Ups

triumph

Standard Member
Have just been looking at a Trust UPS rated at 400va in my local Maplins
store, with a view to protecting the bulb in my pj tx 100 which uses 220 watts. Any of you technical bods out there, know if 400va will be adequate
and for how long will it power my pj
 

KraGorn

Novice Member
Well, it's 40 years since I did this at school :), but IIRC

Watts = Volts * Amps

Now, I've always believed a 400va UPS can deliver 400 Volts at 1 Amp for 1 hour .. so allowing for your projector consuming a bit more than 220W I'd expect it run for maybe 20 mins.

A PC typically consumes 300W or more when running hard, so if the spec. indicates the amount of time it'll run a PC then a projector will run a bit longer.

I think. :rolleyes:
 

PJTX100

Distinguished Member
Leaving aside the debate on whether a UPS is OTT anyway...

Any UPS which can't cope with 220W for a minute or so (hich is how long the fan runs on in the TX) 'aint worthy of the title UPS! I'm sure it should be fine, and KraGorn's general knowledge gets more impressive by the day... ;)
...PJ
 

triumph

Standard Member
Many thanks Kra Gorn, since posting, I have been browsing the forums and apparently
there are issues regarding the clipped sine wave output of budget UPS and their
potential to damage the cicuitry of a projector. solve a problem and another one
arises, ain't life a bitch!
 

explicitlyrics

Active Member
From a physics degree point of view, there is no way that a clipped sine wave would damage a Projector. This is besides the fact that the UPS only supplies power when the power is broken (i.e. only a few mins). I have had a 1200Va UPS on my projector for a couple of months now and have not had a powercut while watching, however for some reason quite a few things have blown the RCD recently. Basically, I bought my UPS from ebuyer.com for £46.99 inc P+P + VAT and it seems very effective. Go for it and save the bulb! :)
 

zoolap

Novice Member
triumph said:
Many thanks Kra Gorn, since posting, I have been browsing the forums and apparently
there are issues regarding the clipped sine wave output of budget UPS and their
potential to damage the cicuitry of a projector. solve a problem and another one
arises, ain't life a bitch!
Yup... I've joined this line of question in the past and read so many different things on different here and avsforums. I eventually arrived at the conclusion that it may be better to get a surge protector with mains conditioning and rely on the fact that you don't switch on the projector for about an hour after power loss.
 

PJTX100

Distinguished Member
zoolap said:
Yup... I've joined this line of question in the past and read so many different things on different here and avsforums. I eventually arrived at the conclusion that it may be better to get a surge protector with mains conditioning and rely on the fact that you don't switch on the projector for about an hour after power loss.
Double yup.
Read the same stuff. I do think a UPS is a bit OTT, having seen the PJs in work abused so much and they keep on smiling anyway... Happened to have a power cut at home just before xmas, while PJ in full flow. Has lived to tell the tale... but how much life has it sapped...? worry worry worry :devil:
...PJ
 

explicitlyrics

Active Member
PJ, the projectors at work are business projectors that are probably designed to cope with it better. Dont have any reasoning behind it but it is my suspicion that the designers are aware of the problem and have specifically minimized this danger.
 
M

monopole

Guest
An InFocus engineer on avsforum said that the bulb will not suffer at all if it is not cooled down by the fan. What *will* kill your bulb is restarting the projector while the bulb is still warm - this is the main reason why the fan continues to run when you turn the projector off - to minimise the chance of a warm restart.
 

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