5.3 Chapter Conclusion

David Ridge

Summary

In this chapter, we learned about some basic principles of electricity as they apply to welding and some basics on how a welding machine works. We also saw that there is a wide variety of welding machines in use today, each with different capabilities and characteristics. Finally, we discussed some safety considerations that should be taken into account concerning welding machines and electrical power.

Welding machines are complex tools; understanding how they work takes time and study. However, the more familiar you are with the equipment you will be using, the better and safer of a welder you will be. A key aspect of being an effective welder is your knowledge of how to operate your welding machine.

Review Questions

  1. What part does voltage play in an electric current?
  2. What part does amperage play in an electric current?
  3. In what way(s) does voltage affect the weld?
  4. In what way(s) does amperage affect the weld?
  5. Direct Current Electrode Positive (DCEP) and Direct Current Straight Polarity (DCSP) are terms that both mean the same thing.
    1. True
    2. False
  6. Direct Current Electrode Negative (DCEN) and Direct Current Straight Polarity (DCSP) are terms that both mean the same thing.
    1. True
    2. False
  7. If the electricity in the welding system is flowing to the workpiece lead, across the arc, and back through the electrode lead, the welding machine is set up for:
    1. Alternating Current (AC)
    2. Direct Current Electrode Positive (DCEP)
    3. Direct Current Straight Polarity (DCSP)
    4. Direct Current Electrode Negative (DCEN)
  8. If the electricity in the welding system is flowing to the electrode lead, across the arc, and back through the workpiece lead, the welding machine is set up for:
    1. Alternating Current (AC)
    2. Direct Current Electrode Positive (DCEP)
    3. Direct Current Reverse Polarity (DCRP)
    4. Direct Current Electrode Negative (DCEN)
  9. In North America, Alternating Current (AC) operates at what Hertz, or cycles per second.
    1. 100
    2. 60
    3. 50
    4. 20
  10. What is the primary difference between Constant Current (CC) and Constant Voltage (CV)?
  11. Processes like Flux Cored Arce Welding (FCAW) and Gas Metal Arc Welding (GMAW) use Constant Current (CC) power.
    1. True
    2. False
  12. Please list three different types of welding power sources.
  13. What does the term Duty Cycle refer to?
  14. A welding machine has a list of its duty cycle ratings. The list reads as follows: 100% @ 90 amps, 80% @ 120 amps, 60% @ 150 amps, and 40% at 180 amps. If you needed to weld at 160-170 amps on a large weldment, approximately how long could you weld continuously with this machine? Would this machine be the best choice for a high-production environment? Why or why not?
  15. At what amperage can an electric current be lethal?
  16. Why is excess heat in a welding system bad? What can excess heat in the system indicate? How can it be corrected?

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Introduction to Welding Copyright © by Washington State Board for Community and Technical Colleges is licensed under a Creative Commons Attribution 4.0 International License, except where otherwise noted.