still need answer please

[sparkyblue1]

Am i right in thinking a 600 KVA 3 phase supply is approx 1400 amps per phase.

Read more: http://www.electriciansforums.net/e...electrical-forum/67069-kva.html#ixzz2BMgYxgmu

 

[stef]

I am sorry, maybe it is me and my old age and I haven't had my pint ... but I still get only 850A. What am I missing? Help, maths re-sit...

 

[telectrix]

867 on my abacus, using 400V and no pf corrections.

 

[sparkyblue1]

looks like my little calculator is dead cheers chaps

 

[telectrix]

it's not the calculator at fault. it's the fingers pressing the buttons. :86:

 

[sparkyblue1]

ooooooh just cos i'm getting on a bit means doesn't what don't know doin lol:stupid:

 

[ackbarthestar]

it's not the calculator at fault. it's the fingers pressing the buttons. :86:

Try it while wearing mittens !

Supply current in the conductors = 600k/(400 * 1.732) = 867A or if you like 600k/(415 * 1.732) = 835A

However, you will not be able to use all this since you will need to factor in pf

 

[Knobhead]

Be fore you all get caried away have a look at the voltage on this 500KVA unit

 

[Rockingit]

Before you all get caried away have a look at the voltage on this 500KVA unit

Go on then........ why?

 

[Knobhead]

99% of tramsformer output voltages aren't what the IEE tell you, IE 400V nor is it the fabled 415. 433V is normal.

 

[bomjac]

99% of tramsformer output voltages aren't what the IEE tell you, IE 400V nor is it the fabled 415. 433V is normal.

Which is why my house runs at 248V and blows light bulbs like nobodies business. Goddamn DNO's too lazy to drop their volts to the new values.

 

[telectrix]

now this is where a v phase unit might be of some use.

 

[bomjac]

now this is where a v phase unit might be of some use.

Maybe, but 3kW is 3kW no matter what voltage it is on, the biggest consumers in my house are the Tumble dryer, the Dishwasher, washing machine and oven. Nothing to be gained from these by voltage optimisation. Living room and dining room have 6*50W halogens on dimmers between them, all other bulbs are miniature fluorescents or LED's, so I think I shall just have to live with replacing the G9's when they blow.

 

[cantabrian9]

Which is why my house runs at 248V and blows light bulbs like nobodies business. Goddamn DNO's too lazy to drop their volts to the new values.

Bulbs are planted in the GROUND ! Lamps go in electrical fittings !!!!

 

[Engineer54]

Maybe, but 3kW is 3kW no matter what voltage it is on, the biggest consumers in my house are the Tumble dryer, the Dishwasher, washing machine and oven. Nothing to be gained from these by voltage optimisation. Living room and dining room have 6*50W halogens on dimmers between them, all other bulbs are miniature fluorescents or LED's, so I think I shall just have to live with replacing the G9's when they blow.

Now that's not quite the case at all, ...is it!!! If it was, there wouldn't be any kind of voltage optimisers. Where/how do you think they get the savings from??

now this is where a v phase unit might be of some use.

NO, those things are definitly a total waste of time and money!! lol!!!

 

[bomjac]

My point is that by far the largest source of power used is the dishwater and tumbledryer. 3kg of wet clothes takes the same amount of power to dry at 248V as it does at 230V, so there is no saving there, it will just take slightly longer at the lower volts. Likewise the dishwasher, which uses the power mainly to heat the water and dry the dishes afterwards. Again no savings to be made there.

The only obvious place for me to see savings would be on the lighting, which is not enough to justify the outlay for an optimiser.

Now on the other hand, if I was to hook up a miniature pelton turbine to the mains water at home (no water meters where I am), I wonder how much that would generate

 

[ackbarthestar]

My point is that by far the largest source of power used is the dishwater and tumbledryer. 3kg of wet clothes takes the same amount of power to dry at 248V as it does at 230V, so there is no saving there, it will just take slightly longer at the lower volts. Likewise the dishwasher, which uses the power mainly to heat the water and dry the dishes afterwards. Again no savings to be made there.

I think it is more a case of terminology.
A lower supply voltage will produce a proportionately lower power output, but to dry a fixed weight of whatever will take longer and so use the same amount of energy. Remember, your electric meter is an energy meter not a power meter so cannot record the rate of doing work only the total work achieved.
Since the timing cycle is controlled by the frequency of the supply. Your washing or dishes are less likely to be dry by the end of the timed cycle.

 

[SPARTYKUS]

Maybe, but 3kW is 3kW no matter what voltage it is on, the biggest consumers in my house are the Tumble dryer, the Dishwasher, washing machine and oven. Nothing to be gained from these by voltage optimisation. Living room and dining room have 6*50W halogens on dimmers between them, all other bulbs are miniature fluorescents or LED's, so I think I shall just have to live with replacing the G9's when they blow.

Thats a big culprit in many houses. Alot of things can be cooked in a microwave far more cheaply. Although it's hard to convert.

I have just invested in a load of 4W LED lights, to replace the 25 GU10 halogens dotted about my house. I hope it may nullify the energy price increase this year

 

[Knobhead]

Thats a big culprit in many houses. Alot of things can be cooked in a microwave far more cheaply. Although it's hard to convert.

Oh No!
Don’t start that argument please.
Another board I’m a member of the question was asked, “Is it better to heat a cupful of water in a microwave or in a kettle?”
350 posts by engineers from around the globe and we were still no wiser!
37000 post on “How to break a bath” was also a good one. It went off topic a bit.

 

[SPARTYKUS]

Oh No!
Don’t start that argument please.
Another board I’m a member of the question was asked, “Is it better to heat a cupful of water in a microwave or in a kettle?”
350 posts by engineers from around the globe and we were still no wiser!
37000 post on “How to break a bath” was also a good one. It went off topic a bit.

Okay I won't! But the heating a cup of water question is obvious