Transformer sizing in kVA
Transformer sizing in kVA
(OP)
We are currently having an discussion between engineers (mechanical) about how you calculate a transformer size in kVA from the W/m2 loading figures.
i beleive that the kVA load required is a factor of total floor area, W/m2 and divided by the power factor.
a colleague of mine states that i need to divide this figure by sq rt of 3 to take account of 3 phase vector diagrams.
another colleague states that i need to divide by 3 as there will be 3 phase currents of all equal value to line current.
i beleive that power delievered/required is not dependant on the no of phase and that 3 phase system only reduce conductor size and improve the efficiency of power delivered by not delivering zero power twice in a cycle.
Clarification please?
i beleive that the kVA load required is a factor of total floor area, W/m2 and divided by the power factor.
a colleague of mine states that i need to divide this figure by sq rt of 3 to take account of 3 phase vector diagrams.
another colleague states that i need to divide by 3 as there will be 3 phase currents of all equal value to line current.
i beleive that power delievered/required is not dependant on the no of phase and that 3 phase system only reduce conductor size and improve the efficiency of power delivered by not delivering zero power twice in a cycle.
Clarification please?






RE: Transformer sizing in kVA
However, your colleagues' recommendation for divisions are correct to get the phase currents from kVA. Divide by sq rt of 3 for the phase currents using the phase-to-phase voltages, and divide by 3 for the phase currents using phase-to-neutral voltages.
RE: Transformer sizing in kVA
total area m^2 * w/m^2 = totla W, watts.
kW = W/1000
kvA = kW/power factor ( assume p.f.=0.8)
This is the size of your transformer, in kVA.
For line current ( in each phase)=kvA/{(sqrt(3)*V*1000)
Where V is line to line voltage.
Hope this will help for planning purposes.
As always seek help of a qulalified EE for actual desingn.
RE: Transformer sizing in kVA
RE: Transformer sizing in kVA
http://www.control.com/1026178348/index_html
for calculation formulae