My bulb (approx 1000 hours) went out 2 weeks ago and currently, I have my PJ plugged in the wall outlet directly. I was wondering if it was due to a 'bad' power or something. Could I have avoided that by using a power conditioner or a UPS, etc?

What are you guys using as far as power is concerned?

Thanks
Frag

My bulb (approx 1000 hours) went out 2 weeks ago and currently, I have my PJ plugged in the wall outlet directly. I was wondering if it was due to a 'bad' power or something. Could I have avoided that by using a power conditioner or a UPS, etc?

Well, do you have a lot of power failures or bown-outs? Otherwise, I'd consider that unlikely. The lamp is not connected directly to mains power anyway but is regulated by dedicated electronics / power conditioning circuits. That should provide some filterting against, for example, spikes, and eliminate the effect of over/undervoltage. The two main reasons for a lamp to fail are degradition of the electrodes (leading to long-term failure, for example because the arc won't strike anymore) and manufacturing problems such as impurities in the bulb (leading to short-term failure). I can't quite see how an UPS would help with these issues.

... I can't quite see how an UPS would help with these issues.

Maybe not directly but in the last year or so we've had brownouts and power failures while the PJ was up and running. The UPS and power conditioner we have gives me peace-of-mind and, I think, probably does prevent damage especially when the power kicks back on. And, at $400+ for a lamp, I'm always happy to see the UPS doing its thing and keeping the power going to the PJ.

Btokars, which ups do you use?

Btokars, which ups do you use?

This one, from TigerDirect:
http://www.tigerdirect.com/applications/SearchTools/item-details.asp?EdpNo=770423&Sku=ULT31502

A power failure while the projector is in operation impacts the electronics as well as the lamp. Once power fails, the temperature of the internal components could rise to very high levels as there is no cooling to absorb the heat dissipated from the lamp assembly. Repetition of this will inevitably shorten the life of the electronics as well as the lamp.

Good to know,,,

I'll get a 350kva from OfficeDepot, this will help just in case I trip the circuit breakers w/ my 4 amps.

Regards,
Jose

Good to know,,,

I'll get a 350kva from OfficeDepot, this will help just in case I trip the circuit breakers w/ my 4 amps.

Regards,
JoseYou need a UPS that is rated 2 to 3 times the total watts usage by your PJ in order to make sure the load does not just shut off the UPS when the power fails. If your PJ wattage totals 325, you will need a 975 watt UPS. The VA rating is sometimes much higher thant the watts so look for the watts it can provide.

got an epson 1080ub, I think the specs say 170w so I need a ups between 350 - 500 kva ?

got an epson 1080ub, I think the specs say 170w so I need a ups between 350 - 500 kva ?

I am not an expert, but people on this forum that I trust told me to get a UPS that put out a true sine wave. I bought this one--a bit overkil, but...

http://www.provantage.com/apc-sua1000~7AMPU032.htm

got an epson 1080ub, I think the specs say 170w so I need a ups between 350 - 500 kva ?

Watts, not VA. For most UPSes the watts are only 60% of the VA rating.

The lamp is 170w so I would guess the entire PJ would be about 225 watts total. You will need a 750 to 1,000VA UPS.

I put a UPS on everything I can. Sine wave or not, at least it's consistent. The power supply can deal with the square wave. UPS does a great deal when it comes to consistent voltage. It's a a piece of mind, and they are pretty cheap, considering.

I wouldn't PJ without it...

A power failure while the projector is in operation impacts the electronics as well as the lamp. Once power fails, the temperature of the internal components could rise to very high levels as there is no cooling to absorb the heat dissipated from the lamp assembly. Repetition of this will inevitably shorten the life of the electronics as well as the lamp.

I second that. If there is a blackout and you don't have an UPS, the fan won't be able to cool down everything inside of your delicate PJ.

> If there is a blackout and you don't have an UPS, the fan won't be able to cool down everything

I don't think that is a problem with modern and well-cooled projectors (unless it happens on a very regular basis). The fan won't cool down the projector but neither does it "cool down everything" during a normal shut-down. In my Epson PJ, the regular cool-down is done and over with in 30 seconds. How much heat is transported ouf of the projector in that time? Imagine directing the normal exhaust airflow at your hand for 30s: that's the amount of fan relief we are talking abount. Not a lot of heat really. If that tiny bit of cooling is skipped on a few occasions, how much damage could it possibly do? The amount of additional heat injected into the system after the power-cut is zero Watt. All parts are at the intended temperature when the black out occurs.

> If there is a blackout and you don't have an UPS, the fan won't be able to cool down everything

I don't think that is a problem with modern and well-cooled projectors (unless it happens on a very regular basis). The fan won't cool down the projector but neither does it "cool down everything" during a normal shut-down. In my Epson PJ, the regular cool-down is done and over with in 30 seconds.

In my Optoma, cool down is 10 seconds. I agree that no fan probably won't matter, on occasion.

The real problem is not a total blackout. My opinion is the biggest problem is the glitching/flickering kind of power sags and surges. We get flickering sags when big storms come through and the power drops but comes back up almost immediately. It drops enough to cause some things to blink off and then other things power back up but with errors. Glitching a PJ could be bad for the lamp. That's why I use a ups. Many people don't and do fine but I'd rather reduce risks to an acceptable level.

hmm. Good info in here.

As a projector owner for the last 4 years in India where the power is an absolute disaster, I've used 6 projectors, 7-8 different UPSs and some inverters and generators so I have some experience with this question. I've had 350va UPSs that effectively did nothing other than produce noise as they failed to provide any backup.

I've understood the power factor on VA -> watts is around 70%. I don't think you need 3x the VA, but more like 1.5 to be safe. I think most PJs are like 200-250 watts so a 500VA and larger UPS should be more than enough.

