Automated Fixtures Restriking a lot?

[photoatdv]

Okay-- I'm stumped on this one. I saw a show last night where they had some movers (pretty sure VL3500s) on the FOH truss, then some similar looking (but couldn't tell for sure) ones on the side booms. The ones on the side booms appeared to be doused and restruck pretty much every black out. Where I was I could see the spill from the lamp cap and vents... which was going away on black outs on those but not the FOH ones.

So-- any idea why/ how they'd be restriking a fixture that looks like a VL3500 probably upwards of 2 dozen times in a show?

 

[jxgriffi]

I'm 99% sure they would NOT be dousing the lamps like that.

If there were indeed VL's, they have a setting on them that once the douser is closed for a set number of seconds, the lamp drops to 1/2 power inside the ballast to keep from cooking the electronics.

As soon as the douser opens, it immediately bumps the voltage back up and the lamp is at full intensity.

If they were dousing and striking, it would take several minutes to get back up to a good color temperature each time (which I'm sure it didn't have).

J

 

[derekleffew]

If that's what was happening, it's a bad practice. 1) Rule-of-thumb says each lamp strike takes one hour off the lamp life. 2) Many fixtures will not allow a hot restrike, one must wait 5-10 minutes for the lamp to cool before it can be re-lit.

 

[photoatdv]

Is there some other way they could have been making the spill around the lamp cap and vents go away?

 

[Bobby]

Is there some other way they could have been making the spill around the lamp cap and vents go away?

The vents allow it to breath. I believe if you were to cover them up, the fixture would over heat.

 

[sk8rsdad]

It might be that something moving in or out of the optical path that would change how light is reflected out of the vents.

The more likely scenario is as jxgriffi describes and the lamp is going into reduced power mode and the amount of visible light coming out the vents is reduced accordingly.

 

[DCATTechie]

Could it have been a fixture with electronic dimming as opposed to mechanical dimming?

 

[rochem]

My guess is that they were something like a VL1000T, which uses a Tungsten source and actually dims the lamp as opposed to using a mechanical douser. How well could you see the fixtures? Are you confident they were VL3000-series, or could they have been VL1000s?

Photo courtesy of Vari-Lite

 

[jxgriffi]

BTW: The VL1000 also comes in an Arc version...and does not have the lamp reduction feature. I know VL2k's and 3k's all have the feature.

 

[bdkdesigns]

The VL1k Tungsten was my guess as well. Are you sure that you saw mechanical dousers on the unit at all or did it just appear to be dimming.