Axiom Home Page Forums General Discussion Technical Questions Do you use a UPS with your projector / HT system?

Hi all:

So I am hoping to pull the trigger on a projector / screen combo. I'm wondering about people's perspectives on an uninterruptible power supply - especially as it relates to a projector and having that extra battery back up to help prevent a sudden power outage that might stop cooling of the projetor lamp.

I'm curious how many of you use an uninterruptible power supply, and if so for what reason?

Thanks!

I've had a projector for about 5-6 yrs now, and just have it routed to my AV closet going through my Tripp Lite surge/conditioner.

I've had an Epson projector for about 4 yrs now that's just plugged into the wall. The power has gone out about four times while it was in use and I'm still on the same bulb (~3800 hrs, rated for 3000).

On the other hand, you can get a low power APC UPS for about C$60 (the cooling fan doesn't require much juice) vs $400 for possible bulb problems.

I don’t use a power conditioner or battery backup. I have a dedicated circuit to the projector and 3 dedicated circuits to the AV closet. We usually have pretty good power here so I didn’t think I needed anything extra. But as soon as I say this we’ll probably get an outage. Has anyone here experienced an unprotected power outage while their projectors were on? I’m curios as to how much that may affect bulb life.

That's exactly why I bought a UPS. They cost less than a bulb.

I have a UPS for my AV stuff, but I have no projector. It's mainly for the TiVo.

Same here...UPS on all the AV except the monoblocks.. especially for the DLP bulb and Tivo. We have enough dips in power here in South Florida to warrant it.

Id, there's no real benefit to be gained from a UPS for the situation that you describe. This has been discussed here and elsewhere in the past and it's been pointed out that if the power goes off and stops the fan, the bulb doesn't get hotter, since it shuts off too. Without the fan running it simply takes longer to cool down, but this isn't significant.

I have an APC SmartUPS 1000 behind my DLP and other gear to condition power, to prevent damage from outages and spikes. When windstorms tend to blow trees across one's power lines, that's a good thing.

On my DLP, the bulb fan stays on for 2 minutes after the TV is powered down. If the bulb has plenty of hours on it, and outages are frequent enough (while the TV's on), it would certainly hasten the bulb's demise. When I first got the TV, I was visiting one of my accounts, a TV repair business. I told the owner about my new acquisition, and one the first things he said was to be careful of letting the TV shut down as designed, because of calls for early bulb failures due to non-standard shut methods (power strips, etc).
So, warranted or not, a UPS gives me that 'peace of mind' factor... and I can keep watching Boston Legal uninterrupted!!

Not true John. When the bulb is lit, the fan is running to keep it cool. The fan is needed and whomever was in the discussion before that came to the conclusion you reference above was also wrong.

Mdrew is right. Its a sure fire way to not only shorten life of an expensive lamp, but possibly damage internal components in the projector from overheating. Spikes from power outages are another problem though thats solved with a surge suppressor.

Hi all:

Thanks for the great discussion. I suppose I could get a small UPS (which would have some surge protection) for the projector, and then a standard surge protector for the rest.

Alternatively I could just plug everything into a simple power strip and use the savings to buy better cables - that's bound to help enhance my A/V experience....

Yeah, I gotta agree with Mike and John here, John. If projector lamps didn't need to be actively cooled when turned off, projectors wouldn't run the fans for 5 minutes when powered down.


EDIT: Here's my totally made up hypothesis: while the projector is on, the bulb is clearly hot. The fan keeps the glass of the bulb cool, but obviously can't do anything (nor should it) to keep the filament (or whatever the actual light source is) cool. When the power cuts out, the fan stops, as does the light. However, the glass can heat up because the filament (or light producing element) will still be radiating heat. If the glass heats up too much, well then...

Then what? The suspense is killing me!

Thermal shock!

But, where's the earth-shattering 'Ka-Boom'?

That happens when pay for the new bulb.

I don't like your theory, Ken.

When the PJ is powered, the fan removes excess ambient heat from the bulb enclosure, but I doubt it actually lowers the temperature of the bulb glass directly. Sure, if the bulb were on without the fan, then the hot air build-up in the confined space would contribute to a hotter bulb and might actually melt the enclosure.

I think a point we can all agree on is that the less heat a bulb experiences, the longer it will last -- more heat means more entropy means more rapid decay of the filament.

JohnK, sure, when the power cuts out, the heat of the entire system will begin to diminish; however, because it's the total heat over time that determines the longevity of a bulb (absent other forces such as vibration shock), active cooling of a recently extinguished bulb will contribute cumulatively to its longevity.

Yeah, that makes sense too.

Yeah Peter, but the bulb is hotter when the projector is on(with the fan running of course)than it is during the few minutes of the extended cooling period with the fan off after an occasional power failure. So there's less additional heat involved than if the projector was simply operated normally for a few more minutes(i.e., if the power hadn't failed). The previous point still applies; there's no damage done to the bulb by a power failure and no need for a UPS in the situation.

I believe I see your point now. Since power failures are (hopefully) rare, the additional bulb life added by maintaining the ability to cool the bulb during those rare occasions is negligent. As a matter of fact, a power outage that shuts both fan and bulb off should actually extend the life of the bulb. Since the single greatest factor contributing the the bulb's demise is electrical current through the filament -- and that stops as soon as the power cuts out -- any situation where the bulb is better from a longevity standpoint than when the bulb is on.

I think you've convinced me.

As long as the power outage doesn't last less than an hour and the user doesn't turn the projector back on within that hour.

So who's going to inform the engineering staff of ALL projector manufactures and tell them about this startling revelation from the Axiom board members that a fan isn't needed for bulb cooling? I'm sure they would appreciated it, as it will make them less expensive to build and put more money into their R/D budgets for researching things like....if a fan should run after the bulb is off, or if the fan should run at a higher speed if the bulb is not in economy mode, or if the fan should run at a higher speed at higher elevation or not. Oh, never mind, they already figured that out!!

I'm thinking power failures could still be harmful, depending on your model and how cleanly the power turns back on. In my area, the power company is good at getting the power back on but it tends to come back on with a bang. We (our province) tend to blow up more appliances when the power comes back on than from oddball power surges, lightning or any other reason.

Now if the projector stays off after the power outage, probably a non issue. However, if the projector is designed to turn back on with the power, lamp and all, the lamp will take the full brunt of the hit.

This may not be as much of an issue for some people anbd I have no idea if even my projector's on/off functionality works this way after losing commercial power. It's still in the box but now that you have me thinking, I might take it out to do another test.

Mike,

I'm not arguing the merits of cooling a projector bulb or trying to say the engineers who designed the projectors are stupid. As I stated yesterday in my original response, heat acts cumulatively, so less is good over the long term.

My second post agrees with John in the sense that buying a UPS simply to enable the proper bulb cooling cycle is probably not going to significantly lengthen the bulb's life simply because a power outage is relatively rare.