My feeling is that a hard power shut off is fine for projectors. The post-power down fan is more to cool the lamp rapidly so you could switch it back on quicker if you needed (sort of a remnant of when projectors were designed primarily for business travelers).

I've never had a lamp blow on me, but I've almost always had a UPS running. I think abrupt power cuts are not a big deal (hassle aside) but voltage fluctuation can not be good and if you have them, then a UPS would be a very sound investment.

> biggest problem is the glitching/flickering kind of power sags and surge

Luckily, we don't have that on a noticable level. Does this kind of flickering extend to the lamp? The lamp's voltage is generated and regulated by the projector to keep the arc burning. I believe somewhere around 65V, with the exact voltage dictated by the lamp and its age. It's probably some kind of PWM-style regulation/supply, ie. mains voltgage is hacked into little pieces. Wave form (sinus or not), spikes and over/under-voltage shouldn't really matter as long as enough energy is stored in elements that store energy (predominantly capacitors and chokes).

> biggest problem is the glitching/flickering kind of power sags and surge

Luckily, we don't have that on a noticable level. Does this kind of flickering extend to the lamp? The lamp's voltage is generated and regulated by the projector to keep the arc burning. I believe somewhere around 65V, with the exact voltage dictated by the lamp and its age. It's probably some kind of PWM-style regulation/supply, ie. mains voltgage is hacked into little pieces. Wave form (sinus or not), spikes and over/under-voltage shouldn't really matter as long as enough energy is stored in elements that store energy (predominantly capacitors and chokes).I'm talking about 1 to 3 second flickers - that why I call them glitches. It doesn't go down hard, just enough to blink all the appliances and set the clocks to flashing.

I'm talking about 1 to 3 second flickers - that why I call them glitches. It doesn't go down hard, just enough to blink all the appliances and set the clocks to flashing.

If you get a lot of these, it may be useful to use a UPS, but I would be much more concerned about just having good surge suppression on all connections to the system including signal lines, and being certain that the systems are grounded properly.

All modern sets use thermal protection that will not allow the set to restart a hot lamp. Power supplies use a SMPS design that is typically very robust with respect to sagging power, and will have no problem with short term drops. When it drops too low the set will simply shut down.

The lamp issue that is most of concern is frequent restarts. Cooling is just not a big issue.

All modern sets use thermal protection that will not allow the set to restart a hot lamp. Power supplies use a SMPS design that is typically very robust with respect to sagging power, and will have no problem with short term drops. When it drops too low the set will simply shut down.That's fine when the electrical supply allows everything to work the way it is supposed to work - I have seen way too many times when things that aren't supposed to happen do anyway. When you jerk the eletrical supply around, cheap assembly line electronics don't always work the way they are supposed to.

Like I said, I do it for my own reasons - you do what makes you feel comfortable. Besides, when the power stays off for a few minutes, it's nice to keep on watching.

> 1 to 3 second flickers [...] just enough to blink all the appliances and set the clocks to flashing

That sounds like a voltage drop caused by a power-hungry device that was turned on somewhere (fridge, air conditioning, coffee machine etc.). Such effects can be quite visible if the cabling in or to the house is inadequate. I guess it could be a problem on the supply side, too, in some countries.

Long, slow and moderate voltage drops should not affect a PJ's lamp very much because, unlike regular lamps, the PJ's lamp is not connected to mains voltage but runs at a lower, regulated, projecor-generated voltage. So I wouldn't expect harm from long periods of under-voltage (long meaning more than a few ms). The PJ's current regulation circuit should be able to deal with it very well.

On short and high spikes: Short voltage spikes can be very high ideed (several times the nominal voltage). All delicate digital equipment has protection for that, for example in form of varistors. Additionally, any electronic device that contains a PWM (pulse width modulation) needs to have a filter (choke + capacitors) for spikes, for EMV reasons. Not so much to protect it against spikes from the outside but to protect the outside from the spikes of the PWM. Luckily, such protection works both ways. Therefore, the lamp should be protected from spikes. At least that's my theory.

Well, that is sort of correct, but makes a couple of faulty assummptions. First, most displays do not have much in the way of protection for large voltage spikes. Most do not have varistors for this purpose. The also don't have this kind of protection from the ground side, which is where many surges come from, over signal lines. What they do have in many cases are zener diodes for some protection on siganl lines, but these are to reduce catastrophic damage and usuall fail themselves with significant current. Most lamps are rather well isolated from line surges, but you can have some increase in voltage across a lamp in a large surge. It is likely something else in the PS will take damage before the lamp will, however. The filtering on the a.c. input on switching power supplies is not really going to affect a large surge very much, though as you note, it is there for both noise from the PS and line noise reduction. The line noise rarely makes it through the SMPS conversion and additional filtering and regulation.

> 1 to 3 second flickers [...] just enough to blink all the appliances and set the clocks to flashing

That sounds like a voltage drop caused by a power-hungry device that was turned on somewhere (fridge, air conditioning, coffee machine etc.). Such effects can be quite visible if the cabling in or to the house is inadequate. I guess it could be a problem on the supply side, too, in some countries.



Try a power hungry neighborhood when someone hits a power pole during a storm or when lightning takes out a transformer that affects your area.

A high amperage device affects other devices on the same circuit, not the whole house plus your neighbors.

If you think a surge strip is all you need, then have at it. It's your equipment.

> Most do not have varistors for this purpose

I haven't taken any projectors apart but I'd be surprised not to find varistors. They are 10 cent parts and a cheap standard provision for spike suppression. Without any provision for spikes on the supply side, the device would probably not be able to pass typical testing (CE/EMV testing and other testing).

