KVA Rating of transformer with additive polarity (in KVA)=   
 
    1320.  
 
 Efficiency of auto transformer with additive polarity (in %)=   
 
    99.996214  
 
 KVA Rating of transformer with subtractive polarity (in KVA)=   
 
    1080.  
 
 Efficiency of auto transformer with subtractive polarity (in %)=   
 
    99.995372