COMILLA UNIVERSITY

TERM PAPER ON ELECTRIC FAN

TERM PAPER NO: 01

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INDEX OF ELECTRIC FAN PAGE NO:

1.INTRODUCTION

1

2.LITERATURE REVIEW

History 2

Types of fans 4

Axial-flow fans 5

Table Fan 5

Ceiling fan 6

Computer cooling fan 6

Variable Pitch Fan 6

OTHER TYPES OF FAN 7

Electric Attic Fan 9

Limits AC Needs 9

Damage 10

PROCEDURE Fan drive methods 10

PROCEDURE OF FAN 10

Ceiling Fans Through out the Age

11

4. RESULTS OF FAN

ADVANTAGE: 15

Ceiling Fans benefit the home 16

Cheap 17

Ceiling fan is a common household item

17

5.DISCUSSION 18

6. CONCLUSION 20

7.BIBLIOGRAPHY 21

ELECTRIC FAN

INTRODUCTION:Electric fans are used to regulate interior temperatures. People commonly use them during hot and humid summer days to increase air movement throughout a home. Some electric fans are movable and can be put on a desk or on the floor. Larger models are permanently installed on the ceiling. Electric ceiling fans are sometimes used in the winter to circulate warmer air back down from the ceiling.

Fig: Electric fan.

Electric fans made their first appearance in the 1880s. These early fans were made primarily of brass. Over the ensuing decades, fans were constructed out of a large number of materials, including steel, copper and aluminum. In the 21st century, most domestic fans are made out of plastic. Schuler Wheeler invented the electric fan in 1886.

"Wheeler (1860-1923) figured out how to apply the fledgling science of electricity to make a fan turn. Drawing on the work of Thomas Edison and Nicola Tesla, Wheeler invented a desktop fan consisting of two blades-unshielded by any sort of protective cage-powered by an electric motor. The fan was marketed by the Crocker & Curtis Electric Motor Co’’.

‘‘... further development of the electric fan fell to Philip H. Diehl, a German immigrant who'd lost everything in the 1871 Chicago fire’’ .

LITERATURE REVIEW:

History:

The Industrial Revolution in the late 19th century introduced belt-driven fans powered by factory water wheels. Attaching wooden or metal blades to shafts overhead that were used to drive the machinery, the first industrial fans were developed. One of the first workable mechanical fans was built by Omar in 1832. He called his invention, a kind of a centrifugal fan, an "air pump." Centrifugal fans were The Industrial Revolution in the late 19th century introduced belt-driven fans powered successfully tested inside coal mines and factories in 1832–1834. When Thomas Edison and Nicola Tesla introduced electrical power in the late 19th and early 20th centuries for the public, the personal electrical fan was introduced. Between the years 1882 and 1886, New Orleans resident Schuyler Wheeler invented the first electric fan.[2] It was commercially marketed by the American firm Crocker & Curtis electric motor company. In 1882, Philip Diehl introduced the electric ceiling fan. Heat-convection fans fueled by alcohol, oil, or kerosene were common around the turn of the 20th century.

The first American fans were made from around the late 1890s to the early 1920s, when domestic electric fans were first sold in America. [3]

They had brass [3] blades, many of them also had brass cages, and though they were built very well internally, they were far from finger safe, as the cage openings were often so big that one could put an entire hand or arm through it. Many children had hands and fingers severely injured by those fans.

In the 1920s, industrial advances allowed steel to be mass produced in different shapes, bringing fan prices down and allowing more homeowners to afford them. In the 1930s, the first art deco fan (the "swan fan") was designed. In the 1950s, fans were manufactured in colors that were bright and eye c. The Central air conditioning in the 1960s caused many companies to discontinue production of fans.[3] In the 1970s, Victorian-style ceiling fans became popular.

In 1998, Walter K. Boyd invented the HVLS ceiling fan. A lifelong inventor, Boyd was charged with developing a system to cool dairy cattle. Dairy cattle, when overheated, decrease milk production. Using the laws of physics and airflow, Boyd developed a fan that incorporated 10 aluminum blades and was 8-feet in diameter. Unlike traditional ceiling fans that move quickly, this large fan moved slowly. Due to its diameter, the fan moved a large column of air down and out 360 degrees and continuously mixed fresh air with the stale air inside the barn. It also cooled the inside of the barn without causing the dairy cattle undue stress or kicking up dust.