> many surges come from, over signal lines

You seem to be refererring to common mode voltage being related to voltage drops on supply lines. That's possible with grounded devices but a super-rare reason for failure (in my country) because integrated circuits are designed to deal with a reasonable amount of common mode voltage: clamping diodes, resistive termination etc. The right type of UPS can remove the remaining minimal risk but it wouldn't be worth it here, it's just too rare. Local power fluctuations (by a fridge turing on etc.) will otherwise not increase or decrease the voltage inside digital devices because there's always a voltage regulator somewhere. And the AC side of the PSU should have a varistor.

> you can have some increase in voltage across a lamp in a large surge

UHP lamps are probably regulated by current and if they have a responsive type of regulation, there should be no voltage change that lasts long enough to damage the lamp. That's pure speculation, of course.

> when someone hits a power pole during a storm

That would have to be a mole as we don't have poles. With such catastropic incidents (add lightning strike in vincinity of home), all odds are off.

> Most do not have varistors for this purpose

I haven't taken any projectors apart but I'd be surprised not to find varistors. They are 10 cent parts and a cheap standard provision for spike suppression. Without any provision for spikes on the supply side, the device would probably not be able to pass typical testing (CE/EMV testing and other testing).

> many surges come from, over signal lines

You seem to be refererring to common mode voltage being related to voltage drops on supply lines. That's possible with grounded devices but a super-rare reason for failure (in my country) because integrated circuits are designed to deal with a reasonable amount of common mode voltage: clamping diodes, resistive termination etc. The right type of UPS can remove the remaining minimal risk but it wouldn't be worth it here, it's just too rare. Local power fluctuations (by a fridge turing on etc.) will otherwise not increase or decrease the voltage inside digital devices because there's always a voltage regulator somewhere. And the AC side of the PSU should have a varistor.

> you can have some increase in voltage across a lamp in a large surge

UHP lamps are probably regulated by current and if they have a responsive type of regulation, there should be no voltage change that lasts long enough to damage the lamp. That's pure speculation, of course.

I agree with this last point. I was just conceeding that it is a possibility, not likely.

I do take apart projector power supplies all the time, and few have MOVs. Also, MOST of the damage due to lightning, in our area very common, come from ungrounded signal lines on sat systems and antennae. I work on this stuff every day and see the results. We sometimes see power supply damage, but rarely, if ever when decent, basic surge suppression is used and the system is grounded properly.

It is not rocket science. Ground things according to code, use good, basic surge suppression on a.c. and signal lines, and there is no problem. I have been installing and servicing systems for three decades and never see damage on properly installed and protected systems. We rarely use expensive UPS or line conditioning. The basics are sufficient, and lamps are rarely affected. That said, I have had a couple of instances where clients who were not using surge suppression reported lamps going out simultaneously with lightning strike and power outages. Better to be safe than sorry and use good basic practice.

So, lcaillo, in your experience, how often should you replace the surge supressors?

.......
The lamp issue that is most of concern is frequent restarts. Cooling is just not a big issue.

Cooling is indeed a big issue, so as frequent restarts. Don't forget that the lamp assembly is a very good heat reservoir. Once power fails, if cooling is not present, this heat reservoir is more than enough to overheat the lamp as well as the surrounding electronics to very high temperatures. Repetition of this will inevitably shorten the life of the electronics and the lamp.

> Once power fails, if cooling is not present, this heat reservoir is more than enough to overheat the lamp

If you had an understanding of physics (heat flow and temperature gradients), you'd realize that that's just not possible. The lamp is the heat source, all temperature gradients - with or without fan - are directed away from it. It can not overheat because of power failure. For the lamp, a power failure may be the best thing to happen because it can cool down more slowly than usual, meaning less stress for the quartz wall.

> as well as the surrounding electronics

That's the problem. Heat that normally would have been transported out of the projector by air will now seep into the surrounding components and some (e.g LCD panels) may have little headroom, temperature-wise. But if you see how short the fan cool-down is in some projectors, ie. just seconds, it seems safe to assume that these well-cooled projectors will not need a UPS to deal with the rare power failure. Older projectors that have extended cool down periods are a different matter.

So, lcaillo, in your experience, how often should you replace the surge supressors?

Simple, never, unless they fail. MOVs nearly always fail catastrophically by becoming a dead short. When that happens you throw a breaker or the unit opens if it is UL1449 rated.

Cooling is indeed a big issue, so as frequent restarts. Don't forget that the lamp assembly is a very good heat reservoir. Once power fails, if cooling is not present, this heat reservoir is more than enough to overheat the lamp as well as the surrounding electronics to very high temperatures. Repetition of this will inevitably shorten the life of the electronics and the lamp.

Cooling is a big issue when the unit is running. Upon shutdown, it is mostly a myth that it is critical. I have discussed the matter with numerous engineers at the manufacturers of the lamps (Osram and Philips) and displays (Panasonic, Mitsubishi, Yamaha, Runco, Sony, Hitachi, and others). They all say that the issue is overstated, and that a larger reason for post power cooling is to cool the lamp to alow a quicker restart when needed. The concern with cooling is that there may be some thermal lag that for a few milliseconds may result in increased temperature. This is extremely unlikely as the fans almost always turn for a short period after the arc is extinguished. I have tried to measure thermal lag and found not a single instance where it could be identified, and not a single instance where a fan did not continue to turn after the arc is lost in a loss of power.

It is far more of an issue to have to restart the lamp frequently, as this is where most of the damage occurs. If you have frequent outages, a UPS might make sense. With hundreds of lamp based installations over the years in one of the most lightning and outage prone areas of the US, I have not found any problem with lamp life. We rarely, if ever, use either UPS or expensive power conditioners on these units. It just has not been an issue.

