The hair dryer works by using a heating element and fan. When plugged in, electric current heats the filaments in the heating element. The current also powers a motor that turns a fan. The fan blows air through the heating element, which warms the air. The warm air is then blown out of the dryer to dry hair by evaporating its water content faster. Safety features include a thermal fuse, temperature sensors, and insulation to prevent overheating.

1. How the hair dryer worksFor dummiesIonic 1800W BaBylissTechnological Design Engineering Annelies Rollez Academiejaar 2010-2011

2. 1. History1890: Alexandre F. Godefroy invented the hot air hairdyer1925: - First hairdryer appaered on the market. -100 watts of heat the hair doesn’t dry quickly - The hairdryers were made of steel and zinc heavy 1925 -1945: - optimize the design - 300 watts of heat1960: - Improvements in hairdryers’ technology: 500 watts of heat1970: - Improving the safety of the hairdryers - the Consumer Products Safety Commission (CPSC) recommend guidelines that would create safer products.1990: - Portable hairdryers: 1500 watts of heat - Plastic technology and insulating materials light weight2000- ...: - can reach 2000 watts of heatTechnological Design Engineering Annelies Rollez Academiejaar 2010-2011

3. 2. DisassemblyHeating-element with wrapped filaments Elements to have no filth into the fanAir shaftFan and motorThe housingTechnological Design Engineering Annelies Rollez Academiejaar 2010-2011

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5. 3. Working hair dryerHair dryer 2 superior parts : 1. Heating-element 2. Fan driven by a little motorWhen you put the plug into the plug-socket the electric current flow through the hair dryer2. Wrapped filaments of the heating element provided with that current warm up3. Current also will also drive the motor, which will next drive the fan4. The fan sucks air into the hair dryer air passes the filaments air takes up the warmth5. Heated air leaves the hair dryer and dries the hair because it accelerate the evaporation of the water on the hair. Heat air raises the temperature of the air around the hair.Technological Design Engineering Annelies Rollez Academiejaar 2010-2011

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9. 4. How each part works4.1. The motor4.1.1. Direct current motorElectromagnetism and magnets important For the motors’ working processThe principle of the working of the motor: Contradictory poles attract each other

10. Identical poles reject each other a rotating movement Technological Design Engineering Annelies Rollez Academiejaar 2010-2011

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13. 4.1.2. DC motor vs AC motorDC motors may be better for some very small applications costs less Smaller

14. Lighter

15. AC motors are rugged and reliable

16. AC motors can operate at higher speeds

17. AC motors are available in larger power ratings

18. For larger applicationsTechnological Design Engineering Annelies Rollez Academiejaar 2010-2011

19. 4.1.3. AC-DC converterBy means of diodes A diode conducts the current just in one directionIn this hair dryer: AC-DC converter = bridge rectifier consist of 4 diodesCurrent always flows in only one direction through the resistor.Alternating currentDirect currentTechnological Design Engineering Annelies Rollez Academiejaar 2010-2011

20. 4.2. The switchesTo control the heatTo control the air speedTechnological Design Engineering Annelies Rollez Academiejaar 2010-2011

21. 4.3. The heating elementNichrome wire aroundisolating elements of micaThe air that goes through the fan and passes the elements of the heating Element much colder than the Temperature of the nichrome wires.Because of that, the air will absorb the warmth of the heating element.the heat is dependent from the wattage of the hair dryer.Wattage electric current through the nichrome wire resistor Temperature Technological Design Engineering Annelies Rollez Academiejaar 2010-2011

22. 4.4. The fanThe air flow will be generated by the fanThe electric motor: electric energyAn air flowThrough the vent holes Protected with an gauze, which protects the hair dryer against dustTechnological Design Engineering Annelies Rollez Academiejaar 2010-2011

23. 4.5. Safety features4.5.1. Safety sensor- When the fan is broken, the hair dryer can be overheated. To Protect the hair dryer against it, the hair dryer will be supplied with a safety sensor.So when the temperature gets to high, the hair dryer will stop working.When the hair dryer is totally cooling down, then they can use it again. When the vents become clogged with hair of dust, the hair dryer becomes earlier overheated and so will stop working.Technological Design Engineering Annelies Rollez Academiejaar 2010-2011

24. 4.5.2. Safety cut off switchDryers contain a safety cut off switch that prevents the temperature of the drier from exceeding 60°C. Switch is a bimetallic strip made of a sheet composed of 2 different metals. Both sheets expand when heated, but each at different ratesWhen the temperature inside the hair dryer the sheets heat up and bendsWhen it reaches a certain point, it trips a switch that cuts off power to the hair dryer Technological Design Engineering Annelies Rollez Academiejaar 2010-2011

25. 4.5.3. Thermal fuseThermal fuse included in the heating elementWhen the temperature or the current were excessively high thermal fuse will blow and break Technological Design Engineering Annelies Rollez Academiejaar 2010-2011

26. 4.5.4. Ground Fault Circuit interrupter (GFCI)Is used to prevent accidental electrocutionby comparing the electrical going out through the black wire against that coming back through the white wire. If the difference is more than .005 amp, the system will be shut off.Technological Design Engineering Annelies Rollez Academiejaar 2010-2011

27. 4.5.5. InsulationThis is a sheet that’s around the heating element and that prevents the exterior of the hair dryer from getting hot.Technological Design Engineering Annelies Rollez Academiejaar 2010-2011