Some of us have a question, Why Capacitor is Used in Ceiling Fan or Single Phase Motor? Maybe for saving charge? Is this a real fact? Let us know about the real facts behind it. Today we will discuss why capacitor is used in ceiling fan?
If we say in simple words, when we press the switch to turn on the fan, the capacitor is used for the torque of the rotation. You should have a clear idea of induction motors to understand the use of capacitors. Because this motor is used in ceiling fan. This understanding will help you the concept of why capacitor is used in ceiling fan?
What is a Single Phase Motor?
Single Phase Motor: In simple terms, motors that run on single-phase supply are called single-phase motors. In Bangladesh, DESCO provides single-phase supply at 230 volts with a frequency of 50 cycles per second.
What is the Horsepower of Single Phase Motors?
We can already guess that single-phase motors are of smaller capacity. They are usually less than 1 horsepower, but in special cases, they can range from 1 to 10 horsepower.
Why is a Capacitor Used in a Single Phase Motor?
We know that single-phase motors mainly use AC power supply. When AC supply is provided, it creates an alternating magnetic field within the motor.
However, unlike three-phase motors, the magnetic field does not rotate at synchronous speed. This happens because the torque generated by the positive half-cycle and the torque generated by the negative half-cycle are equal and opposite. As a result, the combined torque is zero, and the motor cannot rotate.
So we will start with the work process of the induction motor. By understanding the work process it will be easy for you to understand why capacitor is used in ceiling fan?
Work Process of Induction Motor
Take a magnet bar. Then hang it in the air. Which direction it is facing? The answer is north-south. Because it wants to stay in the same direction as the magnetic field of the earth. It is a general characteristic of the magnet. Every magnet wants to align with an external magnetic field.
If we rotate the magnetic field, the magnet will also rotate with it. It’s the main process of the motor. It means the motor works with two magnetic fields. Rotating magnetic field and still magnetic field, which follows the moving magnetic field.
How Rotating Magnetic Field is Made?
- We can obviously do it by rotating the magnet. It can also be done by the electric flow. You must have heard of the electromagnet.
- We all know that, if electricity flows in a coil it creates a magnetic field.
- By giving the wire solenoid shape and flow of DC current, the created magnetic field is as same as the magnet bar’s magnetic field. Because the coil will act as a short circuit for DC current. As DC current has no up-down, the frequency is zero. So there will be no changing magnetic field.
- But it’s not rotating. There is an interesting way to create an electromagnetic field. The way is supplying 3 phase current. Because it has up-down or frequency.
- You can see three live wires in the transmission and distribution line. If the same amount of current flows through the wires there still be some difference. Current flow in each wire is 120° away from each other.
- They have no other difference except this. But this exception has brought a big advantage in motor design. When we fold this 3 phase current and because of it’s flow, there will be an acquisition magnetic field that is rotating.
- And if we put a magnet in the middle, it will follow this magnetic field and keep rotating. And this is our motors working process. Because same pole of magnetic field attracts and opposite pole distracts each other. This motor is not induction motor. It is called synchronous motor. Because it’s rotation speed is the same as rotating magnetic fields speed.
In an induction motor, there is no magnet, a loop of wire is in the middle of it. Michael Faraday has shown that, if the changeable magnetic field is used in a wire loop, current flow will be induced. This is electromagnetic induction.
Most of the house has one phase connection. Then how does the induction motor of the ceiling fan work? Or, you can say why capacitor is used in ceiling fan?
A rotating magnetic field is not created by any one-phase current flow. Because two equal but the opposite rotating magnetic field can create equal and opposite torque in the motor loop. As a result, the motor stays still.
But if you move the fan in any direction, the torque value will increase on that side. Then torque is not zero and the motor gets activated or the fan turns on. It is called the manual starting of ceiling fan.
Sometimes, if the fan doesn’t get started and you move it to any side it continues the rotation. And that’s the reason why capacitor is used in ceiling fan.
Question: Why isn’t the fan rotating even after turning the switch on?
We already know that a fan’s motor is a single-phase induction motor, and it is not self-starting, which is why a capacitor is required. If the capacitor weakens or fails for some reason, the single-phase motor cannot rotate.
The image shows the connection diagram of a single-phase motor. Additionally, if a fan suddenly stops working, other issues could be responsible. Problems in the fan’s coil can also cause the fan to stop working.
Why is a capacitor used in a fan?
Capacitors are used in fans to provide the initial torque needed to start the motor. In single-phase induction motors, such as those in ceiling fans, a capacitor creates a phase shift between the current in the main and auxiliary windings. This phase difference generates a rotating magnetic field, allowing the fan blades to start rotating and continue running smoothly.
Why is a capacitor used in a single-phase motor?
A capacitor in a single-phase motor is essential for generating the phase angle difference between the current in the main winding and the auxiliary winding. This phase shift creates a rotating magnetic field, which enables the motor to start and maintain rotation. Without the capacitor, single-phase motors cannot generate enough torque to start on their own.
Why is a capacitor used in an air conditioner?
In an air conditioner, a capacitor is used to provide the necessary power boost for starting the compressor and fan motors. The capacitor helps create the required torque for these motors to start efficiently, ensuring that the compressor can pump refrigerant and the fan can circulate air properly. It also helps maintain the system’s operational efficiency.
Why is a capacitor used in a circuit?
Capacitors are used in circuits to store and release electrical energy when needed. They smooth out fluctuations in voltage, filter noise, and can act as backup power sources for a brief period. In AC circuits, capacitors can also improve power factor by compensating for lagging current in inductive loads, improving overall circuit efficiency.
That’s all for today’s article ‘why capacitor is used in ceiling fan?’
Hope it was helpful for you to understand why capacitor is used in ceiling fan?
You can also read: Discussion about Load Break Switch
