10/1 step down tranformer, resistance, power loss of secondary coil

whitelockben

1. The problem statement, all variables and given/known data

A 10/1 stepdown tranformer has a full load secondary current of 50A and is rated 30kVA. The copper loss at full load is 280W. The primary winding has a resistance of 0.25ohms. The core losses are 120W.

Find the resiatance of the secondary coil and the power loss in the secondary coil. Calculate the efficience at the ratedl oad when a power factor of 0.92 exists.


2. Relevant equations

Have no got a clue but during a search of the internet I found this which I am not sure is correct ....

Efficiency = Power Output
------------------------------------ x 100
Power Output Copper Loss Core Loss

3. The attempt at a solution

have no got a clue..



Hi there, I'm just hoping some one has time to post a solution to this problem and all show the working, I'm sure I would be able to work out what has been done if the working is shown..
Thanks in advance

Ben

berkeman

Well, we sure as heck do not do your homework for you here. Take a shot at using what you are given... You are given some voltages, currents, resistances, powers, etc. What is the definition of power in terms of V and I? And overall efficiency is power out divided by power in. What are the different sources of loss, and what order are they in (first, second, etc.)?