Making the best of HID Lamp hours.

[FED]

Hi everyone.

I am currently automating a Turn ON and Turn OFF sequence for movers (DTS XR8 WASH + SPOT) using HID lamps (for easy operation by students). It is basically a set of auto-follow cues armed, disarmed and triggered by macros.

E.g.
Cue 1 - Park Power Supply
Cue 2 - Strike Lamp
Cue 3 - Position Home, Standby for first show cue.

Using macro variables, I can arm or disarm triggers that start or about running the cue list, with the intent of extending lamp life. (I can disarm a Turn ON lamp sequence if the lamp had just been turned off, for a set amount of time, after which the sequence is rearmed for triggering.)

Here's what already I know about HID lamps from books and the ML manuals:
- Every strike reduces lamp life by about 3 hours.
- Re-striking a lamp that has just been turned off before the salts recrystallize significantly reduces lamp life.

So what are some guidelines should I follow in regards to the striking of HID lamps with the intent of extending lamp life.

TL;DR - How long should I wait before I re-strike a HID lamp that had just been turned off.

Thanks!

 

[DELO72]

TL;DR - How long should I wait before I re-strike a HID lamp that had just been turned off.

Thanks!

It depends on a few things-
1) The type of lamp. Some lamps are not made to ever be Hot-restriked, and must be allowed to cool down at least 1.5 minutes before you attempt to re-ingnite them or you have high risk of flash-over and can fry the pins/socket. Lamps that meet this criteria are single-ended types with GY9.5 or GX9.5 bases, or other single-end bases without much seperation between the pins. HSR, MSR/SA, HSD, and HTI/SE are all examples of this kind of lamp.
Double-ended lamps never have risk of flash-over as their contacts are further away than the electrodes the electricity is trying to cross--however their hot-restrike capability is directly related to the power of the ignitor in the fixture. Which bring us to #2....

2)Some fixtures are specifically built to support hot-restrike and have more powerful ignitors. Some are not designed to support that feature or intended for that use. CONSULT THE MANUAL/ or Product Rep! For a non-hot-restrike fixture, typically the first 90 seconds are the hardest to get the lamp to ignite, so wait 1.5 minutes or more to strike it. For fixtures (and lamps) that ARE designed to support hot-restrike capability, you should wait 15 seconds after turning off the fixture before attempting to restrike it.


Some items to note: You should always allow a lamp to reach steady state once you ignite it before attempting to switch it off. Failure to do so will prematurely age the lamp and can also cause the earth salts and mercury to condense on the inside of the quartz, making it harder to ignite the lamp during future lamp strikes.
This action causes the mercury (still in a liquid/solid form) to splatter over the inside of the envelope as it has not had time to reach gasseous/plasma state. The lamp will now have a black shiney look to it. You now have a pretty paper weight as the lamp will no longer ignite.

Also- clean the fans regularly! The temperature inside the fixture must be maintained properly or the lamps will overheat, prematurely age, and or fail. Fog/Haze particles + dust = clogged fans.

Hope this helps.

 

[JD]

- Every strike reduces lamp life by about 3 hours.

Ehh... More like an hour. Years and years of shows with the old Satellite I 's which used an HMI 575 lamp. Shows were 45 minutes, 30 minute breaks, 4 in a row each night. We always shut down on the breaks. (bad to leave a lamp lit in a club full of drunks!) Lamps were rated at 400 hours. Never had one fail under 1500 hours. (They did start to get dim!) When I sold out, each of the spots had about 14,000 hours on them. With the exception of one that broke in transit, all were replaced when our tolerance of the light level got annoying. Had a couple that took a few hits of the ignite button to get going, and at least one that started dropping during the show. The Satellite had a 35kv ignitor, can't remember not getting a hot re-strike if the power dipped. (Not like the present movers with the anemic auto-ignitor system.)

More important is to make sure the lamp comes up to full temperature before shutting down. Not doing that will really kill off the lamp. Once off, they should remain off for at least 15 minutes if it is a planned shut-down. In other words, the most important thing is to run them through their full warm-up AND cool down cycles if possible. If you're doing a hour show with a 15 minute intermission, let em' run. If you have an hour break between shows, turn them off.

 

[Les]

The line between when to douse vs shut down has been [-]debated[/-] discussed here a few times before.

http://www.controlbooth.com/forums/lighting-electrics/26545-douse-not-douse-question.html
http://www.controlbooth.com/forums/lighting-electrics/10119-moving-light-lamp-cool-down.html
http://www.controlbooth.com/forums/lighting-electrics/22377-lycian-spotlight-cool-down-time.html
http://www.controlbooth.com/forums/lighting-electrics/7785-strong-super-trouper.html