After much testing, Boyd discovered HVLS fan technology to be energy efficient as it cost less to run one HVLS fan than it did to run 50 small high-speed fans. Due to the skyrocketing costs of energy, HVLS commercial ceiling fans are used today to supplement HVAC systems in industrial and commercial settings, including warehouses, manufacturing facilities and malls, as HVLS fans help lower heating and cooling costs.[4]

The basic design of electric air fans has not changed significantly since their beginning in 1890.[3] Coanda effect bladeless fans introduced in the early twenty first century had not as of 2012 become a significant proportion of fans in use. In prosperous regions with a hot climate electric fans for personal comfort had been largely replaced by air conditioners.

Types of fans:

Mechanical revolving blade fans are made in a wide range of designs. In a home you can find fans that can be put on the floor or a table, or hung from the ceiling, or are built into a window, wall, roof, chimney, etc. They can be found in electronic systems such as computers where they cool the circuits inside, and in appliances such as hair dryers and space heaters. They are also used for moving air in air-conditioning systems, and in automotive engines, where they are driven by belts or by direct motor. Fans used for comfort create a wind chill, but do not lower temperatures directly. Fans used to cool electrical equipment or in

engines or other machines do cool the equipment directly by forcing hot air into the cooler environment outside of the machine.

There are three main types of fans used for moving air, axial, centrifugal (also called radial) and cross flow (also called tangential)

Decorative tabletop figurine fans:

Tabletop electric fan does not have to look like an unattractive appliance. It does not have to be the utilitarian device with the caged blades that comes out of hiding in the heat of summer. A cool breeze can be hot stuff.

Here is a collection of whimsical Deco Breeze figurine fans which are functional as well as decorative. Each artistically sculpted ironwork fan is made of top quality 30-watt copper-spun motor which will be turning

heads. Will it be this Cheshire Cat with the mischievous grin, or a Woody station wagon, or Birds of Paradise floral arrangement with cooling effects? There are so many to choose from in this fan - static gallery.

Axial-flow fans:

The axial-flow fans have blades that force air to move parallel to the shaft about which the blades rotate. Axial fans blow air along the axis of the fan, linearly, hence their name. This type of fan is used in a wide variety of applications, ranging from small cooling fans for electronics to the giant fans used in wind tunnels. Axial flow fans are applied for air conditioning and industrial process applications. Standard axial flow fans have diameters from 300-400 mm or 1800 to 2000 mm and work under pressures up to 800 Pa.

Examples of axial fans are:

Table Fan: Basic elements of a typical table fan include the fan blade, base, armature and lead wires, motor, blade guard, motor housing, oscillator gearbox, and oscillator shaft. The oscillator is a mechanism that moves the fan from side to side. The axle comes out on both ends of the motor, one end of the axle is attached to the blade and the other is attached to the oscillator gearbox. The motor case joins to the gearbox to contain the rotor and stator weighted base.

Fig: Table fan

Ceiling fan: A fan suspended from the ceiling of a room is a ceiling fan. Ceiling fans can be found in both residential and industrial/commercial settings.

Fig: Ceiling fan.

In automobiles, a mechanical fan provides engine cooling and prevents the engine from overheating by blowing or sucking air through a coolant-filled radiator. It can be driven with a belt and pulley off the engine's crankshaft or an electric fan switched on or off by a thermostatic switch.

Computer cooling fan:

Variable Pitch Fan:

A variable-pitch fan is used where precise control of static pressure within supply ducts is required. The blades are arranged to rotate upon a control-pitch hub. The fan wheel will spin at a constant speed. As the hub moves toward the rotor, the blades increase their angle of attack and an increase in flow results.

OTHER TYPES OF FAN :

There are many types of electric fans, including portable or personal-sized fans, industrial-strength high-powered fans, and electric box fans. Oscillating electric fans circulate air by revolving fan blades as they spin. Some electric fans are dual powered, meaning they can run on batteries as well as electrical power.

Fig: Box fan.

Box fans are generally less expensive than other styles of electric fans. They are square, similar to the appearance of a box. Some of these electric fans are constructed of metal, while others have plastic blades.

An industrial-strength, high-velocity fan is a good choice for those who wish to cool a large area or room. Some of these are free standing and feature wheels on casters. This enables the fan to be moved about.

The high-velocity fan may be constructed of coated metal, including the fan blades. This type of fan typically features multiple speeds. The interior motor is encased inside the metal housing. Many people use these fans in garages, offices, and warehouses, but they are also suitable for

very large rooms. The powerful motors of these electric fans will circulate air more efficiently than a standard fan.

Oscillating electric fans may have a floor stand or be made to sit on a table top. These types of fans allow air circulation from all directions, as the head of the fan oscillates. The fan head will generally be adjustable for various angling. The floor-standing models may have various height adjustments.

