Construction and working principle of Ceiling fan

Do you Know? A ceiling fan is a vital household item used all over the world, and it is also an interesting engineering topic to discuss. 

As an electrical engineer, I recommend every person to know about the working principle of a ceiling fan, which will pique their interest in learning about the electrical motor. 

The working principle of the ceiling fan outlined here applies to all ceiling fan brands, including Bajaj, Orient, and Khaitan makes. 

This article discusses

1. What is a ceiling Fan?
2. Construction and working principle of the ceiling fans, 
3. What are the major parts of ceiling fans? and 
4. The circuit diagram of a ceiling fan. 
5. Why Capacitor is required for ceiling fan.

What is a Ceiling fan?

The term "ceiling fan" refers to a rotatory electrical device mounted on the ceiling vertically, providing continuous airflow that can be felt on our skin.

This ceiling fan rotates and distributes air throughout the room in all directions improving comfort during hot wheather.

In general, an energy-efficient ceiling fan uses less power, but they are more expensive costs. 

A typical local ceiling fan consumes a lot of power, ranging from 45 to 70 watts.

Did you know? (ceiling fan direction)

Ceiling fans in India rotate anticlockwise, while ceiling fans in Australia rotate clockwise. Anticlockwise rotation is for hot weather and clockwise direction for cold weather. Depending on usage the ceiling fans are manufactured.

Traditional ceiling fans have been given new designs and structures thanks to modern technology. e.g. superfan, Anderson enclosed fan with light. Superfan uses a brushless DC motor (BLDC) and it is remotely operated.

You can also skip directly to the topic "how ceiling fans work?"  on down.

Ceiling fan motor

What if your neighbors ask some questions about the ceiling fan's motor? 

The ceiling fan's motor is a single-phase induction motor, but due to the following factor, it has a variety of names.

We have all heard of single-phase induction motors and their various types. The ceiling fan is also rotated by a single-phase induction motor. 

The ceiling fan requires a capacitor because the motor is not self-starting. As a result, the motor is referred to as a capacitor split-phase starting motor.

Construction of single-phase induction motor

A single-phase induction motor typically has two windings: one for starting and the other for running.

Other names

Because of the capacitor in the single-phase induction motor of a ceiling fan, it is also known as a "capacitor split-phase motor"  or capacitor motor.

Capacitor split-phase motor is also one type of induction motor consists of main and auxiliary winding.

The capacitor split motor is also called a split-phase starting motor. 

Ceiling fan circuit diagram

Because the circuit of the capacitor split-phase has only four basic elements, a ceiling fan circuit diagram is simple to understand. As a result, the assembly of a ceiling fan is simple. The ceiling fan circuit diagram is shown below.

The circuit diagram of the ceiling fan has these three important components

1. Main Winding
2. Auxiliary winding 
3. Capacitor or condenser 
4. Rotor

Ceiling Fan Working Principle

The ceiling fan's operation is based on the law of electromagnetic induction. The ceiling fan's induction motor converts electrical energy into mechanical energy. The most of the ceiling fan motor requires a 250v single-phase alternating current supply but this may vary depending on specific model.

A single phase induction motor initially generate a pulsating magnetic field in the winding which does not lead to self starting rotation. To overcome this limitation, the motor requires a capacitor to make angle phase differences creating a rotating magnetic field.

A rotating magnetic field is the essential for the motor operation.

Pulsating magnetic field - The magnetic field builds in one direction, reaches the maximum, becomes zero, then reverse direction reaches another maximum, becomes zero again. The same process continues to repeat in a cyclic manner.

Characteristics of current and voltage for rotating force

Running winding requires a leading current (current leads voltage) to create torque (rotating force) on the rotor.  This is accomplished by permanently connecting the start and run type capacitor to the auxiliary winding during start and run conditions.

The series capacitor provides a 90 ° phase shift to the current and voltage. Due to variation in the phase angle of current and voltage the changing magnetic field creates torque in the rotor. The torque in the wind moves the rotor from one pole to the next pole.

The mechanical force of the motor efficiently utilizes the law of aerodynamic with the help of blades on a ceiling fan which is attached to the housing of the rotor. 

A concept related to the working principle of the ceiling fan are:

Aerodynamic behind the airflow

The air moves downward as the blades rotate anticlockwise. When the fan blade rotates, the curvature of the blade collides with the air particles and pushes them downward.

