3 phase generator output

[andy]

having a discussion with someone about how many amps per phase will i get out of an 80KVA, 3phase genny - and we both get different answers. i get 92.75A, he gets 160A.

my way: 80KVA x 0.8pf, 64KW, /230v = 278.26A /3 = 92.75

his way: 80KVA x0.8pf, 64KW /230v = 278.26A /1.73 = 160.84A

So, are any of these right?

 

[ricicle]

You're both wrong - 80kVA is 116A per phase @ 230/400V

Which is the maximum current the genny can provide

 

[andy]

care to explain?

 

[plugwash]

I think it depends on the situation, what I think the manufacturer is saying is that it can produce 80KVA when given a load with 0.8 power factor so if your load has a power factor of 0.8 then your limit will be what ricicle says but if your load has a power factor of 1 then it will be what you say.

Your friend is just plain wrong

 

[Pensdown]

his way: 80KVA x0.8pf, 64KW /230v = 278.26A /1.73 = 160.84A

So, are any of these right?

That's where he's gone wrong, but I think you're both wrong.....

 

[ricicle]

When looking at the kVA rating of a genny this is refering to the maximum current it can supply at rated voltage.(VA)

Thus 80000/ (1.73x400) = 116A approx per phase

Depending on the power factor of the load will depend how much of this current is doing actual work (real power - kw) and how much is contributing to reactive power (KVar)

 

[andy]

Thus 80000/ (1.73x400) = 116A approx per phase

i have no idea where my way of working it came from... been a long time since i done this in college...

 

[Pensdown]

@ Unity PF I had 115.47 but I did go the whole hog and use 1.732

Is the quoted 80kVA prime or standby power because that has a big influence on what you actually draw for any length of time.

 

[ColJack]

where does this 1.732 come from?

i thought it was x0.7... or is that to get power per phase from 3 phase KW?
nevermind, it's sqrt 3.

 

[Pensdown]

(Memory Jog) root 3?

You need some sleep

 

[andy]

Is the quoted 80kVA prime or standby power because that has a big influence on what you actually draw for any length of time.

80KVA continuous