My mantra is "proper grounding and good basic surge protection that covers all signal lines into the system." That is all that is needed in most systems.

Not to hi-jack, but since we're on the subject...I've been wondering how you would incorporate a UPS into a ceiling mount? I was planning on table-mounting my PJ, and of course UPS would have been a no-brainer. However, for the life of me I can't figure out how you'd do it with a ceiling-mount; that is since power cables and extension cords behind the drywall are not code.

CD

Don't bother with the UPS. Just put in an outlet with a surge suppressor built in.

> Once power fails, if cooling is not present, this heat reservoir is more than enough to overheat the lamp

If you had an understanding of physics (heat flow and temperature gradients), you'd realize that that's just not possible. The lamp is the heat source, all temperature gradients - with or without fan - are directed away from it. It can not overheat because of power failure. For the lamp, a power failure may be the best thing to happen because it can cool down more slowly than usual, meaning less stress for the quartz wall.



Projector lamp is a complex device which requires even cooling and also temperature control to avoid overheating of the seals. The forced airflow, by design, facilitates management of cooling of the lamp in addition to cooling down the surrounding electronics. Once power is disconnected, if the fan cooling is not present, the heat stored in the lamp assembly flows back into the lamp which could overheat the lamp seals and further uneven heating would impose more stress on the glass surface. These could easily shorten the life of the lamp.

Many modern projectors require few minutes of managed fan forced cooling to cool down the lamp in a manage way in addition to cooling the surrounding electronics. For example, Sony vw60 requires few minutes of cooling once power is disconnected.

There are some projectors designed to cool with natural convection air flows (once power is disconnected) and do not require fan forced cooling. This is specified by the manufacturers of such projectors, however, this does not apply to the projectors which require managed fan-forced cooling once power is disconnected.

Projector lamp is a complex device which requires even cooling and also temperature control to avoid overheating of the seals. The forced airflow, by design, facilitates management of cooling of the lamp in addition to cooling down the surrounding electronics. Once power is disconnected, if the fan cooling is not present, the heat stored in the lamp assembly flows back into the lamp which could overheat the lamp seals and further uneven heating would impose more stress on the glass surface. These could easily shorten the life of the lamp.

Many modern projectors require few minutes of managed fan forced cooling to cool down the lamp in a manage way in addition to cooling the surrounding electronics. For example, Sony vw60 requires few minutes of cooling once power is disconnected.

There are some projectors designed to cool with natural convection air flows (once power is disconnected) and do not require fan forced cooling. This is specified by the manufacturers of such projectors, however, this does not apply to the projectors which require managed fan-forced cooling once power is disconnected.


Nonsense. A lamp is a simple device that runs very hot. When power is shut off, the arc stops immediately and no further heat is produced. The concern is possible thermal lag, which, according to the makers of the lamps is really not much concern at all, excetp in some extreme cases of very compact projectors with poor airflow designs. Even in those cases, the concern is not a great one.

The manufacturers of the lamps may have a biased opinion ...... ;)

Not to hi-jack, but since we're on the subject...I've been wondering how you would incorporate a UPS into a ceiling mount? I was planning on table-mounting my PJ, and of course UPS would have been a no-brainer. However, for the life of me I can't figure out how you'd do it with a ceiling-mount; that is since power cables and extension cords behind the drywall are not code.

CDThere is at least one other thread with this discussion in it. There is a special outlet that allows you to place a standard outlet in the ceiling and run code wiring down to this inverted outlet. You then plug a standard power cord into the UPS and into the inverted outlet and this allows you to use a UPS/conditioner with your ceiling mounted PJ. It has details for this outlet but I don't remember the thread off the top of my head and I'm multi-tasking at the moment so I haven't searched for it yet.

The best recommendation for surge suppression is to use a whole house supressor rather than the glorified extension cord power strips many people use.

The manufacturers of the sets and the lamp vendors work together and both have an interest in maximizing lamp life. But if you read my post above, you will find that I have spoken to numerous display vendors as well. What you find in each case is that low level technical staff take the position that because the set is designed with post power cooling it is important. Once you get beyond that level to techs with more knowledge on the design matters or to engineers, they tell you that the primary concern with cooling is restart time. A secondary concern is the possibility that there may be thermal lag, but no one has ever measured it and confirmed that it ever happens. They consider the matter not worthy of concern unless there are frequent outages, then the concern is far greater with restart rates than with termal issues. This is a classic case of misunderstandings of the technology being exploited by people selling UPSs and creating a fear that is not useful.

Talk to some manufacturers. You will find that my analysis is consistent. Like I said, however, you need to get beyond low level service techs to get any real info.

You might try measuring thermal lag...just use safety goggles when doing so to protect your eyes and, hint, aim your infrared device at the base of the lamp just under the electrode, not at the arc itself, since its temp will likely exceed your measurement device's range. You will find that the base of the electrode (where your "seal" occurs) drops in temp instantly when the power is disconnected. There is not enough capacity in the lamp supply to sustain the arc for any time at all. During this period the fan is still turning for a very short period of time. There is still convection occurring moving heat away from the arc envelope.

Thanks a bunch, guys....

Anyone have any links for a good, decent UPS?

Thanks

> I've been wondering how you would incorporate a UPS into a ceiling mount?

Why would you want to do that? That's a bit dangerous. They are very heavy. And they get hot (even if inactive). They need cooling when used, ie. a fan will spring on. Just put the UPS in some corner of the room and run an AC cable to the projector. Remember that you'll have to run the other equipement (DVD player, receiver) of the UPS, too, to get full protection.

Recommendation: I've purchased a HP T750 UPS (for my PC) cheaply of ebay. That one would look good in a home cinema because it's black and doesn't have the computer look.

> I've been wondering how you would incorporate a UPS into a ceiling mount?

