Ordering 250KVA

Sep 01, 2015 44 Replies

Hi, Want to ask a quick question. Please excuse my lack of knowledge but i was told before ordering a stand by generator this size , i need to specify to the supplier certain things.



can i just buy 250kva stand by generator that runs on disel or do i have to explain how and what should come with it. Kindly advice. Thanks.


That's quite a big generator. Is that ordering to buy, or ordering to hire? If the latter, I would *hope* the hire company might talk you through some of the issues.

Are you sure that you have the decimal point in the right place?

250kva will power a small industrial site and consume ~50L an hour. You will need a sizeable fuel storage tank to go with it!

Domestic kit typically tends to be in the 2-10kva range.

To put that into context, my car has a range at motorway speed of about 750 miles on a 60 litre tank so I'd have to drive at 70 mph for about 9 hours to use up that amount of fuel. So a 250 kVA generator is using up diesel at about 9x the rate of a standard car bombing down the motorway.

I think you definitely have got your decimal point in the wrong place :-)

sounds like you've no idea what you want. We can't tell you until you tell us.

NT

Or the person issuing the instruction, of course!

hour.

Diesel has roughly 10 kWhr of energy per litre.

250 kVA output at say 60% effciency requires over 400 kWhr input (assuming 1 kVA = 1 kW, which it may or may not do depending on the load). Divide by 10 to get litres = 40 plus l/hr...

If you where driving down the motorway with your right foot hard on the floor all the time you would have a better comparison. Also bear in mind that 250 kW is also about 350 bhp, so hardly a "standard car"...

You could run a half decent electric shower, though.

Cheers

A 2500l bowser by the sound of it.

And with a 250 kVA generator you could turn the water from a fireman's hose to steam!

I remember when many of the villages round here had to go onto local generators while some work was done on the supply, there were generators in cabinets about the size of a car - and that was one genny for about every 20 houses.

we had a 60kVA genny all to ourselves last summer when the cable under the road died.(it was helped on its way a building site down the road who shorted it out)

Hum, take 1 l of water at 15 C and end with steam at 100C I make to require 2616 kJ. A decent firehose delivers around 10 l per second. So thats 26 MJ or 26,000 kW.

Remove the requirement to turn to steam and you only need 356 kJ per l. A more manageable 3.5 MJ 3,500 kW.

I think, those numbers look rather big but 10l/sec is a lot of water(*) and water takes a lot of energy to heat and even more to turn to steam.

(*) Will fill a 1 metre cube IBC in 1 min 40 seconds.

People do seem to be getting more and more powerful showers. Quite why I don't know. Do they use them hotter and hotter? Do they want a torrent or waterfall in their bathroom? Why hasn't the meddling EU limited them like hairdryers and vacuum cleaners?

When an Irish electrician f***ed up the wiring at the high school I worked at (during renovations and extension), he shorted one of the incoming phases causing a small fire, and burning out the cable. While the EB replaced the cable, we used a three phase generator the size of a lorry. I don't know what the specs of it were.

It's for his big weed growing rooms.

You don't buy these, you hire them. And generally that means you're either a REC, a film studio, an NHS Trust or the Royal Navy submarine division. None of whom have ever had recourse to uk.diy before.

(I had a friend who worked delivering these :-) )

Seconded.

I can run my home quite happily from a 7.5KVA generator.

What is your application?

The OP did say as a standby gen - so that would normally be bought and not hired. We've a 750KVa genny here for standby. And yes, it does get through it's 1000l tank fairly swiftly :-)

Definitly not something to just "order" though... needs a bit more thought than that... here is ours being "delivered"

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:-)

Darren

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