Discharge lamp wattage - fixture compatibility

[KevinE]

some light fixtures I have at the moment they are meant for 70w lamps we currently have 150w ones in

 

I dont think any professional can advise doing this. If you're happy running your own fixtures with the wrong lamp in then on your own head be it! As a point of reference the BR has to maintain a certain standard!

 

I agree many higher wattage metal halide lamps will strike and run at the lower wattage, having seen many factories using MH high-bay fitiings with the wrong lamps in, but it's generally due to ignorance of the correct lamp to use and a little serendipity that they work at all.

[adam2]

some light fixtures I have at the moment they are meant for 70w lamps we currently have 150w ones in

 

I dont think any professional can advise doing this. If you're happy running your own fixtures with the wrong lamp in then on your own head be it! As a point of reference the BR has to maintain a certain standard!

 

I agree many higher wattage metal halide lamps will strike and run at the lower wattage, having seen many factories using MH high-bay fitiings with the wrong lamps in, but it's generally due to ignorance of the correct lamp to use and a little serendipity that they work at all.

 

 

Indeed, use of the wrong lamp in architectural/industrial/retail lighting is very common, and generly the lamps and ballasts survive OK.

That does not mean that its good idea or recomended though!

 

Under running most metal halide lamps produces a very pronounced green colour, almost useless for the intended purpose, though people still do it!

[csg]

The thing I find most supprising is that some here think that spending potentially a couple of hundred £ on a set of larger than required lamps is a better and more predictable solution than spending about £7 on a sheet of N.D. gel, a solution which by its nature must work

 

I know what solution makes more sense to me! - particularly if im meant to be in business....

[boatman]

For example some light fixtures I have at the moment they are meant for 70w lamps we currently have 150w ones in , the ballast runs at the same temp as when using 70w lamps. The only end result is the lower output. Joe

 

You get a lower output when you run 150W lamps intead of 70W? You must be doing something wrong.

[Joe Betts]

You get a lower output when you run 150W lamps intead of 70W? You must be doing something wrong.

 

If you read SSLS's earlier posts you will find this is due to the ballast limiting the current supplied to the bulb.

It's effectlively working like a dimmer.

 

To sum up some of the recent posts:

 

1) If you dim a halogen fixture, the CT changes. The same basic rule applies to limiting current supplied

to a discharge lamp. It will be dimmer, and have a different CT.

2) You will void manufacturers warranty by using an unrecomended bulb.

3) The bulb dimensions may differ - potential mis fit between feflector and lenses, potential arc length difference.

 

I think all in all the general concensus is most would not recomend doing this.

 

CSG makes a very valid point re ND gel - cheaper, more practical - less risk.

 

You can also get this in a perspex type form. This may be useful to fit to the back of the fixed lens on your fixture.

[junogoose]

how about just using a piece of neutral density ( N.D) gel infront of the lens - available in many different stops, this has to be a much more reliable and cheap way of droping the intensity where the fixture does not have a dimmer shutter

 

I should have mentioned that, for now, that's what I intend to do. My interest in switching to a lower CT 250 is to increase the red spectrum output while also reducing the perceived brightness.

 

For now, ND filters will do, since my priority is to (attempt) to balance my Q-Scan's(2) with ADJ X-moves(4) in a small club.