What is secondary power in welding?
Secondary power in welding refers to the power source that is used to supply the welding arc with energy. Unlike primary power, which is typically a transformer or generator, secondary power is the actual energy that is used to create the welding arc. This energy is usually in the form of electrical current and voltage, and it is the primary factor that determines the welding process and the quality of the weld.
The secondary power source can be either AC (alternating current) or DC (direct current), and it can be further classified into various types based on the current type, waveform, and other characteristics. The choice of secondary power source depends on the type of welding process being used, the material being welded, and the desired quality of the weld.
In this article, we will explore the different types of secondary power sources used in welding, their advantages and disadvantages, and how they affect the welding process.
Types of Secondary Power Sources
1. AC Power
AC power is the most commonly used type of secondary power source in welding. It is particularly suitable for welding ferrous metals, such as steel and iron. AC power has the advantage of being able to easily start the welding arc, which is important for ensuring good weld quality.
However, AC power has some disadvantages. One of the main drawbacks is that it can cause the weld to have a lower tensile strength compared to DC power. This is because AC power can cause the weld to have a higher degree of porosity and lack of fusion. Additionally, AC power can be less efficient than DC power, especially for welding thin materials.
2. DC Power
DC power is another commonly used type of secondary power source in welding. It is often preferred for welding non-ferrous metals, such as aluminum and copper, as well as for certain types of ferrous metals.
DC power has several advantages over AC power. It provides a more consistent and stable welding arc, which can result in higher tensile strength and better weld quality. DC power is also more efficient for welding thin materials, as it can provide a more focused and intense arc.
There are two types of DC power: straight (DC+) and reversed (DC-). The choice between these two types depends on the type of material being welded and the desired welding characteristics.
3. Constant Current (CC) and Constant Voltage (CV) Power Sources
Constant current (CC) and constant voltage (CV) power sources are two types of secondary power sources that are used to control the welding process. CC power sources maintain a constant current level throughout the welding process, while CV power sources maintain a constant voltage level.
CC power sources are commonly used for welding thick materials, as they provide a more stable and consistent welding arc. CV power sources, on the other hand, are often used for welding thin materials, as they allow for more precise control of the welding parameters.
In conclusion, the choice of secondary power source in welding is crucial for achieving high-quality welds. Understanding the different types of secondary power sources and their characteristics can help welders make informed decisions about the best power source for their specific welding applications.
