What type of magnets are used in ceiling fans?
If permanent magnets are used, then it would become a synchronous motor. The fan motor will be rotating at exactly the same speed with which the magnetic field is rotating. The whole construction of a conventional ceiling fan motor will have to be redesigned to bring in that change. And, a synchronous motor will not start automatically unlike an asynchronous motor (induction motor).
Generally Electromagnets are used in ceiling fans for generating the magnetic flux which is used to rotate the coil and hence rotates the fan wings.
When the fan is excited with the electrical energy the Electromagnets starts rotating and the direction of the rotation of fan is same as that of the direction of rotation of magnets and the magnetic flux generated in the coil will be proportional to the input applied to the motor.
Yes, we can use permanent magnets to create magnetic field. As we know that the magnetic field is produced by an electric charge in motion So, we can say that the magnetic field of the permanent magnet is a result of the electrons within the atom spinning uniformly in the same direction. But not all the permanent magnets can be used to create a magnetic field only a few of them have the ability to sustain a magnetic field.
For example, ferrite magnet. It is a type of permanent magnet and is majorly used in applications like ceiling fans, motor, refrigerator, etc. Ferrite magnet is also known as ceramic magnet. It is made by mixing a large proportion of iron(iii) oxide with a small proportion of any metallic element (one or more).
Electromagnets are used for the ceiling fan. Ceiling fan having DC motor, the current passes through a series of magnets with opposite polarity. The resistance between the magnets creates a torque which powers the rotor.
Genarally, electromagnets are used to make magnetic field in conventional ceiling fan motors. It would be more apt to say a 'rotating magnetic field'. The poles change alternately to north and south at the supply frequency. The developed rotating magnetic field will be rotating at synchronous speed.