TRANSFORMER THEORY Transformers Example 2: An iron core transformer with a primary voltage of 240 volts has 250 turns in the primary and 50 turns in the secondary.   Find the secondary voltage. Solution: V_P V_S N_P N_S Next, solve for V_S. V_S N_S N_P V_P V_S 50 250 240  volts V_S 48  volts Example 3: A power transformer has a turns ratio of 1:4.  If the secondary coil has 5000 turns and secondary voltage is 60 volts, find the voltage ratio, V_P, and N_P. Solution: VR TR VR 1:4 V_P V_S VR 1:4 1 4 V_P 1 4 V_S 60 4 15  volts TR N_P N_S 1 4 N_P 1 4 N_S 5000 4 1250  turns ES-13 Page 6 Rev. 0