MSR 1200 Lamp

[saturnx21]

Hi all!

 

Does anyone know if the MSR 1200 Lamp gets hotter than the MSR 1200 SA (short arc) Lamp? :huh:

 

[Tomo]

Why do you want to know?

 

Discharge lamp fixtures are designed for one or more SPECIFIC lamps - you should never use anything other than the manufacturer's recommended lamps in a discharge fixture.

 

So unless you're designing a discharge fixture, this is something you do not need to know.

 

If you are, then you'll need to talk to the lamp manufacturer!

[saturnx21]

I need to know as I have converted a pair of TAS KP 12 moving heads to standard MSR (1200 watt) lamps instead of the SA version, I am aware that this may not be the best thing to do but having discussed the modification with a colleague* we came to the conclusion that the electrics prior to the lamp are identical although the optics may not be at there optimum for the standard MSR lamp it will course no ill effects to either the fixture or the lamps.

 

The only concern I have is that the standard MSR lamp has a longer arc than the SA version so it seems logical that it may get hotter than the short arc version but I am unsure, if indeed it does get hotter then the fixtures cooling system may not be up to the job of keeping it at an acceptable temperature.

 

*"the colleague" (who shall remain nameless!!!) has over 20 years experience in the trade and is the top tecie for two very well known lighting manufactures in the UK, so I feel that his opinion on this modification is a valued one! and as a result its quite safe for me to have made the change. I only point this out as I don't want anyone thinking that we are just young and naive people who have no idea about the complexity of such lighting effects!

 

If any of this post sounds in anyway patronising then I apologise as it is not intentional! but I am struggling to word my post any better!!! (probably should have paid more attention at school!!!)

 

:huh:

[blackbird]

Not a lampie, so may be obvious to others, but why would you want to change lamp types? Is it a cost thing?!

[saturnx21]

blackbird Posted Today, 7:56 PM

Not a lampie, so may be obvious to others, but why would you want to change lamp types? Is it a cost thing?!

 

Indeed it is! I have MSR lamps on stock but not the SA version! And I need the fixtures working over the next couple of weeks and I don't think it will be possible to get the SA versions over the next few days! :(

 

And to boot I feel its daft paying over 100 quid per lamp when I really wont be using them that much!

 

[Ynot]

Personally, I reckon you'd be best to discuss the potential regrade with the fixture manufacturers. All due respect to your nameless mate, but lantern design isn't usually something that's thrown together on the back of a fag packet. there will usually be reasons for spec'ing the bubbles involved - if you're looking to change them, then it may affect several aspects of the instrument.

 

And, of course, if the lantern is relatively new, you'll be invalidating whatever warranty may be left on it, and certainly any future technical support from the manufacturer, regardless of warranty.

 

TD

[Meduza]

With the same effect (1200W) I dont think that the length of the arc makes so big difference in heat, tough with a longer arc the point of light that needs to be focused will be bigger, and therefore the optics will not work as good as it did with the other lamp...

[saturnx21]

Normally I would even consider altering a fixture as I'm sure the manufacturer knows far more about lighting units than I could ever dream of knowing! But these fixtures are now at least 8 years old and as far as I'm aware Tas are no longer a going concern but I could well be wrong!

 

:(

[Ynot]

Fair enough (re Tas) but still I'd personally be very wary of making changes to something as basic as the bubble type unless it was a manufacturer's recommended upgrade.

Upping an old Patt 23 from a tungsten to the halogen conversion is one thing, but changing a discharge lamp could have further reaching issues.

 

I appreciate why you're considering it, but would advise caution.

[saturnx21]

Hi all

 

Just as a quick update I have converted the to fixtures I have and have had one of them running for a little over 2 hours so far and all seems well (I have been next to the unit at all times keeping a very close eye on it!)

 

Unfortunatly the other unit I have has a fan that has died but that will have to be in a new thread I suppose! :(

 

[David A]

As both lamps produce exactly the same amount of heat you cannot have a cooling problem.If your application is not critical the slight loss in optical efficiency is probably worth the money you will save.

[saturnx21]

Now that is music to my ears!!! :(

 

[Tomo]

As both lamps produce exactly the same amount of heat you cannot have a cooling problem.

This is not strictly true!

Both lamps dissipate the same amount of power (actually the HR uses slightly less) - but the power does not necessarily go to the same places, and the lamps may not cope with the same temperatures.

 

If you go to the Philips Broadway site (or whichever brand you're using), then you should be able to find various datasheets for the specific lamps in question.

I can't give you a direct link because there are differences between brands and subsets (single/double ended/HR/cold strike) - discharge lamps are funny things!

 

I'm rather surprised it struck at all to be honest - assuming Philips Broadway, the MSR 1200 SA needs between 2 and 5 kV, while the MSR 1200 HR needs between 45 and 55 kV.

I don't know whether to be impressed or worried...

 

One thing worries me though - the maximum permissible temperature of the SA lamp is 500°C at the pinch, 1000°C lamp, while the HR is only 350 and 700 respectively.

Assuming equal power dissipation, it's likely that the HR version would be running much hotter than designed.

 

Under those circumstances I'd expect premature lamp failures and more regular ruptures.

 

Take care!