About transformersplease explainthanks

[cartik]

I am learning about transformers, and I am really confused! Please explain what's kVA,input power,output power,and the copper losses and iron losses.can the kVA be taken as input power that's v1i1, how is kVA related to the input and output.is kVA into power factor equal to output. And how is copper power loss at full load is 4 tim es that of half load.how does the out put power become half when load is made half?? I am familiar with the basic stuff.its this kVA and load that has messed things up.

 

[cartik]

Is v1i1 equals( kVA+ p(iron loss) + p(copper loss))
Expression correct? If yes how does the book say that v1i1 equals kVA equals V2i2??
:(

 

[NascentOxygen]

how is copper power loss at full load is 4 tim es that of half load.how does the out put power become half when load is made half??

The term "load" for a transformer being shorthand for secondary current, where full load means the full rated secondary current, and half load being half of this.

Copper losses in the model are represented by the current in a resistance,
it dissipates energy as heat. 

power loss = I².R

if you consider half current, then power loss 
= (½.I)².R
= ¼.I².R ... and there you see that factor of ¼