Lamp anomaly

[Phil Allison]

Hi,

I tested a 75W Osram clear lamp & a 70W No Frills halogen (claims
100W equivalent) - the Osram measured 54ohms and the halogen 56ohms.

On 240V, the Osram drew 325mA and the halogen 302mA.

The resistance rises are 13.7 times and 14.2 times = essentially the same
filament temps.

However, the filament in the Osram is longer by about 40% plus the wire is
also slightly thicker.

Now, light output is proportional to surface area for equal temps, so the
Osram
MUST deliver more light.

Putting each lamp inside a white, 15cm spherical ceiling fitting and using a
DSE lux meter - I found the Osram put out fairly even light in all
directions
while the halogen is uneven and quite poor in the downward direction.

Dunno which is brighter overall - SFA in it really.

Except one is banned and the other is legal ......



.... Phil

 

[Clifford Heath]

On 02/10/13 14:06, Phil Allison wrote:

I tested a 75W Osram clear lamp& a 70W No Frills halogen (claims
100W equivalent) - the Osram measured 54ohms and the halogen 56ohms.
On 240V, the Osram drew 325mA and the halogen 302mA.
The resistance rises are 13.7 times and 14.2 times = essentially the same
filament temps.

Pretty interesting, Phil. Is it possible that different filament composition
could mean that the filaments are not actually at similar temps though?

However, the filament in the Osram is longer by about 40% plus the wire is
also slightly thicker.

They're double coils aren't they (a coiled coil)? Can you actually see this?
My eyes aren't good enough to pick it, but with enough magnification it's
visible.

Now, light output is proportional to surface area for equal temps, so the
Osram MUST deliver more light.

Is all the emission from the metal surface, or does some come from a partial
plasma around the surface? Because the extent of that plasma would change
the effective surface area.

Putting each lamp inside a white, 15cm spherical ceiling fitting and using a
DSE lux meter - I found the Osram put out fairly even light in all
directions
while the halogen is uneven and quite poor in the downward direction.

Hmm, right where you're most likely to want light. That's pretty crap.

Clifford Heath.

 

[Trevor Wilson]

On 2/10/2013 2:06 PM, Phil Allison wrote:

Hi,

I tested a 75W Osram clear lamp & a 70W No Frills halogen (claims
100W equivalent) - the Osram measured 54ohms and the halogen 56ohms.

On 240V, the Osram drew 325mA and the halogen 302mA.

The resistance rises are 13.7 times and 14.2 times = essentially the same
filament temps.

However, the filament in the Osram is longer by about 40% plus the wire is
also slightly thicker.

Now, light output is proportional to surface area for equal temps, so the
Osram
MUST deliver more light.

Putting each lamp inside a white, 15cm spherical ceiling fitting and using a
DSE lux meter - I found the Osram put out fairly even light in all
directions
while the halogen is uneven and quite poor in the downward direction.

Dunno which is brighter overall - SFA in it really.

Except one is banned and the other is legal ......



... Phil

**Another good reason why I always avoid dodgy lamps and stick to decent
manufacturers. The worst I've seen are those Mirabella crap.

On a related matter, I recently purchased an Ecogem S9041 WW (Warm
White) 11 Watt LED downlight. Not only does it deliver respectable light
output (680 Lumen), but the spread of light is similarly impressive (it
is fitted with a nice diffuser). It is supplied with an electronic
'transformer' that is suitable for use with dimmers.

Anyway, a friend is fitting her new home with LED downlights and I
suggested she examine the Ecogem. Naturally, she reacted with horror at
the price $46.00 wholesale) and elected to use some $20.00 ones she
found. Sadly, she finds that she needs more than twice as many to do the
same job as the Ecogems. More holes, more electricians' time.........
Reliability is unknown.

A fool and her money............

--
Trevor Wilson www.rageaudio.com.au

 

[Phil Allison]

"Clifford Heath"
Phil Allison wrote:

I tested a 75W Osram clear lamp& a 70W No Frills halogen (claims
100W equivalent) - the Osram measured 54ohms and the halogen 56ohms.
On 240V, the Osram drew 325mA and the halogen 302mA.
The resistance rises are 13.7 times and 14.2 times = essentially the
same
filament temps.

Pretty interesting, Phil. Is it possible that different filament
composition
could mean that the filaments are not actually at similar temps though?

** The colour of the two lamps looks very close, the halogen is a tad
whiter.

However, the filament in the Osram is longer by about 40% plus the wire
is
also slightly thicker.

They're double coils aren't they (a coiled coil)?

** Nope - simple coils that look identical.

Now, light output is proportional to surface area for equal temps, so the
Osram MUST deliver more light.

Is all the emission from the metal surface, or does some come from a
partial
plasma around the surface?

** The gas ( ie nitrogen or iodine) would be convecting rapidly near the
filament and AFAIK does not ionise.

A longer coil at the same temp must deliver more light.


..... Phil

 

[felix_unger]

On 11-February-2013 10:16 AM, Trevor Wilson wrote:

On 2/10/2013 2:06 PM, Phil Allison wrote:
Hi,

I tested a 75W Osram clear lamp & a 70W No Frills halogen (claims
100W equivalent) - the Osram measured 54ohms and the halogen 56ohms.

On 240V, the Osram drew 325mA and the halogen 302mA.

The resistance rises are 13.7 times and 14.2 times = essentially the
same
filament temps.

However, the filament in the Osram is longer by about 40% plus the
wire is
also slightly thicker.

Now, light output is proportional to surface area for equal temps, so
the
Osram
MUST deliver more light.

Putting each lamp inside a white, 15cm spherical ceiling fitting and
using a
DSE lux meter - I found the Osram put out fairly even light in all
directions
while the halogen is uneven and quite poor in the downward direction.

Dunno which is brighter overall - SFA in it really.

Except one is banned and the other is legal ......



... Phil




**Another good reason why I always avoid dodgy lamps and stick to
decent manufacturers. The worst I've seen are those Mirabella crap.

I've had those incandescents literally explode off the ceiling and
shatter on the floor!

On a related matter, I recently purchased an Ecogem S9041 WW (Warm
White) 11 Watt LED downlight. Not only does it deliver respectable
light output (680 Lumen), but the spread of light is similarly
impressive (it is fitted with a nice diffuser). It is supplied with an
electronic 'transformer' that is suitable for use with dimmers.

Anyway, a friend is fitting her new home with LED downlights and I
suggested she examine the Ecogem. Naturally, she reacted with horror
at the price $46.00 wholesale) and elected to use some $20.00 ones she
found. Sadly, she finds that she needs more than twice as many to do
the same job as the Ecogems. More holes, more electricians'
time......... Reliability is unknown.

A fool and her money............

--
rgds,

Pete
-------
"If Julia is the answer, then what was the stupid question!"

“This election is about trust. The choice before the Australian people could not be clearer. It’s more tax or less. It’s more regulation or less. It’s less competence or more. It’s less freedom or more” - Tony Abbott, Federal Opposition Leader

Sept 14th. is National Rubbish Collection day.. ausnet.info/pics/rubbish_collection.jpg

http://www.facebook.com/SupportTonyAbbott

 

[Phil Allison]

"felix_unger"

**Another good reason why I always avoid dodgy lamps and stick to decent
manufacturers. The worst I've seen are those Mirabella crap.

I've had those incandescents literally explode off the ceiling and shatter
on the floor!

** Errr - like this:

http://sound.westhost.com/articles/il-cfl-6.htm

See half way down the page.

BTW:

The other two CFLs were ready to go the exact same way.

Woolworths " ESSENTIALS " brand 20 watt and 22 watt.




..... Phil