Hi,

we have a floor lamp that makes the room far too bright when on, and
leaves the room too dark when off. So, we asked our unreliable
handyman to fit a dimmer switch, which he did, a normal click on/off
dimmer in a plastic housing, by cutting the main cord, and putting it
inbetween the plug and lamp.

He left the job muttering something about "it buzzes because there is
no earth". The thing did buzz, and the lamp flickered as well, and
eventually after a week or so, there was a reasonbly loud bang, and the
lamp stopped working.

How do I do this properly without the above problems?

Many thanks
Colin

I've fitted in cheap Ikea in-line dimmers to table lamps with no earth
connections, and no problems. Can't see the problem..

In article .com
, writes
Hi,

we have a floor lamp that makes the room far too bright when on, and
leaves the room too dark when off. So, we asked our unreliable
handyman to fit a dimmer switch, which he did, a normal click on/off
dimmer in a plastic housing, by cutting the main cord, and putting it
inbetween the plug and lamp.

He left the job muttering something about "it buzzes because there is
no earth". The thing did buzz, and the lamp flickered as well, and
eventually after a week or so, there was a reasonbly loud bang, and the
lamp stopped working.

The buzzing has nothing to do with the earth, it's a symptom of a ****
dimmer with a loosely wound inductive filter. As to the failure, is the floor
lamp a halogen uplighter perhaps? If so, your dimmer may require to be
derated quite a bit for the linear halogen bulb, perhaps a 400W dimmer for
a 250W bulb.
--
fred
Plusnet - I hope you like vanilla

wrote:
Hi,

we have a floor lamp that makes the room far too bright when on, and
leaves the room too dark when off. So, we asked our unreliable
handyman to fit a dimmer switch, which he did, a normal click on/off
dimmer in a plastic housing, by cutting the main cord, and putting it
inbetween the plug and lamp.

He left the job muttering something about "it buzzes because there is
no earth". The thing did buzz, and the lamp flickered as well, and
eventually after a week or so, there was a reasonbly loud bang, and the
lamp stopped working.

How do I do this properly without the above problems?

Many thanks
Colin


He's talking bs.

fitting a lower power bulb might make more sense. Dimming kills energy
efficiency, and filament bulbs are already bad.


NT

In message .com,
writes
Hi,

we have a floor lamp that makes the room far too bright when on, and
leaves the room too dark when off.

alower wattage bulb?

--
Chris French

wrote:

Hi,

we have a floor lamp that makes the room far too bright when on, and
leaves the room too dark when off. So, we asked our unreliable
handyman to fit a dimmer switch, which he did, a normal click on/off
dimmer in a plastic housing, by cutting the main cord, and putting it
inbetween the plug and lamp.

He left the job muttering something about "it buzzes because there is
no earth". The thing did buzz, and the lamp flickered as well, and
eventually after a week or so, there was a reasonbly loud bang, and the
lamp stopped working.

How do I do this properly without the above problems?

Many thanks
Colin

Earth is irrelevant.

Apart frim safety.

He fitted a crap dimmer thats all.

SOME onterference may be larger without an eath, but the buzzing is just
a very crap dimmer.

On 31 Oct 2005 08:16:06 -0800, wrote:

we have a floor lamp that makes the room far too bright when on, and
leaves the room too dark when off. So, we asked our unreliable
handyman to fit a dimmer switch, which he did, a normal click on/off
dimmer in a plastic housing, by cutting the main cord, and putting it
inbetween the plug and lamp.

He left the job muttering something about "it buzzes because there is
no earth". The thing did buzz, and the lamp flickered as well, and
eventually after a week or so, there was a reasonbly loud bang, and the
lamp stopped working.

Does this lamp have a low voltage halogen bulb in it?

The buzzing noise, flickering and final bang symptoms suggest that the
lamp has (or had) a built in transformer or power supply unit that is
unsuitable for dimming.

How do I do this properly without the above problems?

If you have such a fitting then you would need to replace the power
supply unit with one that can be dimmed.

John
--
John White
SCA Electrical, Manchester http://www.scaelectrical.co.uk/
Domestic and commercial electrical contractors

Does this lamp have a low voltage halogen bulb in it?

The buzzing noise, flickering and final bang symptoms suggest that the
lamp has (or had) a built in transformer or power supply unit that is
unsuitable for dimming.

How do I do this properly without the above problems?

If you have such a fitting then you would need to replace the power
supply unit with one that can be dimmed.


Yes it is a halogen floor stander, with 10 flexible arms each with a
halogen bulb at the end of it.

So from what you are saying I will actually have to change the internal
workings/power supply of the lamp, in order to get it to work and its
nothing to do with earth or a crap dimmer switch?

In article .com,
wrote:
Yes it is a halogen floor stander, with 10 flexible arms each with a
halogen bulb at the end of it.