Fig: 75 air supply fan blade.

Fig: Household window fan.

Electric Attic Fan:

Having an electric fan in the attic can help with energy savings throughout the home because the attic temperatures affect the entire house. Electric fans come with many advantages as wellas disadvantages that should be considered prior to installation.

New DesignsThe Modern Fan Company has introduced three new ceiling fans: Pensi (designed by Jorge Pensi), Velo and Velo Hugger. Each adds new features to our expanding collection. The Pensi and Velo fans each incorporate new, contoured blade designs delivering increased efficiency and an attractive appearance.

pensi velovelo

huggerConsciously Cool

Modern Fans can keep you comfortable while helping to reduce energy consumption in several ways. Like a nice breeze on a warm day, moving air offers recognizable relief from heat and humidity (scientists have a term for what's happening on your skin-“evaporative cooling.”). This “cooling” effect allows for upward adjustment of your AC thermostat by as much as 8 degrees, resulting in up to 40% reduction in power consumption. In many cases, air conditioning can be turned off entirely, with a Modern Fan using less electricity than a standard light bulb.

Additional reductions and savings are gained in cooler seasons when Modern Fans are used to re-circulate heated air that would otherwise remain trapped or stratified near the ceiling. Furthermore, we offer longlife, color-balanced compact fluorescent lamp (CFL) options with all but one of our products. CFLs use only 25% of the energy consumed by equivalent incandescent or halogen lamps.

Limits AC Needs

Using an electric attic fan can prevent the use of an air conditioner within a house—assuming that the outside temperature is below 82 degrees. Electric fans work to draw heat out of houses and therefore can substitute for the air conditioner.

What's important to note is that the fan is only used when the engine is idling, or the car is creeping along at low speed (less then 20 MPH). If the car is stationary or creeping, there is not enough natural airflow through the red to provide adequate cooling. Thus, the necessity of a fan .

Lower Energy Efficiency:

If the sealing is not installed correctly between the fan and the home, attic fans will lower energy efficiency by not working properly.

Damage:

Attic fans are mounted on roofs, which makes them more prone to

damage. This is more often the case in areas prone to harsh weather.

Procedure

Fan drive methods:

Standalone fans are usually powered by electric motors, often attached directly to the motor's output with no gears or belts. The motor is either hidden in the fan's center hub or extends behind it. For big industrial fans, three-phase asynchronous motors are commonly used, placed near the fan and driving it through a belt and pulleys. Smaller fans are often powered by, or brushed or brushless DC motors. AC-powered fans usually uses main voltage , while DC-powered fans use low voltage, typically 24, 12, or 5 V. Cooling fans for computer equipment always use brushless DC motors, which generate much less electromagnetic interference than other types.

In machines with a rotating part, the fan is often connected to it rather than being powered separately. This is commonly seen in motor vehicles with internal combustion engines, where the fan is connected to the drive shaft directly or through a belt and pulleys.

A common configuration is a dual-shaft motor, where one end of the shaft drives a mechanism, while the other has a fan mounted on it to cool the motor itself. Window air conditioners commonly use a dual-shaft fan to operate separate blowers for the interior and exterior parts of the device.

Where electrical power or rotating parts are not available, fans may be drive by other methods. High-pressure gases such as steam can be used to drive a small turbine, and high-pressure liquids can be used to drive a wheel, which can provide the rotational drive for a fan.

Large, slow-moving energy sources such as a flowing river can also power a fan using a water wheel and a train of gears or pulleys.

Ceiling Fans Through out the Age :

Ceiling fans cool because of wind chill. Wind chill is the fact that moving air hitting your skin feels cooler than stale air. The first humans to ever create artificial wind chill via a tool were the ancient Assyrian and Egyptian royalty, who employed servants to wave large leaves over them to cool them on hot days.

Hand held fans have been around for over 2,000 years. The Japanese folding fan has been around for almost 1,400 years. During the Middle Ages hand held fans become very popular among Europeans. During the 1700s there were over 150 master hand held fan makes in Paris, France alone. Hand held fans were quite popular and fashionable during this time period, especially among upper class women.

Also, during the 1700s inventors were wrestling with the idea of creating mechanically driven personal fans. Many of these one off inventions are enormously expensive today and paved the way for modern fans. Mechanical ceiling fans were first successfully implemented in factories during the industrial revolution. Workers suffering from heat exhaustion got the idea of attaching metal or wooden blades to whirl shafts overhead that were used to drive machinery. During the 1860s and 1870s factories in the United States used water-powered turbines to drive belts that could spin multiple two blade ceiling fans. These turbine powered belt driven ceiling fans become popular in many high-class restaurants and office buildings.

