A ceiling fan is a mechanical fan, usually electrically powered, suspended from the ceiling of the room, using a rotating paddle mounted in a hub to drain the air.
Ceiling fans usually rotate more slowly than other circulating fan types, such as an electric table fan. They cool people effectively by introducing slow motion into the still hot air of a room. Fans never really cool the air, unlike AC equipment, they actually heat the air due to heat exhaust from the motor and friction, but use much lower power (expensive thermodynamic air cooling). In contrast, the ceiling fan can also be used to reduce the stratification of warm air in the room by forcing it down to affect occupant sensation and thermostat readings, thereby increasing the energy efficiency of climate control.
Video Ceiling fan
Histori
The Pillion type of ceiling fan dates back to 500 BC, and is native to India. Unlike a modern swivel fan, this fan does move air by moving around, and is manually operated by cable.
The first spinning ceiling fans appeared in the early 1860s and 1870s, in the United States. At that time, they were not supported by any form of electric motor. Instead, a flowing water flow is used, along with a turbine, to propel a belt system that will change the blades of the two-blade fan unit. The system can accommodate several fan units, and become popular in shops, restaurants, and offices. Some of these systems still survive to this day, and can be seen in parts of the southern United States where they initially proved useful.
The electric powered ceiling fan was invented in 1882 by Philip Diehl. He has engineered the electric motor used in Singer's first electric-powered sewing machine, and in 1882 he adapted the motor for use in ceiling-mounted fans. Each fan has its own motor unit, without the need for a belt.
Almost immediately he faced fierce competition due to the commercial success of ceiling fans. He continued to make improvements to his invention and created a light kit mounted on a ceiling fan to combine the two functions in a single unit. In World War I, most of the ceiling fans were made with four blades, not the original two, which made the fans quieter and allowed them to circulate more air. The early 20th century companies that successfully commercialized the sale of ceiling fans in the United States were the Hunter Brothers division of Robbins & Myers, Westinghouse Corporation and Emerson Electric.
In the 1920s, ceiling fans were common in the United States, and had begun to take on the international world. From the Great Depression of the 1930s, until the introduction of electric air conditioning in the 1950s, ceiling fans slowly disappeared from fashion in the US, almost falling to total unused in the US in the 1960s; those remaining are regarded as nostalgic goods.
Meanwhile, electric ceiling fans are becoming very popular in other countries, especially those with hot climates, such as India and the Middle East, where lack of infrastructure and/or financial resources makes energy-hungry freon-based air conditioning equipment practically become impractical. In 1973, Texas HW (Hub) Markwardt entrepreneur began importing highly efficient ceiling fans to the United States manufactured in India by Crompton Greaves, Ltd. Crompton Greaves has been producing ceiling fans since 1937 through a joint venture formed by Greaves Cotton of India. and Crompton Parkinson from the UK, and has perfected the world's most energy-efficient ceiling fan thanks to a patented 20-pole induction motor with a highly efficient cast aluminum rotor that dissipates heat. The ceiling fan of Indian manufacturers was produced slowly at first, but Markwardt's Encon Industries branded ceiling fans (which stood for ENergy CONServation) finally found great success during the energy crises of the late 1970s and early 1980s, as they consumed much more less energy (under 70 years). watt electricity) than the old shaded polar motors used in most other American-made fans. Fans are becoming a very effective energy-saving tool for residential and commercial use by adding expensive air conditioners with cool cooling wind effects. The fan used for comfort creates a cold wind by increasing the heat transfer coefficient, but does not lower the temperature directly.
Because of this new commercial success using ceiling fans effectively as energy conservation applications, many American manufacturers are also beginning to produce, or significantly increase the production of ceiling fans. In addition to the imported Encon ceiling fan, Casablanca Fan Company was founded in 1974. Other American producers at the time included Hunter Fan Co. (then a division of Robbins & Myers, Inc.), FASCO (FA Smith Co.)..), and Emerson Electric; which is often branded as Sears-Roebuck.
Throughout the 1980s and 1990s, ceiling fans remained popular in the United States. Many small American importers, most of them rather short-lived, start importing ceiling fans. Throughout the 1980s, the sales balance between the American-made ceiling fans and those imported from factories in India, Taiwan, Hong Kong and eventually China changed dramatically with imported enthusiasts taking up the lion's share of the market in the late 1980s. Even the most basic US fans sell for $ 200 to $ 500, while the most expensive imported fans rarely exceed $ 150.
Since 2000, important breakthroughs have been made by companies such as Monte Carlo, Minka Aire, Quorum, Craftmade, Litex and Fanimation - offering higher ceiling fan prices with more decorative values. In 2001, Washington Post writer Patricia Dane Rogers wrote, "Like so many other ordinary household objects, this old building will be high-tech and stylish."