So from what you are saying I will actually have to change the internal
workings/power supply of the lamp, in order to get it to work and its
nothing to do with earth or a crap dimmer switch?

You need a dimmer stated to be suitable for 'low voltage lighting' use.

--
*Red meat is not bad for you. Fuzzy green meat is bad for you.

Dave Plowman London SW
To e-mail, change noise into sound.

wrote:

Does this lamp have a low voltage halogen bulb in it?

The buzzing noise, flickering and final bang symptoms suggest that the
lamp has (or had) a built in transformer or power supply unit that is
unsuitable for dimming.


How do I do this properly without the above problems?

If you have such a fitting then you would need to replace the power
supply unit with one that can be dimmed.



Yes it is a halogen floor stander, with 10 flexible arms each with a
halogen bulb at the end of it.

So from what you are saying I will actually have to change the internal
workings/power supply of the lamp, in order to get it to work and its
nothing to do with earth or a crap dimmer switch?

Is it a low voltage array?

On 1 Nov 2005 04:40:01 -0800, wrote:

Does this lamp have a low voltage halogen bulb in it?

The buzzing noise, flickering and final bang symptoms suggest that the
lamp has (or had) a built in transformer or power supply unit that is
unsuitable for dimming.

If you have such a fitting then you would need to replace the power
supply unit with one that can be dimmed.

Yes it is a halogen floor stander, with 10 flexible arms each with a
halogen bulb at the end of it.

So from what you are saying I will actually have to change the internal
workings/power supply of the lamp, in order to get it to work and its
nothing to do with earth or a crap dimmer switch?

That's right. A lot of these fittings have a power supply that objects
to the chopped or pulsed waveform that comes out of most dimmers.

In extreme cases the electronics in a switched mode power supply can
get very confused - and go bang.

There are replacement power supply units (often called transformers)
which are specifically designed to work with dimmers. You also need to
be certain that you get an appropriate unit for the total wattage of
the bulbs. Most units have a minimum wattage specified as well as a
maximum, so the old idea of getting a big one just in case does not
always apply.

Also, as other posters have said, the dimmers themselves normally have
to be rated at a higher wattage when used with halogen lights rather
than incandescent bulbs. This is because halogen lamps take a higher
current when first switched on. Typically 250 Watts of halogen lights
will need a 400W dimmer.

John
--
John White
SCA Electrical, Manchester http://www.scaelectrical.co.uk/
Domestic and commercial electrical contractors

Thanks for all the responses by the way -- very good of you.

So from this, we are saying that it won't have been the dimmer switch
that went bang, but the actual transformer in the lamp, meaning the
lamp is now knackered?

So whats my plan of action? There are ten bulbs, each labelled 12V10W,
so what transformer should I replace it with in order to

(a) allow the lights to work
(b) ensure we dont get any more load bangs
(c) be able to fit a dimmer switch

?

Cheers
Colin

Also below the actual bulbs on each arm, is a sticky label stating "G4
MAX 10W". Does this mean I can get other "G4" bulbs, that are less
than 10W that would be dimmer than the current 10W ones?

Yes,
A quick google (g4 bulbs) gave:

http://www.moltengold.com/cgi-bin/eB...test.bulbs.htm

12V/5W Halogen should be quite a lot dimmer.
Will be pricey if you need ten though!




wrote:
Also below the actual bulbs on each arm, is a sticky label stating "G4
MAX 10W". Does this mean I can get other "G4" bulbs, that are less
than 10W that would be dimmer than the current 10W ones?

On 1 Nov 2005 06:21:46 -0800, wrote:

Thanks for all the responses by the way -- very good of you.

No problem

So from this, we are saying that it won't have been the dimmer switch
that went bang, but the actual transformer in the lamp, meaning the
lamp is now knackered?

Well it could be either or both, it's a bit hard to be certain without
actually seeing them.

So whats my plan of action? There are ten bulbs, each labelled 12V10W,
so what transformer should I replace it with in order to

(a) allow the lights to work
(b) ensure we dont get any more load bangs
(c) be able to fit a dimmer switch

You need a replacement transformer:
- with an output of 12 V (either AC or DC)
- with a maximum load of at least 100 W (e.g. 120 W)
- with a minimum load of less than 100 W (e.g. 50 W)
- that is labeled as suitable for use with dimmers.

Such as: http://www.tlc-direct.co.uk/Products/LTYT105.html

You also need a dimmer switch that is labeled as suitable for use with
low voltage lights, and which has a rating of at least 100 W.

You may find it difficult to get an in-line dimmer that is suitable.

John
--
John White
SCA Electrical, Manchester http://www.scaelectrical.co.uk/
Domestic and commercial electrical contractors

On 1 Nov 2005 06:26:13 -0800, wrote:

Also below the actual bulbs on each arm, is a sticky label stating "G4
MAX 10W". Does this mean I can get other "G4" bulbs, that are less
than 10W that would be dimmer than the current 10W ones?

