We all might have heard that a capacitor is connected in the installation of a ceiling fan. Does the fan can run even without the installation of the capacitor? Let's have an understanding of it.
Is the capacitor the real hero?
Single phase induction motor is used in a ceiling fan for its operation. Like as shown in the figure it has starting and running winding and also a capacitor in series with the starting winding.
Generally, a single phase induction is not self starting. Suppose if there was only the rotor and the two windings, the net emf when the supply voltage is given would be just zero. Hence the magnetic field is null. And hence our fan (rotor) fails to rotate once we switch it ON. To make the rotor to rotate, a rotating magnetic field should be present. This can only be made possible if the two windings could have a phase shift of 90 degrees.
The connection of capacitor with the starting winding makes a phase shift of 90 degrees between the two windings (A and B in figure 3). This phase shift enhances the current flow. Thereby a rotating magnetic field is induced and our fan starts the rotation once we switch it ON.
