Question

State one advantage of using a.c. over d.c.

Answer 1

Electric energy is generated and used is AC because it offers much advantages then DC.
Below are the advantages of AC over DC:

• AC can be generated at high voltages, but DC cannot be generated at high voltages because sparking starts at the commutator at high voltage, due to which commutator gets damaged.
• High voltages AC generators are much simpler and cheaper than DC generators of the same range. It is because in AC generators there is no commutator which is costly part and is damaged.
• Alternating current can be stepped up or stepped down with a static device called transformer. When voltages is stepped up current decreases to a small value. Small current produces less heat and can be transmitted through a thin conductor. Thus it is possible to transmit AC at high voltages. This reduces the size of conductor, transmission losses and increases transmission efficiency. At the receiving station, voltages can be stepped down to the required value by using step down transformer. This is most important reason for generating and using electrical energy as AC.
• A.C. induction motors are simplest in construction, cheaper in cot and require less maintenance whereas D.C. motors are complicated.