Power/lamp question

[jmsinick]

Hello,

I am wondering if I can take four 1k par cans and by setting a max patch value of 50% on the console that i will be able to two-fer all the lights to one circuit of 2.4k.

What my problem is that i use a four color cyc light wash but only have 3 cell cyc lights and so i want to buy the par can in the gap between my cyc lights. The lamps in my cyc lights are 500w and so if i cap the 1k pars at 50% they are in theory around 500w.

My color order right now is with all cyc lights
R A G | B R A | G B R | A G B | R A G...and so on

I want it to be with a cyc..par..cyc order
R A G | B | R A G | B | R A G | B...and so on

that way it will balance out the wash.

I have a ton of pars just floating around so to dedicate 18-20 lights for this is nothing.

Any thoughts?

Thanks,
Jeremy

 

[zac850]

No, you can not.

A dimmer runs not by giving less power to the light, but by turning on and off the light very quickly. Even if you only had the lights up to 50%, it would still be 4kw of power on the dimmers, something that they would not like very much.

Perhaps you can find some 500w lamps and put those into the PAR's?

 

[propmonkey]

just get 500w lamps for your pars.

if you run them at 50% youll be changing the color temp.

 

[zac850]

if you run them at 50% youll be changing the color temp.

Thats another good point. Just because i'm curious, does anyone know what the average lamp (for me, I'd like to know with the HPL) changes color temp as its dimmed?

But as you dim a light, your colors don't look as good, so thats also something to keep in mind.

 

[ricc0luke]

No, you can not.

A dimmer runs not by giving less power to the light, but by turning on and off the light very quickly. Even if you only had the lights up to 50%, it would still be 4kw of power on the dimmers, something that they would not like very much.

It depends on the type of dimmer they have. Not all dimmers work that way, just the majority of the newer ones do.

 

[zac850]

OK, this is very true, however, it is hard to find a theater that does not work like this. I know of one theater that uses a resistance dimmer to control the house lights (I know thats not the proper term, but the correct term escapes me)

 

[ship]

Thats another good point. Just because i'm curious, does anyone know what the average lamp (for me, I'd like to know with the HPL) changes color temp as its dimmed?

But as you dim a light, your colors don't look as good, so thats also something to keep in mind.

Remembering of course that if the HPL is 115v it will probably be different than the at full line voltage at the fixture powering that lamp. This factor starts at the point the 115v lamp is getting 115v of power not from the say 118v at full from the dimmer in accuracy.

A 5% change in the voltage applied to the lamp results in
-Halving or doubling the lamp life

(The effect of voltage on the light output of a lamp is ±1% voltage over the rated amount stamped on the lamp, gives 3.1/2% more light or Lumens output but decreases the life by 13% and vise a versa. Do not operate quartz Projection lamps at over 110% of their design voltage as rupture might occur. - GE Projection)

-a 15% change in luminous flux (see above)
-an 8% change in power
-a 3% change in current
-a 2% change in color temperature (0.4% change per 1% voltage.)


Osram Technology and Application Tungsten halogen Low Voltage Lamps Photo Optics, p

 

[Foxinabox10]

A 5% change in the voltage applied to the lamp results in
-Halving or doubling the lamp life

So, would operating at 110 volts or 120 volts double the lamp life according to what you're saying?

 

[Mayhem]

Well if I understand it correctly, running (in this example a 115V rated lamp) at 110V wil double the lamp life, where as running it at 120V will half the lamp life.

Some lights actually do have a lamp save switch on them which actually reduces the voltage as opposed to dimming, which switches the lamp on and off but at the same voltage.

 

[Foxinabox10]

And what are the drawbacks of setting all of your 115V lamps to run at 110V?

 

[ship]

And what are the drawbacks of setting all of your 115V lamps to run at 110V?

Given the above formula's, output and color temperature.

On the other hand, should you wish there is some normal Leko 100v lamps in 575w and 750w on the market and some 575w HPL lamps on the market also to make your "specials" at full intensity when using the 115v lamp for long life. Not in any of the types above very popular lamps thus their cost effectiveness might not be worth the lamp savings on other lamps.