Lamp Types

[mrg198]

Hi,

 

We've been tidying up our workshops recently and I've scraped together the various spare lamps we have accumulated into one storage place. I wanted to try and fathom which fixtures use each of the various lamp types. I can look up each of the fixtures but they are often quoted with several different codes of lamp being suitable and I'm not sure I really understand what the differences are.

 

For example I have lamps that include T18. T25, T26, T27 and M40, but from looking on the wiki and on google it seems that most fixtures will take M40/T18/T25 (500W) or T26/27 (650W). What I don't understand is what's the difference between them (other than W) and why would I chose to use say a M40 rather than a T18 or a T25? I also notice from the charts I've found

 

Lamp chart for example

 

that some fixtures that list T18/T25 don't list M40. Why would they be unsuitable or is it just that those manufacturers haven't mentioned them?

 

Somewhat frustratingly most of our fixtures have lamps (Philips I think) that only have a manufacturer's part number and not the lamp code stamped on them so you have to look it up to see which it is!

 

Any thoughts?

[musht]

why would I chose to use say a M40 rather than a T18 or a T25?

 

Usually lamplife , but traded for output and or colour temperature.

 

T class lamps, T for Theatre, have a, think, consistent 3200K colour temp and usually not great rated lamp life.

 

CP, as in CP60 etc, is Colour Photography

 

M series lamps, dunno what M is for, are display class lamps intended for shop windows and the like

and usually emphasis is on long life,with a lowering in colour temp.

[Neil Hampson]

As far as I remember, the difference between the T18 and T25 is the pattern of the filliment, one of them has the filiments staggered in the vertical plane, the other has all of the filliments in the same plane, the trade off is slightly improved focusing in a profile for a slightly reduced lamp-life. of the newer T class lamps there is generally two lamps available, most vendors will not distingush between the two, if you order a 650W lamp and recieve whichever lamp was in stock T18 or T25.

[Brian]

...M40....

The M40 is the long life (2000hr) version but with reduced (8500 vs 11,000 lumens) output.

[David A]

The M40 filament is lower than the theatre class lamps, so it doesn't sit in the middle of the reflector and gives an oval beam, in addition it seems to be more vulnerable to vibration so that the actual lamplife is often less than that stated.It used to be popular in ray lights.

[Brian]

The M40 filament is lower than the theatre class lamps,...

I thought that too and thought I had a pile of them pulled from units for that reason but all the references I can find shows the M40 with an lcl of 46.5, the same as T18s etc. Odd.

http://www.clearlight.com.au/PDF/HalogenLamps.pdf