transformer efficency problem

[sparktobe]

the answer is 94.4% but can`t get the calcs to add up.

12 x 0.9 = 10.8

10.8 - 0.600 = 10.2

10.2 / 10.8 = 0.944

0.944 x 100 = 94.4

OR

12 x 0.9 = 10.8

10.8 + 600 = 11.4

10.8 / 11.4 = 0.947

0.947 X 100 = 94.7

andys formaula used rated kva in your question you show output kva that would accout for different answers. ?:|

 

[a1pacino]

1 A transformer is rated at 10kW but is only delivering 9.8kW. Copper losses are 0.33kW and Iron losses are 0.2kW. Calculate the efficiency of the transformer.

i get this:

9.8-0.53=9.27 op

9.8 ip

9.27/9.8x100= 94.5%

Answer off swindon massive is 90.4% but cant work out how can anyone enlighten me got 301 coming up and need to get these under manners!

cheers