example 4 7   
 
    first transformer   
 total full load losses 300kW 
 full load copper losses 180kW 
 energy loss due to copper losses 405900kWh/year
 energy loss due to iron losses 420000kWh/year 
 cost of energy losses Rs660720per year 
    second transformer   
 total full load losses 200kW 
 full load copper losses 110kW 
 energy loss due to copper losses 248050kWh/year
 energy loss due to iron losses 315000kWh/year 
 cost of energy losses Rs450440per yearadditional interest and depreciation due to higher cost of second transformer Rs30000 
 total yearly charges for second transformer Rs480440 per year