Electrical Heating 01 - 03

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Electrical Heating Part - 01-03

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Electrical Heating 01 - 03

  1. 1. UTILIZATION OF ELECTRICAL ENERGYUNIT NAME OF UNIT 1 Electric Heating Electric Welding 2 Electrochemical Process Control Devices Electric Circuits – For AC 3 Illumination 4 Electric Traction 5 Traction Mechanics 6 Traction Motors, Control of traction Motors, Train Lighting Mr. Vijay Balu Raskar - Electrical Engineer
  2. 2. Introductionutilization of electrical energy Mr. Vijay Balu Raskar - Electrical Engineer
  3. 3. WHAT IS ELECTRIC HEATING ? WHAT IS THE PRINCIPLE BEHIND IT ?Electric heating is any process in which ELECTRICAL ENERGY is converted to “HEAT ENERGY”.Electric heating works on the principle of ”JOULE HEATING” (an electric current through a resistor converts electrical energy into heat energy.) Mr. Vijay Balu Raskar - Electrical Engineer
  4. 4. INTRODUCTION Electrical heating is based on the principle of thatwhen electric current passes through a mediumheat is produced. Let us take the case of solidmaterial which as resistance ‘R’ ohms and currentflowing through it is I amps for ‘t’ seconds than heatproduced in the material will be H=I²Rt Joules. Mr. Vijay Balu Raskar - Electrical Engineer
  5. 5. DOMESTIC APPLICATION OF ELECTRICAL HEATINGRoom heater for heating the buildingImmersion heater for water heatingHot plates for cookingGeysersElectric kettlesElectric IronElectric oven for baking productsElectric toasters etc… Mr. Vijay Balu Raskar - Electrical Engineer
  6. 6. INDUSTRIAL APPLICATIONMelting of metalsElectric weldingMouldling of glass for making glassappliancesBaking of insulatorMould ling of plastic componentsHeat treatment of pointed surpassesMaking of plywood. Mr. Vijay Balu Raskar - Electrical Engineer
  7. 7. ADVANTAGES OF ELECTRICAL HEATING OVER OTHER METHOD OF HEATING• Clean and atmosphere / Free from dirt.• No pollution / No flue gas is produced• Response quickly• Accurate Controlled temperature can made easily• Comparatively safe• Localized application• Overall efficiency is much higher• Uniform heating• Highest efficiency of utilization• Cheap furnaces• Mobility of job Mr. Vijay Balu Raskar - Electrical Engineer
  8. 8. TRANSFER OF HEATConduction:- This phenomenon takes placein solid, liquid and gas.Heat transfer is proportional tothe difference of temperatures between twofaces.No actual motion of molecules. Mr. Vijay Balu Raskar - Electrical Engineer
  9. 9. ConvectionThis phenomenon takes place in liquidand gas. Heat is transferred due toactual motion of moleculesRadiationThis phenomenon is confined tosurfaces. Radiant energy emitted orabsorbed is dependent on the natureof the surface. Mr. Vijay Balu Raskar - Electrical Engineer
  10. 10. CLASSIFICATION OF ELECTRICAL HEATING Power Frequency heating High Frequency heating1. Resistance heating 1. Induction heatinga. Direct Resistance heating a. Direct Core type Induction heatingb. Indirect Resistance heating b. Core less type induction heating2. Arc heating 2. Dielectric heatinga. Direct Arc heatingb. Indirect Arc heating Mr. Vijay Balu Raskar - Electrical Engineer
  11. 11. Classification of Heating Method:-Low Temperature Heating ± up to400°CMedium Temperature Heating ± from400°C to 1150 °CHigh Temperature Heating ± above1150 °C Mr. Vijay Balu Raskar - Electrical Engineer
  12. 12. Mr. Vijay Balu Raskar - Electrical Engineer
  13. 13. RESISTANCE HEATING (Example – Electric Water Heater) This method is based upon the I²R loss.Whenever current is passed through aresistor material heat is produced becauseof I²R losses.The generation of heat is done by electric resistor carrying current. Mr. Vijay Balu Raskar - Electrical Engineer
  14. 14. Characteristic Features of HeatingElements1) high resistivity2) able to withstand high temperatureswithout deterioration3) low temperature coefficient ofresistance4) positive temperature coefficientof resistance5)free from oxidation at hightemperatures Mr. Vijay Balu Raskar - Electrical Engineer
  15. 15. RESISTANCE HEATING DIRECT HEATING INDIRECT HEATING• Electric current is passed • Electric current is passed through highly resistive through the body (charge) material(heating element) to be heated. placed inside an oven.• High efficiency • Heat produced due to I2R loss• Example- in the element is transmitted to the body1) Electrode boiler for • Mode of heat transfer is heating water Conduction &/or Convection2)Resistance Welding &/or Radiation • Example- 1) Room Heaters 2) Domestic & commercial cooking 3) Heat treatment of metals Mr. Vijay Balu Raskar - Electrical Engineer
  16. 16. 1. DIREDCT RESISTANCE HEATING Mr. Vijay Balu Raskar - Electrical Engineer
  17. 17. 2. INDIRECT RESISTANCE HEATING Mr. Vijay Balu Raskar - Electrical Engineer
  18. 18. CAUSES OF FAILURE OF HEATING ELEMENTSFormation of hot spots.OxidationCorrosionMechanical failure Mr. Vijay Balu Raskar - Electrical Engineer
  19. 19. DIELECTRIC HEATING Mr. Vijay Balu Raskar - Electrical Engineer
  20. 20. Dielectric heating, also known as electronicheating, RF heating, high-frequencyheating and diathermy.Dielectric heating is a special way oftransforming electric current into heat.By the method of dielectric heating, generally,foils, plates and profiles with a thickness of 0,1-2,0 mm is are welded.We understand dielectric heating as thegeneration of thermal energy (heat) in a non-conducting material by the application of anelectromagnetic force or field t it. This is the Mr. Vijay Balu Raskar - Electrical Engineer
  21. 21. Mr. Vijay Balu Raskar - Electrical Engineer
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