Maps Ceiling fan
Usage
Unlike air conditioning, fans only move the air - they do not directly change the temperature. Therefore, a ceiling fan which has a mechanism for reversing the direction in which the blades push the air (most often the electrical switch at the unit switch, motor home, or bottom canopy) can help in heating and cooling.
Some ceiling fans, mostly made by Hunter on or before 1984, can be mechanically rotated (have adjustable pitch blades) and not electrically reversible motors. In this case, the blade should be struck to the right (or left if the motor rotates clockwise) for downdraft, and left (or right if the motor rotates clockwise) for updraft. The Hunter Original Hotel is one such example. In very rare cases, such as the late 1984 Hunter Original, fans can be reversed mechanically and electrically reversible, which in this case can blow air, or down, in any direction. Some ceiling fans can only blow air in one direction and can not be reversed in any way, more often just downdraft, but rarely just updraft. This happens to most antique fans, and most industry fans.
For cooling, the direction of rotation of the fan should be set for the air to blow down (usually counterclockwise from below), except in rare cases where more wind will be felt when blowing up, such as when installed in the hallway where the slats will be very close to the wall. The propeller should lead with the upside down as they spin. The wind created by the ceiling fan speeds up the evaporation of sweat on human skin, which makes the body's natural cooling mechanism much more efficient. Because the fan works directly on the body, not by changing the temperature of the air, during the summer it is a waste of electricity to leave the ceiling fan when no one is in the room unless there is air conditioning, windows open, or anything that can heat the room (like an oven) and the fan just to move the air.
For heating, the ceiling fan should normally be set to change the opposite direction (usually clockwise, the propeller should rotate with the bottom side turned towards) and at low speed (or the lowest speed the fan is able to drain the air down to the floor). Natural water stratifies - that is, warm air rises to the ceiling while cooling air cools. Unfortunately, this means cooler on or near the floor where humans spend most of their time. A ceiling fan, with its rotation direction arranged so that air is pulled up, draws cooler air below, forcing warmer air near the ceiling to move down to take its place, without blowing airflow directly on the occupants of the room. This action serves to balance the temperature in the room, making it cooler near the ceiling, but warmer near the floor. Thus thermostats in the area can be set a few degrees lower to save energy, while maintaining the same level of comfort. It is important to run the fan at low speed (or the lowest speed of the fan capable of draining the air to the floor) to minimize the cold wind effect described above. But if the ceiling is high enough, or the lowest speed downdraft will not create a cold wind effect, it can be left on a downdraft year.
The additional use of ceiling fans is to combine them with air conditioning units. Through-window-through-window-AC units typically found in rental properties in North America typically have both air-cooling tasks indoors and circulating. Provided that the ceiling fan is suitable for the room in which it operates, the efficiency of air movement is much higher than that of the air conditioning unit, therefore, for peak efficiency, the AC should be set to a low fan suit and the fan ceiling should be used to circulate the air.
Part of the ceiling fan
The main components of the ceiling fan are as follows:
- Electric motor
- Blades (also known as paddles or wings) are usually made of wood, plywood, iron, aluminum, MDF or plastic
- Elbow iron (also known as a knife bracket, blade arm, knife handle, or flange), which holds the blades and connects them to the motor.
- Axle, metal or plastic wheels or a strong double rubber torque attached to the motor shaft, and which may be attached to the blade iron. The ring in the flywheel is locked on the shaft with the key screw, and the elbow iron to the outer ring with the bolt inserted into the tapped metal insertion. The rubber or plastic gears can become brittle and broken, a common cause of fan failure. Replacing the flywheel may require the release of cables and need to be removed from the switch housing located on the road to allow the flywheel to be removed and replaced.
- Rotor, alternative to iron knife. First patented by industrial designer Ron Rezek in 1991, the one-piece die-cast rotor receives and secures the blades and bolts directly to the motor, eliminating most of the balance problems and minimizing the open fasteners.
- Mechanism for installing ceiling fan such as:
- Ball-and-socket system. With this system, there is a piece of metal or plastic mounted on the end of the downrod; The hemisphere is located in a metal bracket mounted on the ceiling, or metal canopy, and allows the fan to move freely (which is very useful in the vaulted ceiling). Some companies have come up with little modifications of this design.
- J-hook System (Claw Hook). A type of mounting system in which the ceiling fan depends on the metal hook, which is attached to the ceiling. Grommet rubber is used to keep the fan firmly in place and helps avoid the vibrations in the ceiling.
- U-bolt System. Similar to the J-hook system, except that the hook on the ceiling is U-shaped and held by a screw. One advantage of the U-bolt system compared to J-hook's system is that it will not escape with fan torque in either direction. A J-hook can be loosened by the fan torque when rotating clockwise (or counterclockwise if the J-hook is a threaded left hand).
