A step-up transformer is used in a microwave oven power supply to convert the mains electrical supply to a high voltage suitable for the magnetron.
Compare the number of turns on the primary coil of a step-up transformer with the number of turns on its secondary coil.
This transformer is designed to increase the voltage from 230 V230\text{ V}230 V to 4600 V4600\text{ V}4600 V. The secondary current is 0.45 A0.45\text{ A}0.45 A.
(i) State the equation linking primary voltage, primary current, secondary voltage, and secondary current for a transformer.
(ii) Calculate the primary current in the transformer, assuming the transformer is 100%100\%100% efficient.
An engineer notices that the transformer core becomes warm during operation.
Suggest how this thermal energy generation affects the electrical input to the transformer, assuming the secondary voltage and secondary current do not change.