Like this? http://www.tlc-direct.co.uk/Products/LAM91.html

They may exist but I don't know of any G4 bulbs less than 10W..

John
--
John White
SCA Electrical, Manchester http://www.scaelectrical.co.uk/
Domestic and commercial electrical contractors

snip
Also, as other posters have said, the dimmers themselves normally have
to be rated at a higher wattage when used with halogen lights rather
than incandescent bulbs.

Sorry to be picky, but halogen bulbs *are* incandescent. "Ordinary"
light bulbs (i.e. with a filament in inert gas, but not halogen, etc)
are usually referred to GLS or General Lighting Service lamps.

This is because halogen lamps take a higher
current when first switched on. Typically 250 Watts of halogen lights
will need a 400W dimmer.

It is true that halogen lamps take a higher current when switched on,
but the use of a dimmer masks this inrush for low-wattage lamps. The
very act of placing a dimmer between the supply and the lamp creates a
soft-start effect which has the advantage of prolonging the life of the
lamp. The primary reason for de-rating the dimmer is to allow for
inrush/inefficiency in the transformer(s) not the lamps, per se.

HTH

Dave Plowman (News) wrote:

In article .com,
wrote:

Yes it is a halogen floor stander, with 10 flexible arms each with a
halogen bulb at the end of it.


So from what you are saying I will actually have to change the internal
workings/power supply of the lamp, in order to get it to work and its
nothing to do with earth or a crap dimmer switch?


You need a dimmer stated to be suitable for 'low voltage lighting' use.


And you need a LV transformer that is 'suitable for being dimmed'

Toroids can work..but electronic ones that are able to handel the
waveforms work too.

In article ,
The Natural Philosopher wrote:
Yes it is a halogen floor stander, with 10 flexible arms each with a
halogen bulb at the end of it.


So from what you are saying I will actually have to change the internal
workings/power supply of the lamp, in order to get it to work and its
nothing to do with earth or a crap dimmer switch?


You need a dimmer stated to be suitable for 'low voltage lighting' use.


And you need a LV transformer that is 'suitable for being dimmed'

Any transformer can be 'dimmed'. Some SMPS not - or at least by a usable
amount.

Toroids can work..but electronic ones that are able to handel the
waveforms work too.

Since the OP didn't complain about the dimmer not actually dimming the
lamp I assumed it has a PS that can be dimmed. ;-)

--
*It doesn't take a genius to spot a goat in a flock of sheep *

Dave Plowman London SW
To e-mail, change noise into sound.

On Wed, 02 Nov 2005 15:59:37 +0000 (GMT), "Dave Plowman (News)"
wrote:

Any transformer can be 'dimmed'.

That's a rather risky statement. The extra harmonics from the average
phase choppng dimmer are going to increase losses in an average
transformer core, leading to excess heating. It's "dimmable" but you
need to allow for potentially a large derating in output, hot running
and a loud buzzing noise.

In article ,
Andy Dingley wrote:
Any transformer can be 'dimmed'.

That's a rather risky statement. The extra harmonics from the average
phase choppng dimmer are going to increase losses in an average
transformer core, leading to excess heating. It's "dimmable" but you
need to allow for potentially a large derating in output, hot running
and a loud buzzing noise.

Indeed. Didn't say they were all ideal for this. And of course the design
of the dimmer can come into it too.

--
*TEAMWORK...means never having to take all the blame yourself *

Dave Plowman London SW
To e-mail, change noise into sound.

In my day a 'dimmer switch'was the length of cane the headmaster carried...
har har.

That could effect some amazing transformations..

Hi,

managed to take the dimmer out and reconnect the wires over the weekend
and the lamp still works so it was the dimmer that went bang and not
the transformer. It still resembles having the a small piece of the
sun in the corner of the room though, so as per another poster, I am
going to buy some 12V5W G4 bulbs (see link below) to replace the 12V10W
ones that are currently in it.

One last question? Will I be able to mix 12V10W and 12V5W bulbs?

Cheers, and thanks for all your help,

Colin

http://www.moltengold.com/cgi-bin/eB...test.bulbs.htm

John White wrote:
On 1 Nov 2005 06:26:13 -0800, wrote:

Also below the actual bulbs on each arm, is a sticky label stating "G4
MAX 10W". Does this mean I can get other "G4" bulbs, that are less
than 10W that would be dimmer than the current 10W ones?

Like this? http://www.tlc-direct.co.uk/Products/LAM91.html

They may exist but I don't know of any G4 bulbs less than 10W..

John
--
John White
SCA Electrical, Manchester http://www.scaelectrical.co.uk/
Domestic and commercial electrical contractors

Changed the bulbs for lower wattage ones and the jobs a good 'un --
wish I had thought of that in the beginning, would've saved a lot of
bother!

Thanks to all for your help.

:-)