Page 49 - CITS - Welder - Trade Theory

WELDER - CITS

Working principle to inverter welding machine
The size of the iron Core is taken from the length of time the magnetic field is created by it.

Inverter welding by solid state electronic parts varies from 60 Cycle/second to several thousand cycles per second.
Due to which the transformer for 7Lbs works done equal to a transformer of 100Lbs pound.

Advantages and Disadvantages of AC and DC welding

machine

Objectives: At the end of this lesson you shall be able to
• compare the advantages and disadvantages of AC welding
• compare the advantages and disadvantages of DC welding.

Advantages of A.C welding machines
i A low in initial cost due to simple and easy construction.
ii A low operating cost due to less power consumption.
iii No effect of arc blow during welding due to AC.

iv Low maintenance cost due to the absence of rotating
v Higher working efficiency.
vi Noiseless operation.

Disadvantages of AC welding
i It is not suitable for bare and light coated electrodes.

ii It has more possibility for electrical shock because of higher open circuit voltage.
iii Welding of thin gauge sheet, cast iron and non –ferrous metals will be difficult.
iv It can only be used where electrical mains supply is available.
Advantages of D.C welding machines

i Required heat distribution is possible between the electrode and the base metal due to the change of polarity
(positive 2/3 and negative 1/3).

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CITS : C G & M - Welder - Lesson 8&9