Inverter for HT projectors??

[harshi_n]

Do we need inverters for projectors in case we already have one for the house ?
In general do ppl use a separate inverter for projector?
I read sinewave inverters are the best for the projectors.Is it true?
What would be cost of it ?

Please post your views on the same.

 

[sash]

This question has bothered me for some time. In my home, i have a sine wave ups (850 va, microtek) but i observed that the TV blinks when the power goes and comes back. Then i changed a setting at the back of the ups (there is a button that says at what voltage the ups should kick in and you must set it higher so that ups kicks in sooner). After that i have never really "felt" the power going off. From my research on projector maintenance, i have learnt that what really matters is that the power to the pj is still on when you turn it off (for Epson, you press standby) so that the pj can cool the lamp. In that context i'm thinking it may not matter if the power goes off for a second and then comes back on.
With my setting, i'll test some more and let you know what is happening at present. i don't have a desktop to test the power-goes-system-reboots scenario. But i have a settop box which doesn't restart.
I hear that the best solution is the "sine wave online ups"

 

[m.a.sara]

Generally projector owners have back up for their projectors mainly for this reason - In the event of a sudden power cut, pj needs to be shut down properly and they need a UPS with a few mins of back up for PJ.

If you are in the same boat, you can buy a UPS(APC or microteck with 1KVA -1.5KVA depending on ur pj's power req) for around 6-7k and it should give you a peace of mind.

I've a quasi sinewave APC UPS (1KVA) that is used just for this purpose. cost about 6k. I am not using my other home UPS as its only 800VA.

If you already have a home UPS with more power (say 2KVA or something) you can test your pj and decide if its having enough juice to provide backup for ur pj.

 

[GeorgeO]

harshi

You dont want to run the risk of the inverter tripping when/if there is a blackout. I have a dedicated pure sine wave online UPS(APC Backups 3KVA) for my HT room and a Sukam inverter for the rest of the house

 

[sash]

How do i know whether my ups is enough for my projector or not? I mean sure i can trip the power and check but is there a way to calculate?
Say i have 800VA inverter. How can i know from the wattage of the devices?
Can someone please let us know if you already have this knowledge?

 

[baijuxavior]

We can assume 60-70% efficiency for UPS. So a 800VA UPS can handle 500W easily. I don't think a projector is a power hungry device. I am running Denon AVR, Subwoofer, HTPC, TV and two STBs on a 1.2KVA UPS. Never felt any overload problem. With 40AH battery it gives me 45 minutes backup on full load. Instead of inverters which have a higher changeover time, use a UPS. Some inverters have UPS mode.

 

[harshi_n]

I need to check my home inverter but its good to with like 750VA just for the projector like the one below ?

APC Inverter :: APC UPS :: APC Inverter Prices & Offers :: APC Smart-UPS

 

[baijuxavior]

What is the power consumption of the projector? For projector alone the 750VA UPS will be sufficient.

 

[just4kix]

Inverter will not help for projector. The power switch must be instantaneous that can only be provided by an online UPS.

Normal inverter and UPS Operation
When the AC power is on, it is fed directly to the circuit. A transducer is continuously sensing whether AC power is in supply or not. During this time, the batteries are charging. As soon as the AC power switches off, the transducer senses the loss and triggers the relay to switch to battery. The battery is connected to an inverter that converts DC to AC. There is half a second or less delay between the switchover. This delay is OK for general appliances but will cause computers, projectors, and other such sensitive equipment to trip. The inverted sine wave is not a pure curve and has a squarish format.

Continuous or Online UPS
Unlike the inverter based UPS, the online UPS always sources AC power from the inverter, even when mains AC is ON. The AC power is charging the battery all the time and is never directly sent to the output. The battery is connected to an inverter that converts DC to AC. This (inverted) power is fed to the house supply. Thus there is zero delay at the switchover (I mean delay is non-existant). Further, pure wave sine wave inverters have additional circuits to shape the AC to as smooth a sine wave as possible.

 

[GeorgeO]

True.But the APC units though not pure sine wave respond fast enough to keep equipment running-including projectors. I know-I've used one for a projector.

 

[just4kix]

True.But the APC units though not pure sine wave respond fast enough to keep equipment running-including projectors. I know-I've used one for a projector.

Pure sine wave or impure sine wave is just another attribute of online UPS. Online UPS could be quasi-sine wave too.

 

[GeorgeO]

You're right of course. What I meant to convey was that you need a suitable back up power source that allows adequate cooling and then shut down to prolong bulb life. While pure sine wave online is the best solution, it could be others as well.