Why would you want to do that? That's a bit dangerous. They are very heavy. And they get hot (even if inactive). They need cooling when used, ie. a fan will spring on. Just put the UPS in some corner of the room and run an AC cable to the projector. Remember that you'll have to run the other equipement (DVD player, receiver) of the UPS, too, to get full protection.

Recommendation: I've purchased a HP T750 UPS (for my PC) cheaply of ebay. That one would look good in a home cinema because it's black and doesn't have the computer look.

MirkoK, what I meant is how do you UPS protect a ceiling-mounted PJ, not how do you hang one from your ceiling :rolleyes: You can't "just put the UPS in some corner of the room and run an AC cable to the projector" without violating code. Hence the nature of my question, which has been answered.

Thanks,
CD

> heat stored in the lamp assembly flows back into the lamp

No, it won't, repeating it doesn't make it right. It's just physically impossible. Any flow of heat back to the lamp would require that the heat gradient has reversed. Heat can only flow between parts of different temperature, from hot to cold, and the flow is directly proportional to the temperature difference. Gradient reversal is not possible between two parts (lamp; lump of metal next to it) if one of the parts (lamp) is connected only to the other part and has no other route for heat:

The lamp has been heating up the adjacent lump of metal while the projector was on - to a temperature below the lamp's temperature (it's physically imposible for a heat source to heat any adjacent part to a higher temperature than its own). Between lamp and adjacent parts, a temperature gradient is established during projector use and it goes from lamp to metal. This situation does not change just because power is lost: if power is lost, no additional heat enters the system and the gradients play out: heat still flows according to the gradients, from hot to cold, until everything has cooled down to room temperature.

> You can't "just put the UPS in some corner of the room and run an AC cable to the projector" without violating code

I don't know about that, maybe you are right. Guess that depends on the country. I use a 15m extension cable (couple of outlets) from the UPS to the components that need the protecion and didn't think much of it.

> heat stored in the lamp assembly flows back into the lamp

No, it won't, repeating it doesn't make it right. It's just physically impossible. Any flow of heat back to the lamp would require that the heat gradient has reversed. Heat can only flow between parts of different temperature, from hot to cold, and the flow is directly proportional to the temperature difference. Gradient reversal is not possible between two parts (lamp; lump of metal next to it) if one of the parts (lamp) is connected only to the other part and has no other route for heat:

The lamp has been heating up the adjacent lump of metal while the projector was on - to a temperature below the lamp's temperature (it's physically imposible for a heat source to heat any adjacent part to a higher temperature than its own). Between lamp and adjacent parts, a temperature gradient is established during projector use and it goes from lamp to metal. This situation does not change just because power is lost: if power is lost, no additional heat enters the system and the gradients play out: heat still flows according to the gradients, from hot to cold, until everything has cooled down to room temperature.

You are assuming that the lamp will not be cooled down quicker than the assembly which is not correct for all cases. This depends on the design. Also, it cannot be assumed that the assembly and the lamp as a single lump because heat is exchanged through radiation between the lamp and the assembly. If the assembly could absorb heat as a heat-storage (partly through heat radiation), then it would become the heat-source to heat up some parts of the lamp after a power failure. The heat gradient would be reversed and the assembly would become the source and would heat the lamp unevenly which would stress the glass surface and also may deteriorate the lamp seals. In such cases fan is important to cool the assembly, lamp (and also surrounding electronics) while evenly distributing the heat absorbed into the lamp from the assembly.

See, this is why I said the most important reason for me using a UPS for my PJ is that I want to decide when to turn off the PJ and not the sudden loss of power. All other reasons become arguments about things that have been argued on numerous boards for years.

OP:
Do you need a UPS? No.

Should you get one? It's nice to have.

It should be line interactive and have the ability to condition the power going into the PJ. Additionally, it needs to have at least twice the watts capability of the PJ itself.

True sine wave is nice but really only needed for very specific equipment and high end audio.

APC, Tripplite, and Cyberpower are three good names to look for.

Don't bother with the UPS. Just put in an outlet with a surge suppressor built in.

...but I just came across this http://www.panamax.com/Products/In-Wall/MIW-SURGE.aspx#tab_benefits. Looks like the perfect solution for ceiling-mount surge protection. I have one of these Panamax outlets behind my Plasma (without surge protection) and I like the fact that they have a cut-out for HDMI, Cat5, etc.

CD

If you are going to go with just surge suppression, do the whole house - http://www.panamax.com/Products/Other/GPP8005.aspx

While there is nothing wrong with whole house suppression from an a.c. perspective, these units do not protect signal lines into the system. An inexpensive system level device is still a good idea.

While there is nothing wrong with whole house suppression from an a.c. perspective, these units do not protect signal lines into the system. An inexpensive system level device is still a good idea.

They make whole house with phone and coax protection as well.

They make whole house with phone and coax protection as well.


Yes, but by the time you install each, you may end up spending more money. Also, most people don't realize that they are important, and the vast majority of people who install WH suppression never protect the signal lines. With system level protectors that do available as cheap as $20 for a decent one, and superb units like the Panamax at about $80, for most people this is a better alternative. Most consumers should not be messing around in the electrical panel and hiring an electrician adds even more cost. The fact is, you can protect most systems just fine with proper grounding and good, inexpensive system level protectors.

Yes, but by the time you install each, you may end up spending more money. Also, most people don't realize that they are important, and the vast majority of people who install WH suppression never protect the signal lines. With system level protectors that do available as cheap as $20 for a decent one, and superb units like the Panamax at about $80, for most people this is a better alternative. Most consumers should not be messing around in the electrical panel and hiring an electrician adds even more cost. The fact is, you can protect most systems just fine with proper grounding and good, inexpensive system level protectors.Yes, and then you will get a surge protector fire since the consumer went the cheap route and or they had a bad neutral in the house. For individual applications, it would be better to use a series type surge protector rather than a shunt type anyway.