Speed and Power consumption

The motor's speed determines the requirement of power. The speed of the ceiling fan can be controlled by a regulator.

The voltage can be adjusted with the help of a regulator.

Final steady-state speed

When full current flows into the winding of the ceiling fan, the steady-state speed of the ceiling fan motor can be attained.

The formula for calculating the final steady speed of the fan  

N= 120* f/P

P= No of poles of the stator winding

f=Frequency of the supply

N=steady speed

Ceiling Fan Parts and Components

Here I am going to classify the ceiling fan parts into two groups, for better understanding.

1. Exterior component
2. Interior component

Exterior components

The major components of a ceiling fan are its exterior components. The mechanical strength of a ceiling fan is provided by its external components. We can see the component with our own eyes. Its exterior elements are.

1. Mounting bracket.
2. Top canopy and down canopy 
3. A shaft or connecting rod
4. Blades and Bracket fitting
5. The top cover and bottom cover housing of the motor

Mounting bracket

The mounting bracket functions as a holding arm, holding the ceiling fan vertically downward.

Ceiling fan blades

The ceiling fan should have 3-4 blades and an angle between each blade should be correctly maintained according to the standards (IEC or any other national standards).

The ceiling fan blades are designed in accordance with aerodynamic law because they create airflow when the ceiling fan is in motion. When purchasing a blade, it is important to consider the pitch, shape, and size. A slight downward curvature should be designed into the blade.

The angle between the blades is defined as blade pitch.

Interior components

The interior components can be found within the outermost structure. The ceiling fan's interior components are

1. Shaft
2. Stator and its winding
3. Rotor
4. Capacitor or condenser
5. Conducting wires

Ceiling fan internal wiring diagram

A shaft of the ceiling fan

A ceiling fan shaft is a vertical down rod that supports and holds the stator-winding of a single-phase induction motor. The shaft should be 2 to 10 inches long.

The shaft will eventually reach the stator's center. Because it houses the stator, it is a non-rotatable component of the ceiling fan.

Half of the vertical rod is visible to the eyes and the remaining parts are considered interior parts. 

Stator and winding of the ceiling fan

The ceiling fan's stator is made of thin laminated sheet metal mounted in a cast-iron frame. For the winding of the coil, the stator has slots with parallel teeth. On the slots and teeth, the two windings are wounded on the same stator. Copper or aluminum is used to make the winding coils. The majority of the company's fan windings are made of copper.

How do you determine starting and running winding of a ceiling fan?

Starting and running winding wire in a ceiling fan can be easily identified by testing the resistance value of the winding wire.

Starting wire will always have a higher resistance value and running winding wire will always have a lower resistance value.

The stator winding of the ceiling fan

On a stator, there are two types of winding: auxiliary winding and main winding. It is also known as starting winding and running winding. The main winding is wound on teeth, while the auxiliary winding is wound on slots.

Ceiling fan's Rotor

The ceiling fan's rotor is the rotating component that revolves around the stator. It appears to be the outermost shell of a stator. It also seems to be around the steel bar. Small air gaps remain between the stator and the rotor, which aids in free rotation or running.

Ceiling fan's Capacitor

The non-polarized electrolytic capacitor is used in the ceiling fan. It is capable to produce reactive power (Var) to start the rotor of a ceiling fan. Simply it provides the starting torque. 

The capacitor is connected in series to the auxiliary winding for producing mechanical force between stator and rotor by creating a leading current which means current leads the voltage. The capacitance of the ceiling fan capacitor is 4 to 6 microfarad.

Conducting wire of the ceiling fan

A conducting wire is made up of copper. A ceiling fan has two conducting wires phase wire and a neutral wire. A 240 v AC supply flow through this conducting wire. Phase wire is connected with running winding and the neutral winding is connected to the auxiliary winding.

Conclusion

Ceiling fans from popular brands such as Havells, Orient, Crompton Greaves, Bajaj, and Usha are available in India. When purchasing ceiling fans, we must consider the advantages and disadvantages of each brand or model. It is necessary to inspect the ceiling fan's motor efficiency and air delivery.

 Budget: The price of a popular brand ceiling fan can vary depending on its size and features. The majority of ceiling fans are priced between Rs. 1100 and Rs. 6000.

Common things on the ceiling fan

1. All brands should pass the Bureau of Indian Standards (BIS) test.
2. The motor should have a high efficiency of operation.
3. Long Life condition
4. Pitches of the blades should be good

What company is best for ceiling fans?