GOVERNMENT ENGINEERING COLLEGE DAHOD TOPIC :- ARC WELDING TRANSFORMER SUBJECT :- ELEMENTS OF ELECTRICAL DESIGN PRESENTED BY:- 130180109002 130180109014 130180109054 130180109086 130180109116 130180109106 GUIDED BY :- PROF :- SHAH PREET

. INTRODUCTION FIGURE

WELDING Welding is a process of joining two or more pieces of the same or dissimilar materials to achieve complete coalescence. Welding is accomplished by the use of heat and pressure. Welding is the only method of developing monolithic structure.

ADVANTAGES A large number of metals/alloys which are similar or dissimilar can be joined by welding. Welding permits considerable freedom in design.

POINTS TO REMEMBER Electric arc started by striking work with electrode Heat of arc melts electrode and surface of base metal Tiny globules of molten metal form on tip of electrode and transferred by arc into molten pool on work surface After weld started, arc moved along work

ELECTRIC ARC WELDING TRANSFORMER

A. C. transformers Used to step down a. c. line power voltage to a. c A.C. transformers Used to step down a.c. line power voltage to a.c. welding voltage Open circuit voltage runs between 50-100 volts Drops to arc voltage when arc struck Arc voltages Range: 36 volts (long arc) to 18 volts (short arc) Determined by arc length held by welder and type of electrode used

Voltage generated by welding machine when no welding being done Machine running idle Arc voltage Voltage generated between electrode and work during welding Load voltage Voltage at output terminals of welding machine when arc is going Combination of arc voltage plus voltage drop in welding circuit

Device used for holding electrode mechanically Conveys electric current from welding cable to electrode Insulated handle protects hand from heat Jaws of holder grip electrode at any angle Made of metal with high electrical conductivity and ability to withstand high temperatures

REQUIREMENTS FOR WELDING ANY METAL

Ear Protection Flume Protection ALSO PROTECT Ear Protection Full ear muffs that cover entire ear or ear plugs Dangers Noise Hot weld spatter or slag entering ear canal Flume Protection Always use proper ventilation to keep head out of fume plume.