Today topic of our post is: why are two windings used inside the fan? This topic is very important for the people related to electrical, because today’s question is very basic, and it is very important for electrical interview. Whenever it comes to our motor, the most commonly used motor is our ceiling fan. So now the question related to this comes that why are there two windings inside our ceiling fan?
Which winding is inside the fan ?
As you can see in the photo below that the first winding is done outside and our second winding is done inside.
First of all, when we talk about the winding of our ceiling fan, then outside winding is called main winding. Main winding’s work is very important in motor, And the inner winding is our auxiliary winding, sometimes we also call it starting winding. And we also call main winding as running winding. So now we understand both the windings working one by one.
What is working of main winding in motor ?
As we have seen that our inner winding is auxiliary winding and outer winding is main winding. So as their name suggests their work. Main winding, name suggest that this is our main winding. It start motor.
But the second winding is auxiliary, it help in the start of motor, which means that it is just helping the motor to start, but our main winding does the work of run the motor.
Now the question comes that why are two windings done inside a 1 phase motor. Then you just need to know that when we have done winding in the celling fan or any other fan and we connect this winding with the phase and neutral then rotor of the motor feel torque( rotor is part of motor which rotate).
now in this case when we have add only main winding with phase and neural. Then rotor feel an bidirectional torque.
Simple mean of torque is push. Means some kind of pressure. When current flows inside our winding, a magnetic field is generated inside it. And this magnetic field works to push our motor. Means in technical language, give torque on our rotor. But the torque that we will get right now is our bidirectional. All you have to remember about this question is that in a 1phase motor, if only one main winding is used, then bidirectional torque is applied on it.
Bidirectional torque means friends that the torque on our rotor will be applied upwards and downwards on both sides. Meaning that our motor will want to rotate once down and once up. Meaning that sometimes there will be a push up, sometimes there will be a push down.
So what will happen due to such a push that our motor will not be able to rotate. Because the bidirectional torque it exerts inside the single phase motor is our 50Hz frequency. That is, within 10 milliseconds it gets pushed again and again. Meaning that there is a push upwards for 10 milliseconds and downwards for 10 milliseconds.
So due to this the motor which we have keeps vibrating in one place. So now the question comes that why 2 windings are done.
Friends, the reason for installing 2 windings is simple that we put another winding on the outer winding, which we call auxiliary winding. It has another name that is starting winding because it helps in starting the motor.
Friends, with this second winding, we also put a capacitor in the series. You must have seen the ceiling fan having a capacitor of 2.5 mF. in 1 phase. our motor was not rotating, now what we did is that we installed another winding called auxiliary winding.
So what happened by doing this that whenever we gave a single phase supply to our motor, then by doing this it happened that the torque that is being applied to our motor is not bidirectional. In this case our torque will be unidirectional. That is, the force on the motor will be in only one direction.
So friends, if this question asked in interview then you have to say two lines that not only our selling fan but all our 1 phase motors, they have 2 windings.
We do this because when we have only one winding and we supply neutral and phase to it, then bidirectional torque is applied in it. Due to which the motor does not rotate and vibrate on one place. So for this we do another winding which is called auxiliary winding and connect a capacitor in the series of this winding and by doing this the torque which is applied is unidirectional i.e. the torque is applied in the same direction so that The motor starts spinning.
what is difference between main winding and auxiliary winding ?
- main winding is used to produce flux, where auxiliary winding helps in start motor.
- more turns in coil are used in main winding as compare to the auxiliary winding.
- size of turns is big in main winding as compare to auxiliary winding.
- Auxiliary winding lead to main winding with 90′.
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