise as pretty loud so I decided to switch just the
LED lamp for the short journey I was making. Also, it did this a
bit towards the end of last winter but I forgot about the problem
over the summer. What is likely to be causing this? Is it going to
be as simple as replacing that little rubber ring or is it more
serious? It's a Nordlicht 2000.

Has it slipped? If it has changed position so it's rolling at an
angle to the tyre, and maybe even touching the rim, that would
screech and lose efficiency.

If the position is still perfect, it could be worn internally
(though that takes a lot of miles).

Whatever it is, you're wise not to ride through it -- if it's just
positioning you could wear the ring badly, or if it's actually
slipping you could wear a flat on it.

Brendan
--
Brendan Halpin, Department of Sociology, University of Limerick, Ireland
Tel: w +353-61-213147 f +353-61-202569 h +353-61-390476; Room F2-025 x 3147
http://www.ul.ie/sociology/brendan.halpin.html

Colin Blackburn wrote:

I'm relatively new to bottle dynamos---previously I have only had hub
dynamos or battery lights---but I have one on my Brompton. Last night as
I picked up speed it suddenly mad a loud schreeching noise and the light
dimmed but didn't go out. As I slowed it eventually stopped. The noise
as pretty loud so I decided to switch just the LED lamp for the short
journey I was making. Also, it did this a bit towards the end of last
winter but I forgot about the problem over the summer. What is likely to
be causing this? Is it going to be as simple as replacing that little
rubber ring or is it more serious? It's a Nordlicht 2000.

I suspect it's just slipping. Try increasing the contact force first,
then a new roller.

Colin Blackburn wrote:

I'm relatively new to bottle dynamos---previously I have only had hub
dynamos or battery lights---but I have one on my Brompton. Last night as
I picked up speed it suddenly mad a loud schreeching noise and the light
dimmed but didn't go out. As I slowed it eventually stopped. The noise
as pretty loud so I decided to switch just the LED lamp for the short
journey I was making. Also, it did this a bit towards the end of last
winter but I forgot about the problem over the summer. What is likely to
be causing this? Is it going to be as simple as replacing that little
rubber ring or is it more serious? It's a Nordlicht 2000.

I suspect it's just slipping. Try increasing the contact force first,
then a new roller.

On Thu, 09 Oct 2003 09:54:21 +0100, Colin Blackburn
wrote:

Last night as I
picked up speed it suddenly mad a loud schreeching noise and the light
dimmed but didn't go out.

I am pretty sure that the dynamo is slipping.


What is likely to be causing
this? Is it going to be as simple as replacing that little rubber ring or
is it more serious? It's a Nordlicht 2000.


I have three Nordlicht 2000s all set up the same on three different
bikes but one slips regardless of how careful I set it up. I have
swapped the three around the different bikes but the one bottle
continues to slip - I have even swapped the rubber rollers. The only
way I have found to stop it slipping is to use the metal roller rather
than the rubber one. Saddly the metal roller is very noisy.

John T.
Remove the singers of Spam before replying

On Thu, 09 Oct 2003 09:54:21 +0100, Colin Blackburn
wrote:

Last night as I
picked up speed it suddenly mad a loud schreeching noise and the light
dimmed but didn't go out.

I am pretty sure that the dynamo is slipping.


What is likely to be causing
this? Is it going to be as simple as replacing that little rubber ring or
is it more serious? It's a Nordlicht 2000.


I have three Nordlicht 2000s all set up the same on three different
bikes but one slips regardless of how careful I set it up. I have
swapped the three around the different bikes but the one bottle
continues to slip - I have even swapped the rubber rollers. The only
way I have found to stop it slipping is to use the metal roller rather
than the rubber one. Saddly the metal roller is very noisy.

John T.
Remove the singers of Spam before replying

On Thu, 09 Oct 2003 09:54:21 +0100, Colin Blackburn
wrote:

I'm relatively new to bottle dynamos---previously I have only had hub
dynamos or battery lights---but I have one on my Brompton. Last night as I
picked up speed it suddenly mad a loud schreeching noise and the light
dimmed but didn't go out. As I slowed it eventually stopped. The noise as
pretty loud so I decided to switch just the LED lamp for the short journey
I was making. Also, it did this a bit towards the end of last winter but I
forgot about the problem over the summer. What is likely to be causing
this? Is it going to be as simple as replacing that little rubber ring or
is it more serious? It's a Nordlicht 2000.


It'll be slipping. Was it raining at the time or had you been through
a puddle?

You get the (warning: ignorance of correct terms approaching) problem
that once the (static?) friction between the tyre and the drive wheel
is overcome, the drive wheel will slip like buggery until you get the
speed low enough that the (dynamic?) friction can move the drive wheel
again. Like locking a wheel on wet tarmac.


Do Nordlicht do an all weather roller? Check also that the dynamo is
correctly aligned - I use a bit of string tied to the wheel spindle
and pulled tight radially. Align the string over the dynamo and Sight
down it.


Tim
--
In space no one can eat ice cream

On Thu, 09 Oct 2003 09:54:21 +0100, Colin Blackburn
wrote:

I'm relatively new to bottle dynamos---previously I have only had hub
dynamos or battery lights---but I have one on my Brompton. Last night as I
picked up speed it suddenly mad a loud schreeching noise and the light
dimmed but didn't go out. As I slowed it eventually stopped. The noise as
pretty loud so I decided to switch just the LED lamp for the short journey
I was making. Also, it did this a bit towards the end of last winter but I
forgot about the problem over the summer. What is likely to be causing
this? Is it going to be as simple as replacing that little rubber ring or
is it more serious? It's a Nordlicht 2000.


It'll be slipping. Was it raining at the time or had you been through
a puddle?

You get the (warning: ignorance of correct terms approaching) problem
that once the (static?) friction between the tyre and the drive wheel
is overcome, the drive wheel will slip like buggery until you get the
speed low enough that the (dynamic?) friction can move the drive wheel
again. Like locking a wheel on wet tarmac.


Do Nordlicht do an all weather roller? Check also that the dynamo is
correctly aligned - I use a bit of string tied to the wheel spindle
and pulled tight radially. Align the string over the dynamo and Sight
down it.


Tim
--
In space no one can eat ice cream

Do Nordlicht do an all weather roller? Check also that the dynamo is
correctly aligned - I use a bit of string tied to the wheel spindle
and pulled tight radially. Align the string over the dynamo and Sight
down it.

Thanks for all the response. I'll check the alignment, check out for
rollers from Nordlicht and if all else fails go and see Ben at Kinetics to
get a SON fitted!

Colin