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Sound Reinforcement - Forums for Live Sound Professionals - Your Displayed Name Must Be Your Real Full Name To Post In The Live Sound Forums => Lighting Forum => Topic started by: John Hyun on May 06, 2013, 02:40:23 pm

Title: par bulbs blowing out too early
Post by: John Hyun on May 06, 2013, 02:40:23 pm
my friend's church is having some lighting issues.  they have par64 and par56 fixtures for their stage light connected to dimmer and console.  some of the lights were blowing out a couple of months after replacing. I am wondering what the issue might be and where to start looking.

thanks!
Title: Re: par bulbs blowing out too early
Post by: TJ (Tom) Cornish on May 06, 2013, 02:46:00 pm
my friend's church is having some lighting issues.  they have par64 and par56 fixtures for their stage light connected to dimmer and console.  some of the lights were blowing out a couple of months after replacing. I am wondering what the issue might be and where to start looking.

thanks!
Look to bulb quality and rated lifetime.  This is one case where buying brand name is worth it - Osram/Philips vs. off-brands makes a difference.  Also, there are likely different bulb lifetimes to choose from.  For a permanent install, long-life bulbs are your best bet, though they'll be a little dimmer and yellower than short life bulbs.

About the only thing else to look at is if your building is over voltage. 115v bulbs are designed assuming a 120v supply and 5 volts of loss through the dimmer circuitry and wiring.  If you're starting at higher than that or if you have a particularly efficient dimmer, you may be getting more voltage at the socket than the bulb's nominal life is rated for.  The solution is to get 120v bulbs, 130v bulbs, or leave your master dimmer at 95%.
Title: Re: par bulbs blowing out too early
Post by: duane massey on May 06, 2013, 06:06:44 pm
Are you using par lamps or the "raylight" kits with DYS lamps?
Title: Re: par bulbs blowing out too early
Post by: John Hyun on May 06, 2013, 06:09:57 pm
Are you using par lamps or the "raylight" kits with DYS lamps?

par lamps
Title: Re: par bulbs blowing out too early
Post by: John Hyun on May 06, 2013, 06:16:34 pm
Look to bulb quality and rated lifetime.  This is one case where buying brand name is worth it - Osram/Philips vs. off-brands makes a difference.  Also, there are likely different bulb lifetimes to choose from.  For a permanent install, long-life bulbs are your best bet, though they'll be a little dimmer and yellower than short life bulbs.

About the only thing else to look at is if your building is over voltage. 115v bulbs are designed assuming a 120v supply and 5 volts of loss through the dimmer circuitry and wiring.  If you're starting at higher than that or if you have a particularly efficient dimmer, you may be getting more voltage at the socket than the bulb's nominal life is rated for.  The solution is to get 120v bulbs, 130v bulbs, or leave your master dimmer at 95%.

thanks tom.

long life bulb...2000 hours?
Their par56 bulb says 300w/120v
Their par64 bulb has nothing on it.

Is there a way of knowing if it was either a 500w or 1000w? the watts determine the overall brightness of the fixture, right?

Title: Re: par bulbs blowing out too early
Post by: Milt Hathaway on May 06, 2013, 06:28:14 pm

Is there a way of knowing if it was either a 500w or 1000w? the watts determine the overall brightness of the fixture, right?

Look into the lamp through the front lens. If you see a bare filament, then it is 500W incandescent. If the filament appears to be inside smaller long thin 'bulb', then it is a 1000W quartz.
Title: Re: par bulbs blowing out too early
Post by: James Feenstra on May 07, 2013, 12:54:14 pm
long life bulb...2000 hours?
most par lamps are rated for about 1/6th of that

If you're getting 1000+ hours out of any par lamp, you're doing pretty good

At the venue I used to work for I was changing lamps every 3-4 months when we were running 4+ nights a week.
Title: Re: par bulbs blowing out too early
Post by: John Hyun on May 07, 2013, 09:19:53 pm
most par lamps are rated for about 1/6th of that

If you're getting 1000+ hours out of any par lamp, you're doing pretty good

At the venue I used to work for I was changing lamps every 3-4 months when we were running 4+ nights a week.

i will give these a try
http://www.bhphotovideo.com/c/product/835502-REG/Sylvania_14932_500PAR64_MFL_Lamp_500W_120V.html

on paper it states 2000hours...real world application will be definitely less than that...
Title: Re: par bulbs blowing out too early
Post by: Mac Kerr on May 07, 2013, 09:37:49 pm
i will give these a try
http://www.bhphotovideo.com/c/product/835502-REG/Sylvania_14932_500PAR64_MFL_Lamp_500W_120V.html

on paper it states 2000hours...real world application will be definitely less than that...

Running lights 10% below rated voltage raises the life something like 10x. Check your building voltage to make sure you aren't a little over voltage, which will lower the life a lot.

Mac
Title: Re: par bulbs blowing out too early
Post by: Josh Daws on May 07, 2013, 11:46:38 pm
i will give these a try
http://www.bhphotovideo.com/c/product/835502-REG/Sylvania_14932_500PAR64_MFL_Lamp_500W_120V.html

on paper it states 2000hours...real world application will be definitely less than that...

don't try those...from looking at the ceramic on the picture they seem like the aluPAR series from osram...you want the other one. i can't remember the specific order code..and osram hasn't listed it on their site. if i remember tomorrow to get the order code i will. but definitely make sure that it is a glass Par59 and not the aluPAR...the lamp life on those are not that great at all.
Title: Re: par bulbs blowing out too early
Post by: Robert Weston on May 08, 2013, 08:19:12 am
Running lights 10% below rated voltage raises the life something like 10x. Check your building voltage to make sure you aren't a little over voltage, which will lower the life a lot.

Mac

+1

We lost several lights due to this.
Title: Re: par bulbs blowing out too early
Post by: Jeff Baumgartner on May 08, 2013, 02:33:36 pm
Are you sure the bulbs are burning out and it's not the sockets?
Check the prongs on the lamp.
Are they still shiny or black/brown and burned/pitted?

I was working with a local High School and every time I would sell them a new batch of lamps, I would get a call saying they didn't last very long.
Sent them a new order and same thing.
After a site visit, every socket was burned up causing premature lamp failure.
Title: Re: par bulbs blowing out too early
Post by: sam saponaro on May 29, 2013, 04:47:41 pm
Well just a longterm practiced theory as a band guy in an area with brutal winters. But I've allways allowed my stuff to acclimate to the temp when bringing them from the cold truck. And let them cool befor tearing down.
Does the church leave the heat off all day then just up and power the lights up?? Just a thought.