- Some fans can be installed using a low ceiling adapter, a special device that must be purchased from the fan manufacturer. This eliminates the need for downrod, and is therefore useful in rooms with low ceiling permits.
- In recent years, it is increasingly common for ball-and-socket fans designed so that the canopy can be optionally fastened directly to the top of the motor home; then the entire fan can be secured directly to the ceiling mount bracket. This is known as "close to the ceiling".
The typical ceiling fan weighs between 15 and 50 pounds when fully assembled. While many junction boxes can support that weight when the fan is still hanging, the fan in the operation provides a lot of extra pressure - especially the twist - on the hanged object; this may cause an incorrect connection box to fail. For this reason, in the United States, the National Electrical Code (document NFPA 70, Art. 314) states that a ceiling fan must be supported by an electrical connection box registered for that use. It is a common mistake for homeowners to replace lamps with ceiling fans without upgrading to the right junction box.
Fans/dangers hang low to limb
Another concern with installing ceiling fans is related to the height of the blade relative to the floor. Code building throughout the United States prohibits residential ceiling fans from being fitted with a knife closer than seven feet from the floor; this sometimes proves, however, not to be high enough. If the ceiling fan is turned on and someone fully extends his hand into the air, as it sometimes happens during normal tasks such as stretching or changing sheets, it is possible for a knife to attack their hands, potentially causing injury. Also, if one carries a long and awkward object, one end may inadvertently enter the ceiling rotation path of the ceiling fan blade, which may cause damage to the fan. Code building throughout the United States also prohibits industrial ceiling fans mounted with a knife closer than 10 feet from the floor for this reason.
MythBusters : "Killer Ceiling Fan"
In 2004, MythBusters tested the idea that the ceiling fan was able to decapitate if an individual stuck his neck to the running fan. Two versions of the myth were tested, with the first one being "jumping child", involving a child jumping on the bed, jumping too high and entering the fan from the bottom and the second being a "leap of lover", involving a husband wearing a costume, jumping toward his wife in the bed and into the side of the fan. Curry Byron, Tory Belleci, and Scottie Chapman lead the investigation, though native MythBusters Jamie Hyneman and Adam Savage also help.
First, Kari and Scottie buy ordinary household fan and also industrial fan, which has a metal blade compared to stronger wood and motor. They and Tory then formed their human analogs - Adam's ballistic gel statues with indigenous human craniums, pig spines for human thorns, and latex artifacts filled with fake blood - and then build rigs for both scenarios.
They solved the myths in both scenarios with household and industrial fans, as tests proved that residential ceiling fans, apparently by design, were largely unable to cause more than minor injuries, had low torque motors that stopped quickly when blocked and knives composed of light materials that tend to be easily broken when an impact (test household fan of the scenario "lover's leap" really solve the fan blades.) They found that fans of the industry, with steel blades and higher speed, proved capable of causing injury. and lacerations - building codes require industrial fan to be fitted with blades 10 feet above the floor, and test industrial fan of the scenario "leap lover" resulted in the injury lethal in which fan cut sliced ​​jugular and into the spine - but still lost energy quickly once blocked and can not decapitate the test doll. In closing, Scottie, Tory and Kari create a fan which is more dangerous with a lawnmower as a fan motor and a sharp knife made of sheet metal in an attempt to duplicate the results, and can not even reach the beheading, but it causes a deadly wound and terrible which forced Adam to put it in " MythBusters Hall of Fame."
Wobble
Wiggling is usually caused by the weight of the fan blades that are out of balance with each other. This may be due to a variety of factors, including a curved knife, a bent bent blade, a knife or a knife iron not screwed straight, or a knife to be of different weight or shape or size. (Minute Differences are important.) Also, if all the blades do not exert the same force in the air (because they have different angles, for example), the vertical reaction force can cause wobbling. Shaking can also be caused by motor defects, but it is very rare. Shake is not affected by the way the fan is installed or the mounting surface.
Contrary to popular misunderstandings, swaying alone will not cause the ceiling fan to fall. Ceiling fan secured with clevis pin locked with separate pins or R-clip, so wobble will not affect fan security, unless of course, pin/clip is not secured. To date, there have been no reports of fans wobbling from the ceiling and falling. However, severe wobble may cause light or cover shades to loosen gradually over time and potentially fall, incurring the risk of injury to anyone under the fan, as well as from broken glass produced. It is also worth mentioning that when MythBusters designed a fan for the purpose of cutting off a person's head, Scottie used edge searchers to find the exact part of their sword in order to eliminate potentially dangerous steel wobbles. It is important that, when installing the fan, the installer closely follows the manufacturer's instructions relating to the proper use of mounting screws. It is also important that all screws (especially the holding screws that hold the onset twist in place) become tight, and every ceiling fan fixture is properly assembled with their shades and securely closes.
References
Source of the article : Wikipedia
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