Philip Diehl is considered the father of the modern electric fan. Diehl was the head of the company, Messrs, Diehl and Company, one of the larger companies in the early electronics industry. One of Diehl’s greatest inventions was the first electric motor suitable for use within Singer sewing machines. A derivation of this motor was eventually used within the first electric ceiling fan.

Amid much publicity, in 1882 Diehl introduced the very first electric ceiling fan. The first electric ceiling fan had two bubble blades that were driven by a self-contained electric motor that was an adaptation of Diehl’s sewing machine motor. Toward the later 1880s and early 1890s the Diehl electric ceiling fan became a big hit throughout America.

Diehl refined his electric ceiling fan over time, making smaller motors and even adding electric lights. Eventually Diehl introduced the electronic ceiling fan, which was a combination chandelier and ceiling fan. By the early 1900s the electric ceiling fan was prolific and in the homes and businesses of individuals all over the world. By the 1920s ceiling fans were utilized by almost every American consumer services oriented business, such as restaurants, in the country.

In the 1970s, during America’s energy crisis, ceiling fans again become widely popular because of how little energy they consume relative to other cooling systems. One of today’s foremost ceiling fan manufacturers, the Casablanca Fan Company, was founded in 1974. Around the same time other popular ceiling fan companies, such as Hunter Fan Company and Emerson Fans, came into prominence. History has made the case for ceiling fans as a low energy consuming method of increasing airflow and cooling in a variety of environments. Today, billions of ceiling fans are used around the world to make your and my world a little cooler.

 Because of its beauty and appeal, you should not be surprised at how Casablanca fans are priced in the market. Some of them can be collector items. They are not inexpensive.

Why inexpensive ceiling fans may be noisy

Inexpensive fans generally lack proper noise-reducing components such as isolation rings and rubber cushions between metal parts. These special noise silencers help stop the transference of noise through the fan to the ceiling where it is magnified. Inexpensive fans usually do not have these components because they add extra costs to manufacturing. Noise is generated because the fan in general is poorly engineered and manufactured using short-cuts

The motor is important

For a fan to operate efficiently and effectively, the motor size must be engineered to match the blade pitch and blade length. Inexpensive fans may have inadequate size motors which can cause over-heating and motor burn-out. In many instances, lower quality fans may not have enough blade pitch to effectively move air.

The greater the blade pitch, the more movement of air... but remember, the greater the pitch, the greater the need for a larger motor!

Ceiling Fan Flow

In the summer it is typical to have the ceiling fan blow down to circulate the most air flow in the room. Also the air flow directly on you is cooling. I winter it is better to have the flow up to take the warm air on the ceiling and move it throughout the room. You also don't want the air flow directly on you -- you want to stay warm, not cool.

Why does a table fan rotate clockwise and a ceiling fan anti-clockwiseThere should be a switch on your ceiling fan that allows it to rotate in either direction. The reason for this switch is so that the direction of rotation can be changed along with the seasons.

The ceiling fan should blow down in the summer time and draw upwards in the winter time. By drawing air upwards in the winter time is circulates the warm air which accumulates in the ceiling area and moves it down the walls to the floor level

RESULTS OF FAN:

ADVANTAGE : The primary benefits ceiling fans give is the benefit in air circulation. Ceiling fans are proven to make people in a room feel four degrees cooler in the summer. If installed over a dining table, the ceiling fan can help keep flying insects away during meals. In the winter time, a ceiling fan circulating the air helps to distribute warmth coming from a space heater or heating stove around the neighboring rooms of the house. Modern home builders are accustomed to installing air conditioners to take care of their house's overall summer cooling needs. But the electrical needs required and the monthly cost can be prohibitive.

Ceiling fans provide alternative for the air conditioner, when the heat is not too bad, and they are less costly in electricity. The electricity consumed by operating a ceiling fan is pennies per month when compared to dollars a month for a modern efficient air conditioner.

 During summer, the ceiling fan is run counter-clockwise to provide cooler breeze. If your fan features a switch for reversing the rotation direction, then it can run in the clockwise direction for the winter months. By reversing the direction, air is drawn up to the ceiling instead of down to the floor during the summer.

 The ceiling fan has truly revolved since it was invented in 1886. If the Hunters were still alive, they would certainly be awed at how their invention has evolved.