 

[arunsankar]

This question has bothered me for some time. In my home, i have a sine wave ups (850 va, microtek) but i observed that the TV blinks when the power goes and comes back. Then i changed a setting at the back of the ups (there is a button that says at what voltage the ups should kick in and you must set it higher so that ups kicks in sooner). After that i have never really "felt" the power going off. From my research on projector maintenance, i have learnt that what really matters is that the power to the pj is still on when you turn it off (for Epson, you press standby) so that the pj can cool the lamp. In that context i'm thinking it may not matter if the power goes off for a second and then comes back on.
With my setting, i'll test some more and let you know what is happening at present. i don't have a desktop to test the power-goes-system-reboots scenario. But i have a settop box which doesn't restart.
I hear that the best solution is the "sine wave online ups"

This button on the back is ups mode found on home inverters these days. Compared to inverter mode, ups mode offers low changeover delay and hence you're not seeing the flicker anymore.

Between, I have a Sukam 800VA as home ups and a dedicated APC 1KVA for HTC room. The setup has never failed on me with a PJ, 7.1 and an HTPC running on it. :thumbup:

Sent from my GT-P3100 using Tapatalk HD

 

[rshri]

This button on the back is ups mode found on home inverters these days. Compared to inverter mode, ups mode offers low changeover delay and hence you're not seeing the flicker anymore.

I have always wondered why inverters have such a switch. Why don't they just manufacture inverters with low changeover delay? Is low changeover delay harmful to battery in some way, thus giving option to user to switch to high changeover delay?

 

[arunsankar]

I have always wondered why inverters have such a switch. Why don't they just manufacture inverters with low changeover delay? Is low changeover delay harmful to battery in some way, thus giving option to user to switch to high changeover delay?

It's not because of that. In ups mode, other than the changeover delay there is also difference in voltage range which triggers ups. For eg. My Sukam 850 has a lower cutoff of around 180V in ups mode but inverter mode has a cut off much below that may be around 150V. Now in places were voltage is not consistent, ups mode may drain more battery. So, this is given as an optional feature. For those who don't have any sensitive loads on their home inverters, they don't need to switch over to ups mode.

Sent from my GT-P3100 using Tapatalk HD

 

[rshri]

It's not because of that. In ups mode, other than the changeover delay there is also difference in voltage range which triggers ups. For eg. My Sukam 850 has a lower cutoff of around 180V in ups mode but inverter mode has a cut off much below that may be around 150V. Now in places were voltage is not consistent, ups mode may drain more battery. So, this is given as an optional feature. For those who don't have any sensitive loads on their home inverters, they don't need to switch over to ups mode.

Thanks for the explanation! Its makes sense now

 

[sash]

I checked out two APC online ups' at Reliance digital today. One is 600 va and costs Rs. 5000. Another is a sleek model called 850 va and costs Rs 7400. Both come with inbuilt battery. If used exclusively for the PJ even the 600 va is good enough as it can support up to 400 watts for 15 mins or so.
Do other equipment (Receiver etc) also absolutely need UPS? What do you guys think?

 

[GeorgeO]

No. None of the other equipment has a bulb that needs to be cooled by a fan during the powering down process. However protecting other equipment, some of which may also be fairly expensive is a different reason to have some form of "clean/reliable power", not necessarily in the form of a UPS, though.

 

[k2max6]

I checked out two APC online ups' at Reliance digital today. One is 600 va and costs Rs. 5000. Another is a sleek model called 850 va and costs Rs 7400. Both come with inbuilt battery. If used exclusively for the PJ even the 600 va is good enough as it can support up to 400 watts for 15 mins or so.
Do other equipment (Receiver etc) also absolutely need UPS? What do you guys think?

Do you have the model numbers with you because the rates seem to be on the higher side. A non-sinewave 600VA ups from APC costs around 2500 and 1 KVA around 4500.
It would be better if you look at pure sinewave options.

 

[arunsankar]

I checked out two APC online ups' at Reliance digital today. One is 600 va and costs Rs. 5000. Another is a sleek model called 850 va and costs Rs 7400. Both come with inbuilt battery. If used exclusively for the PJ even the 600 va is good enough as it can support up to 400 watts for 15 mins or so.
Do other equipment (Receiver etc) also absolutely need UPS? What do you guys think?

The answer depends on the sensitivity of your equipments to variations and line noises. For example, my PC when directly driven from my home ups, shows a great amount of wavy noise on PJ which is terribly annoying. This is completely gone when the PC is connected to the HT ups. Its because my SMPS is very much sensitive to line noises. Also, my S750 subwoofer creates a loud thud on abrupt power failure which I believe will reduce the life of its diaphragm. So I've connected all these to a 1KVA APC ups which is working great :thumbup: