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UPS and Pure sine wave inverter? [Archive] - Event Photographer Society Forum

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Chris Clarke
16-05-2012, 09:49 AM
Firstly

I am new to the Forum so hi to one and all.

My questions stems around remote coverage.

I know that i need a generator and until now had been intending to use a lpg pure sine wave . If however I run the current through a UPS does that in fact negate the need for pure sine wave .

Will an ordinary generator ( albeit quiet and with lpg) be ok?

Stuart Morley
16-05-2012, 10:06 AM
Depending upon using the correct UPS you won't need a pure sine wave generator.

http://www.systeminsight.co.uk/web/articles/ups---an-overview.html

Stu

www.systeminsight.co.uk

Michael Martin
16-05-2012, 10:31 AM
Welcome Chris.

When considering a genny, think about what you will eventually run from it and plan for that. If only a laptop then you don't need a UPS either as your charger acts as the barrier. If you want to run a desktop and several viewing screens and a couple of printers, battery charges and other stuff then a sine wave genny is the way to go. Many folks use the Honda 20is which is an excellent and very quiet machine. There is also the cheaper Kippor which is a Chinese clone but not as quiet I believe. I have an SDMO with the same Honda engine as the 20is but it is very noisy. Last weekend the food van next to me had a Honda 30is which was whisper quite though they are expensive and perhaps over kill in power terms, also heavy.

LPG is cheaper to run but more expensive to buy and a few venues now insist on NO petrol ones. If I were buying a new one now it would be a Honda 26is with LPG, though they are much heavier.

alan_potter
16-05-2012, 10:57 AM
Hi Chris

Just adding my bit. I also run the Honda on LPG the eu20i but now have 2 of them that can be bridged if needed to give double the output if needed also great if I have more than one function that needs power or a smaller event that requires less. Great to carry as take up little space. And on the plus I have a backup in case anything happens not that I have ever had issues with a Honda genny


Alan

john wright
16-05-2012, 11:46 AM
Hi Chris

I've just done a lot of research on specifying a large battery/inverter/UPS system for my van with a generator backup. The system is capable of running a print station and 6 viewing stations for 12 hours between charges. One of the things that failed to work when running from square wave or modified/quasi sine wave was a smaller secondary UPS attached to the main system.

My research (and experience) of inverters is that modified sine wave will work for 95% or thereabouts of electronic equipment. Modified sine wave will usually not work with some inductive loads (motors, fluorescent lights etc.) The cost difference between modified versus pure sine wave inverters is significant and it can be cheaper to test all equipment you intend to run and replace with equipment which is modified sine wave compatible. However, there is a further consideration, because of the way modified sine wave inverters work they tend to be very efficient (usually 95% or better) but this is at a cost of lower efficiency in the load devices. This load inefficiency can be very significant and is dependent upon the type of power supply in the load unit. Pure sine wave inverters on the other hand tends to less efficient (90-95% some as low as 85%) but there is no further efficiency loss in the load devices (other than their stated loss) caused by the waveform type.

The system we are purchasing will use a pure sine wave inverter and a pure sine wave generator. The generator is for back up only and is a a Machine Mart suitcase job (great value alternative). The generator is already purchased and has been used at a couple of events with no issues. Our intention is that we will not use the generator at all and be running purely from battery. The generator will probably be converted to lpg shortly.

Unfortunately the choice of pure and modified sine wave is not straight forward and depends very much on your intended load and the load characteristics.

Back to the original question. Do you still need UPS with a generator (sine wave or modified sine)? The first time the genny runs out of juice then the answer is a definite yes. Does the generator need to be pure sine wave? Depends upon the UPS used but for UPS generally yes.

John

Chris Clarke
16-05-2012, 12:33 PM
Thanks Guys- very helpful.

Stu ,

I assume that you are obviously talking about getting an online UPS and that is something i will look at .

I had obviously spoken to the generator people as well and needless to say they put the fear of god into me about the spec i would need
and were all suggesting the Honda EU 65is which with a lPG converter was over 3k. The Honda 20 iS is a lot better priced but i need to work out whether the output would be sufficient,.

Thanks for your help so far

Richard Chaff
17-05-2012, 08:54 AM
The first time the genny runs out of juice then the answer is a definite yes.

John

Just to note that if you are running lpg this is not an issue. :)