Yes, and then you will get a surge protector fire since the consumer went the cheap route and or they had a bad neutral in the house. For individual applications, it would be better to use a series type surge protector rather than a shunt type anyway.

I have been installing MOV based units and servicing systems in high lightning areas for nearly three decades and have not seen anything of the sort. It is even less likely now with UL1449. Few series type units have protection for signal lines. Once again, good grounding and good basic surge suppressors that cover the signal lines are all that most systems need.

I have been installing MOV based units and servicing systems in high lightning areas for nearly three decades...

Well at least I can now understand your subjectivity.

But, I can't discount your experience so let it stand for what it's worth and we'll let people decide anyway.

I am not an expert, but people on this forum that I trust told me to get a UPS that put out a true sine wave. I bought this one--a bit overkil, but...

http://www.provantage.com/apc-sua1000~7AMPU032.htm

all consumer grade ones should be true sines, as they are offline style UPS. A large relay kicks over at the moment of failure (the AC power acctualy holds the relay, loss of it lets the relay collapse and enable the battery side) Offline's don't use the battery or the DC-AC converter circuits unless there is no AC power coming in. OnLine UPS's are always feeding power off the battery, there is zero lag in change over, unlike offlines which have a few milliseconds lag. not enough to bother 99.9% of things.

Well at least I can now understand your subjectivity.

But, I can't discount your experience so let it stand for what it's worth and we'll let people decide anyway.

The vast majority of what you read here or anywhere else is subjective and based on the experience and perception of the poster. I am no exception. Neither are you. When possible I post facts and infomation based on actual experience.

I have been researching surge suppression to provide best practices in proteting our clients' systems for many years. We try to do so with the best value and highest efficacy. For the past 8 years I have been servicing systems for a dealer who installs the kind of protection that I have suggested nearly 100% of the time. I have yet to see one of his systems damaged when properly connected. What we see rather frequently are sat receivers, cable boxes and connected equipment damaged on the tuner and input sides when cable and sat installers disconnect the signal line protection and/or do not ground their system properly.We never see damage on the PS side with decent a.c. suppression with MOVs installed. I see lots of equipment that we don't sell that was not protected come in for service, however.

The trends are so obvious that I have to conclude that our practices have been effective. Others can decide for themselves, as you say. I can only relate my experience and facts that I have. One such fact is that UL1449 is in place to assure that fires that you suggested were a possibility cannot occur. Even before that, I simply never saw one, though I have seen some severely damaged protectors.

The vast majority of what you read here or anywhere else is subjective and based on the experience and perception of the poster. I am no exception. Neither are you. When possible I post facts and infomation based on actual experience.

I have been researching surge suppression to provide best practices in proteting our clients' systems for many years. We try to do so with the best value and highest efficacy. For the past 8 years I have been servicing systems for a dealer who installs the kind of protection that I have suggested nearly 100% of the time. I have yet to see one of his systems damaged when properly connected. What we see rather frequently are sat receivers, cable boxes and connected equipment damaged on the tuner and input sides when cable and sat installers disconnect the signal line protection and/or do not ground their system properly.We never see damage on the PS side with decent a.c. suppression with MOVs installed. I see lots of equipment that we don't sell that was not protected come in for service, however.

The trends are so obvious that I have to conclude that our practices have been effective. Others can decide for themselves, as you say. I can only relate my experience and facts that I have. One such fact is that UL1449 is in place to assure that fires that you suggested were a possibility cannot occur. Even before that, I simply never saw one, though I have seen some severely damaged protectors.

It sounds like you definitely have a good system for making sure customer's power supplies are properly setup. I have seen so many personal and business setups that were running on systems that had severe problems and was costing them time after time.

Surge suppression sounds like it has improved over my dealings with most MOV devices several years ago when I decided to move away from them due to repeated problems and lack of real protection. I guess I need to re-investigate to see how these improvements have helped.

Thanks for the info and sticking with the conversation.

all consumer grade ones should be true sines, as they are offline style UPS. A large relay kicks over at the moment of failure (the AC power acctualy holds the relay, loss of it lets the relay collapse and enable the battery side) Offline's don't use the battery or the DC-AC converter circuits unless there is no AC power coming in. OnLine UPS's are always feeding power off the battery, there is zero lag in change over, unlike offlines which have a few milliseconds lag. not enough to bother 99.9% of things.Offline UPS's are not going to work for a PJ setup. If you go back to previous threads on this subject you will find that several people had their PJ shutting off when using an offline UPS. Most consumer UPS's are not true sine wave. There are a few instances where equipment will not handle squre or modified square sine wave but PJs should be fine. If you go UPS, get a line interactive model that also conditions the power. Residential power can be very unreliable for consistent clean power.

Here's a short summerized explanation of UL 1449 (http://downloads.eatonelectrical.ca/downloads/Transient%20Voltage%20Surge%20Supp/Tech%20Data/TVSS%20UL%20spec%201449.pdf) for anyone interested.

My lamp just premature exploded 2 weeks ago. Not once was I asked by manufacturer if the unit was plugged into some kind of device like a UPS. Maybe if they thought it could have prevented the blowout, they would have recommended one? I ask because I don't know. I guess I'll continue on without one???

My bulb (approx 1000 hours) went out 2 weeks ago and currently, I have my PJ plugged in the wall outlet directly. I was wondering if it was due to a 'bad' power or something. Could I have avoided that by using a power conditioner or a UPS, etc?

What are you guys using as far as power is concerned?

