1. Arc having Negative volt-ampere characteristics .
2. In AC arc welding (80 to 1oo volt of 0.35 lagging Power factor ) a high leakage transformer is used.
3. In DC arc welding (50 to 60 volt )motor generator set is used .
4. In carbon arc welding,carbon electrode is used .
5. Carbon arc welding is used for Weld Non-ferrous metal such as Brass, copper and their alloys.
6. Metal arc welding is better Quality of welding then Carbon Arc Welding .
7. Gas arc welding are of two types TIG & MIG .
8. In Ultrasonic Welding high frequency of 20 khz to 60 khz Vibrating Energy applied to Work piece .
9. In a Resistance Welding Ac supply used ,while In arc welding both AC/dc can be used.
10. In resistance welding externally Pressure required while in Arc welding not required.
11. Resistance welding has good power factor while in Arc welding has very Low Power Factor.
12. In Resistance welding Low voltage required while Arc welding high voltage required.
13. Types of Electrical Resistance Welding are Butt,Flash,Spot,Projection and Seam welding .
14.Types of Arc Welding are Metal Arc,Carbon Arc,Atomic Hydrogen,Helium or Argon Arc Welding.
15. Butt welding used in Welding Pipes ,Wired ,Rods While Flash Welding used in Tubes aircrafts , refrigerator etc
16. In a projection welding Flat electrodes are used it is possible to used several welding joints in one stroke.
17. In a seam welding Rolling Electrodes are used Continuosly Welding Possible upto 5 minutes.
18. Induction Heating and Dielectric Heating are the part of High Frequency Heating while Resistance Heating and Arc Heating are the part of Power frequency heating of 50 Hz.
19. Automatic temperature control - thermostate are used.
20. As compared to Core type Induction Furnaces ,Vertex core type /Ajax -wyatt furnace has low leakage reactance good power factor (0.8 to 0.85)and have no pinch effect.
21. Ajax -wyatt furnace is used for refining of brass or non ferrous metal.
22. Dielectric heating best method to heat Dielectrics (Insulator), frequency required is 10 to 30 Mhz and voltage 20 kV ,used for heating plastics ,drying in textile industries.
23. Direct Arc Furnace electrode is made up of graphite(best) and Carbon.
24. Indirect Arc Furnaces Arc having no contact with Metal Heat produced by Arc is transferred to the Metal by Radiation ,it is used to Melt the non-ferrous metal which having low melting point.
24.A The main application of Indirect Arc Furnace is to melt Non-Ferrous metals and intermittent work .
25. Induction heating can be used in both conducting and Magnetic material while Diectric heating used in only insulating material.
26. Example of indirect resistance heating is resistance oven etc.
27. Indirect resistance heating current passed through a wire of high resistance called heating element produces heat loss and heat transferred either by radiation or convection.
28. In motor ckt static frequency changers/ converters are used for speed regulation.
29. Travelling Speed of cranes varies 1 to 2.5 m/s.
30. Electric cranes require Huge Torque for Short time .So Short Time rated Motor Preffered for Overhead travelling cranes.
31. A double squirrel cage motor with Dol-starter is Powerful enough to drive a load conveyor belt.
32. Dc motors because of their inherent characterstics (smooth and precise speed control over the wide range ) are best suited for the Rolling mills.
33. Nominal voltage of lead-acid cells is 2.1 volt to 2 volt.
36. The voltage Rating of Batteries is based on the No. of cells connected in series.
37. The ampere-hour efficiency of lead-acid batteries is usually 90 to 95%.
38. The Operation of Thermocouple based on seeback effect.
39. Radiant heating is used for varnish and paint.
40. Application of Direct Resistance Heating is Electrode boiler,Salt Bath Furnace , Resistance welding.