An industrial step-up transformer is used in a neon sign power supply to convert the mains electrical supply to a higher voltage.
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 4.6 kV4.6\text{ kV}4.6 kV. The secondary current is 15 mA15\text{ mA}15 mA.
(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 casing becomes warm during operation.
Suggest how this affects the electrical input to the transformer, assuming the secondary voltage and secondary current do not change.