Thanks
Frag


I'm a firm believer in a high quality UPS/power conditioner. I have a TrippLite double conversion UPS and I've never had any problems with my projector lamps. Projector ballasts and lamps love clean power and the TrippLite does a great job.

As indicated previously, pure sine wave is not essential for some power supplies. This depends on the design of the power supply. For example, PC power supplies do not need pure sine wave, it will operate with simulated sine wave which is modified square wave. People should be careful that if they need pure sine wave (which is safer) to check the specs whether it is indeed pure sine wave. In some cases, simulated sine wave is specified as sine wave although it is not pure sine wave.

I'm a firm believer [...] Projector ballasts and lamps love clean power
That's an expensive belief. A UHP lamp's ballast/circuit neither loves nor needs "clean" mains power because mains power does not power the lamp directly. A PCB in the projector generates the projector's own, stable, regulated lamp voltage. Call it "conditioned" and "clean", if that makes you feel happier. A UPS can get you over a power loss. That's all. It is not going to extend the life of the lamp, improve the color spectrum or do any other magical things. The ability to get over a power loss is convenience for most users. For some. it is a necessity because their projector's components would otherwise be damaged. I suggest you decide by looking at the regular cool-down of your projector. It lasts 5 seconds? UPS is a convenience. It takes minutes? Install a UPS.

The length of the cool down cycle of the projector is irrelevant. A UPS is a convenience, unless you have LOTS of outages and want to avoid the restarts. Lamp aging and damage due to power outages is simply and overstated worry. Otherwise your statements are quite correct. The SMPS and ballast provide all the filtering needed for the lamp, or for the rest of the circuits.

> The length of the cool down cycle of the projector is irrelevant

I disagree. If there is no fan to push out the remaining heat stored in parts with high thermal capacity, that heat will seep into the adjacent components and go where it wouldn't go if it had a path with less thermal resistance (like aluminium fins cooled by air flow). Whether that's a problem or not should depend on:

a) the margins components have for heat. Components in older models will have a lower margin (organic panels rather than inorganic; less advanced electrical components, for example no solid aluminium-polymer capcitors).

b) the actual amount of heat that is left in the cooling system. Older projectors were, on average, heavier than current models, therefore have a higher heat capacity (specific heat capacity multiplied with mass). Wattage/lamp type would have to be considered, too.

> The length of the cool down cycle of the projector is irrelevant

I disagree. If there is no fan to push out the remaining heat stored in parts with high thermal capacity, that heat will seep into the adjacent components and go where it wouldn't go if it had a path with less thermal resistance (like aluminium fins cooled by air flow). Whether that's a problem or not should depend on:

a) the margins components have for heat. Components in older models will have a lower margin (organic panels rather than inorganic; less advanced electrical components, for example no solid aluminium-polymer capcitors).

b) the actual amount of heat that is left in the cooling system. Older projectors were, on average, heavier than current models, therefore have a higher heat capacity (specific heat capacity multiplied with mass). Wattage/lamp type would have to be considered, too.

Yes, fan cooling is important to cool down the projector components after shut down. If not, the temperature of some components could rise well above the operating temperatures reducing the life time of those components.

Some projectors are designed in a way that they do not need fan cooling (after shut down) as they use natural convection air flows for cooling, however, this does not apply to other projectors.

Yes, fan cooling is important to cool down the projector components after shut down. If not, the temperature of some components could rise well above the operating temperatures reducing the life time of those components.

Some projectors are designed in a way that they do not need fan cooling (after shut down) as they use natural convection air flows for cooling, however, this does not apply to other projectors.

Do you have some evidence of this? I have measured the temps at shutdown on numerous fan cooled sytems and found no evidence of thermal lag. The temp drops whether the fans fun or not in every case.

Do you have some evidence of this? I have measured the temps at shutdown on numerous fan cooled sytems and found no evidence of thermal lag. The temp drops whether the fans fun or not in every case.

Some components of the projector, e.g. the lamp assembly, would act as heat storage devices. Once the main heat source, i.e. the lamp, is switched off, these will start radiating heat while raising the temperature of the other components above the (fan cooled) operating temperature, if the fan is not working after switching off the main heat source.

This is basic physics. There are few posts above, explaining further.

If you ask me whether I have measured this, no I haven't.

Some components of the projector, e.g. the lamp assembly, would act as heat storage devices. Once the main heat source, i.e. the lamp, is switched off, these will start radiating heat while raising the temperature of the other components above the (fan cooled) operating temperature, if the fan is not working after switching off the main heat source.

This is basic physics. There are few posts above, explaining further.

If you ask me whether I have measured this, no I haven't.

This simply does not happen in any set that I have worked on. Have you ever measured temp in projection devices? I have. In every one that I have measured the lamp assy temp drops immediately and rapidly when the power is cut off. What you describe is an assumption, not basic physics. Thermodynamics requires that there be a source of energy for heat. The source when powered is the lamp arc. When power is removed, the arc stops and the lamp temp drops very rapidly. I have not been able to measure any thermal lag even immediately surrounding the arc tube.

> The source when powered is the lamp arc. When power is removed, the arc stops and the lamp temp drops very rapidly

Irrelevant. It was never claimed that the bulb plays any role in a power-loss scenario. Obviously the bulb can not overheat and it will drop in temperature relatively quicky because its mass and thus its heat capacity is low. What matters is the amount of heat stored in massive parts (lamp assembly etc).

> What you describe is an assumption, not basic physics

That was as basic physics as it gets. In a projector without fan, heat transfer is primarily based on conduction (rather than convection or radiation). Heat flows between components that are not in thermal equilibrium. The flow of heat is described by the heat equation. That means that the flow of heat is proportional to the thermal conductivity of ajacent components (k) and the difference in temperature between these parts (dt). Therefore, heat follows the heat gradients to the cooled parts in a running projector. When the fan stops, cooling of these parts stops. When the capacity of the cooled parts next to the hot lamp assembly is exhausted, heat will seep into other components that were previously protected by the artifical heat gradients generated by cooling.

