Question

Why is the capacitor used in a fan?

Answer 1

Hint:A capacitor stores electric charge. It is a little bit like a battery except the fact that it stores energy in a different way. A capacitor cannot store as much energy as a battery. Although it can charge and release its energy much faster. Therefore, now, we shall look into the usage of a capacitor in an electrical fan.

Complete answer:
The circuital arrangement of electrical fan have one switch, one starting winding and one running winding and stator, one capacitor serially connected with starting winding and one rotor.

Let us first consider the electrical fan circuital arrangement without a capacitor.

This is the circuital engagement of an electrical fan without a capacitor. When the switch is closed 230V A.C. is entering into the circuit and the same phase is entering into the starting winding and running winding. When we have the same phase for two-windings, no magnetic rotation is created. Hence, the rotor will not get rotated for this arrangement of fan without capacitor.
In order to create magnetic rotation, we have to give two different phases for each winding but as we have single phase connection in homes, we cannot make two phases to give.
Thus, to overcome this problem, a capacitor is used. A capacitor is serially connected with starting winding in the circuital arrangement of an electrical fan.
Now when the switch is closed, 230V AC is entering into the circuit. Same phase is entering into the running winding and capacitor. However, the capacitor shifts the phase of the current and thus, a shifted phase AC comes out of the capacitor and goes to the starting winding while the applied phase AC is in the starting winding.
Due to the two different phases in each winding, magnetic rotation is created and thus the rotor starts rotating.
Therefore, a capacitor is used in a fan to create a phase difference in the current of the two windings which in turn creates a magnetic flux and makes the rotor of the fan rotate.

Note:
We should be very careful with capacitors as we know that the capacitors store energy and can hold high voltage values for a long time even when disconnected from a circuit. In order to check the voltage of a capacitor, we can make use of a multimeter device and switch to DC voltage.