Ceiling Fans benefit the home: Ceiling fans are popular ceiling fixtures not just in the households in tropical countries. Ceiling fans are similar in function to any other electric fans. Of course, their main use is to generate air movement to improve the ventilation of a room.

 Ceiling fans are electric fans that are hanging over the ceiling. Some people prefer to install ceiling fans rather than put traditional electric fans in the room because of the significant amount of space that is saved, as well as being a permanent fixture that's out of the way.

During the great depression when people didn’t have the luxury of paying for a cooler environment, along with many other industries, the ceiling fan industry suffered immensely. All the way through world war two, the ceiling fan was not very popular in America. Throughout the rest of the world, the ceiling fan was becoming immensely popular in warmer climates.

In the 1970s, during America’s energy crisis, ceiling fans again become widely popular because of how little energy they consume relative to other cooling systems. One of today’s foremost ceiling fan manufacturers, the Casablanca Fan Company, was founded in 1974. Around the same time other popular ceiling fan companies, such as Hunter Fan Company and Emerson Fans, came into prominence.

History has made the case for ceiling fans as a low energy consuming method of increasing airflow and cooling in a variety of environments. Today, billions of ceiling fans are used around the world to make your and my world a little cooler.

Cheap:

Electric fans are very cheap to operate. They require very few watts of energy and therefore are cost-effective—even in summer months.

Ceiling fan is a common household item that requi r es wiring.

Wiring an electric fan for your home requires patience, caution and research. Electrical wiring is dangerous and must be handled carefully. Most fans found in an average home use single -phase motors that either operate at 120 or 220 volts. Before wiring one of these electric fans, have all of your manufacturer's documentation, such as installation and wiring instructions, within easy reach. These documents should be studied and understood before beginning any wiring. They also provide warnings and safety precautions that should be followed.

DISCUSSION:

There should be a switch on your ceiling fan that allows it to rotate in either direction. The reason for this switch is so that the direction of rotation can be changed along with the seasons.

The ceiling fan should blow down in the summer time and draw upwards in the winter time. By drawing air upwards in the winter time is circulates the warm air which accumulates in the ceiling area and moves it down the walls to the floor level.

Maintaining your ceiling fans

An anti-static agent can be used, but no cleaning agents which can damage the finish.

An occasional coat of furniture polish may be applied to the wood protection. Polish will also enhance the wood.

Never saturate a cloth with water to clean your ceiling fan. Water introduces the possibility of electrical shock and blade warpage. Always be certain the fan control is in the off position before attempting to clean

Electric fans are an often discussed modification on the various RX-7 forums. Unfortunately, it seems that there is also a lot of inaccurate information surrounding the "e-fan" and how it should be installed. . You can install the largest fan possibly and move as much air through the radiator as you want yet the temperature of the engine will remain the same as set by the thermostat. It is very important to realize that it is the thermostat that regulates the temperature of the engine, and not the fan.

Many people also seem to believe that an electric fan will cure their "at speed" overheating problems. Recall that the fan is not even used when at speed, as the natural flow of the air through the radiator is more then

enough (much more then a fan, in fact) to keep the car cool. . Electric fans draw quite a lot of current. Most pull surges of 35A or more to start up than run at 8A-10A.

There is also an in efficiency in the whole system. We are converting mechanical energy, to electrical energy, to mechanical again to run the fan. This very inefficient, much less then just driving the fan directly via the mechanical energy of the rotating shaft.

Fans are made to save space. These feature a tall and thin design, and most feature an oscillating mode. Many also have an optional remote control, allowing the user to operate the unit from across the room. The slim structure of the fan makes it a good choice for busy areas.

CONCLUSION:

After discussing whole we can say that, fans produce air flows with high volume and low pressure, as opposed to compressors which produce high pressures at a comparatively low volume.

Differences in air temperature will affect the density of air and can be used to induce air circulation through the mere act of heating or cooling an air mass. This effect is so subtle and works at such low air pressures that it does not appear to fit the definition of a fan technology.

However, prior to the development of electricity, convective airflow was the primary method of inducing airflow in living spaces.

Older houses from before electrification often had open duct grilles leading from the ceiling of a lower level to the floor of an upper level, to allow convective airflow to slowly rise up the building from one floor to the next.

However, people uses fan during hot or summer days which make their life more comfortable. The primary purpose of domestic fans is to increase comfort during hot and sticky weather.

BIBLIOGRAPHY

1. www.hse.gov.uk 2. http://www.modernfaneu.com

3. http://www.wonderquest.com

4. http://www.hansenwholesale.com

5. http://wiki.answers.com

6. http://wiki.answers.com