If and when that happens depends on the construction. If the previously-cooled parts are massive and/or relatively cool, they may be able to sink all excess heat remaining in hot parts. Otherwise, some heat will flow to electronics and optics. The only assumption I make is that the projector's engineers know their cooling system. If they force it to go through a 5 minutes cool-down, my assumption is that there is too much heat to just let the projector reach an equilibrium.

Have you ever actually made any measurements on projectors? I have, and you are mistaken.

> Have you ever actually made any measurements on projectors? I have, and you are mistaken.

Well, post them. Let's see the figures. As to your measurements, I'd like to know which projectors exactly you have examined (any projector relevant to this sub-discussion, ie. with a long fan cool-down period?) and what you have measured, where and how, ie. type and precision of sensors.

I don't care to open my own projector to verify basic physics. That's like somebody asking me "have you ever opened your calculator and made any measurements to verify that 1 + 1 = 2?".

As to my qualification: I have designed my own microcontroller-based PID controller (temperature controller) which can, of course, take temperature measurements. It connects to various types of temperature sensors, from calibrated high precision ZACWire sensors, over 1-Wire sensors and KTY sensors to Type-K thermoelements. I believe I have some understanding in temperature matters without opening projectors.

This is a silly argument. The lamp is the source of heat and projectors are not designed to sink that heat. Once the lamp arc ceases, there is no source for heating. I have worked on hundreds of projectors and made dozens of measurements to try to better understand the thermal issues involved. There simply is no source of heat to cause further increases in temperature. The physics IS simple. What you propose violates the laws of thermodynamics. If you believe otherwise then act on your assumptions. You will do no harm, but others should understand that your ideas are simply incorrect and not base their decisions upon them. Enough...I am done with this discussion. You may have the last word on the matter if you choose.

> Once the lamp arc ceases, there is no source for heating

Irrelevant. If the arc is off, no additional energy enters the system but the hot parts are still a perfect source of heat for other components until the temperature in the entire projector has equalized (second law of thermodynamics; entropy). How much of a heat source? That depends on the mass, temperature and heat capacity of the hot parts. Maybe you'll understand it better with an analogy:

Heat up an oven but leave the kitchen window open. The oven will get hot but the kitchen will remain fairly cool, thanks to the window. Turn off the oven but close the window at the same time: the oven will be a heat source to the room.

While the fan was running, sensitive components were shielded from overheating because all heat flowed according to the temperature gradients, ie. ultimately to the cooled parts and from there out of the projector's "window".

As soon as the fan stops, heat equalizing begins: some components warm up as much as others get cooler (first law of thermodynamics). A stopped projector is not a perfectly closed system, so on top of that, a slow loss of heat by convection through fan openings continues over hours.

> You may have the last word on the matter if you choose.

Hope so.

The so-called AV Tech's comments notwithstanding, MirkoK is absolutely right.

If your PJ's fan runs for some period of time after you "turn it off", then it does so for a reason (to evacuate the heat). If you suffer a power failure, and don't have a UPS, then that fan will not run, and it will not evacuate the heat away from the electronics. Although this is not likely to kill your PJ dead in one, or two, or even many multiple occurrences, over time this will fry your panels and filters and anything else plastic and/or susceptible to heat.

The fan is there for a reason. It runs after "shut-off" for a reason. If you have frequent power failures in your area, or otherwise want to keep your PJ "pristine" and unlikely to suffer damage from a power failure, you will get yourself a UPS. I have the Belkin AP30800-10, one for each of my two LCD projector setups.

All modern sets use thermal protection that will not allow the set to restart a hot lamp. Power supplies use a SMPS design that is typically very robust with respect to sagging power, and will have no problem with short term drops. When it drops too low the set will simply shut down.

The lamp issue that is most of concern is frequent restarts. Cooling is just not a big issue.


Is this true for PJ's?
Such as my newly aquired Planar pd7150?
PPL has had four 30second to one miunte outages in the past few weeks and each time my tv starts back up in a purplish haze that is usually corrected when my D* HD-DVR finishes downloading.
But I'm concerned that my PJ would try to re-light itself?

> But I'm concerned that my PJ would try to re-light itself?

Why are you concerned? UHP lamps have hot re-strike capability. The only problem is: The re-strike voltage of a hot high pressure discharge lamp is significantly higher than the normal strike voltage. Therefore, a projector may not be able to re-strike a hot lamp until a few seconds or maybe a minute have passed. Its "ballast" just may not have the juice. That's the only reason for any waiting. "The lamp must cool down after being extinguished until the pressure drops to a value at which the lamp can be ignited with the usual level of ignition voltage" (www.freepatentsonline.com/WO2007132369.html is an interesting read). A ballast can be designed for a hot re-strike within 1-10s - google for UHP ballast patents. But it's probably cheaper to design a ballast for a re-strike in 30s or so because in that case no special voltage is required. Other than that delay, there is no problem. A hot re-strike isn't going to destroy the lamp. The forum myth that projectors are required to sit for an hour or so before re-strike is bollocks. Personally, I'd rather restrike as early as possible to avoid a stressful hot-cold-hot cycle.

The forum myth that projectors are required to sit for an hour or so before re-strike is bollocks. Personally, I'd rather restrike as early as possible to avoid a stressful hot-cold-hot cycle.

This would require establishing the fact that you are recommended to allow the lamp to cool for awhile before restriking as a myth, not just your statement. I am glad you remarked on your personal preference as that's something we can respect.