Problems on transformer equivalent circuit analysis.

[alexander3133]

Tests are performed on a 50Hz transformer which yield the following results:

Short circuit test: primary voltage = 40V, primary current = 10A, Power input = 20W

Open circuit test: primary = 240V, primary current = 1.2A, Power input = 70W

Determine the equivalent circuit parameters, the turns ratio and the regulation of the transformer assuming that the rated primary voltage is 240V @ 50Hz and the rated secondary current referred to the primary is 10A.

The equivalent circuit parameters is not a problem to me, the only problems was to find the turns ratio and the regulation. I was told that the turns ratio can be found in open circuit test, but how?and also the regulation.