TheoryCWENG Test Prep Practice Questions
Free CWENG Test Prep practice questions with answers and plain-English explanations. Browse the PDF, video and online mock test.
CWENG Test Prep Questions
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Q1In a constant current (CC) arc welding circuit, what happens to the current when the arc length changes?
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✓ Correct answer: The current remains relatively stable while the voltage changes
Constant current power sources maintain a relatively stable amperage despite changes in arc length, which causes voltage to change instead. This makes them ideal for processes where maintaining consistent amperage is critical, such as SMAW.
Q2What is the function of a rectifier in a DC arc welding power source?
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✓ Correct answer: To convert AC to DC
Rectifiers convert alternating current (AC) to direct current (DC) by allowing current to flow in only one direction, which is essential for DC welding applications.
Q3In welding circuit analysis, what does open circuit voltage (OCV) represent?
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✓ Correct answer: The voltage present when no welding arc is established
Open circuit voltage is the voltage measured across the output terminals of a welding power source when no welding is taking place (no current flowing). It must be high enough to establish an arc but not excessive for safety reasons.
Q4Which of the following best describes a constant voltage (CV) arc welding circuit?
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✓ Correct answer: The power source maintains voltage at a set point while current self-adjusts
In constant voltage circuits, the power source maintains relatively stable voltage while allowing current to vary based on the physical distance between the electrode and workpiece. This self-regulation makes them ideal for GMAW (MIG) welding.
Q5What component in an inverter welding power source allows for high-frequency operation?
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✓ Correct answer: Transistors
Transistors (specifically IGBTs or MOSFETs) in inverter welding power sources rapidly switch the current on and off at high frequencies, allowing for more efficient and compact designs compared to traditional transformer-based power sources.
Q6According to Ohm's Law, what happens to current in a welding circuit if resistance increases while voltage remains constant?
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✓ Correct answer: Current decreases
Ohm's Law (I = V/R) dictates that current is inversely proportional to resistance when voltage is constant. If resistance increases, the current will decrease proportionally.
Q7Which electrical characteristic is most important to control in SMAW (Stick) welding circuits?
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✓ Correct answer: Current (amperage)
SMAW welding uses a constant current (CC) characteristic where the amperage remains relatively stable despite changes in arc length. This helps maintain a stable arc even with hand movement variations.
Q8In an arc welding circuit, what is the primary purpose of an inductor?
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✓ Correct answer: To stabilize the arc by resisting rapid changes in current
Inductors in welding circuits create a choke effect that helps stabilize the arc by resisting rapid changes in current, reducing spatter and improving weld quality.
Q9What effect does increased inductance have on a GMAW (MIG) welding circuit?
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✓ Correct answer: Reduces spatter by smoothing current transitions
Increased inductance in GMAW circuits smooths out current fluctuations, reducing spatter by slowing the rate of current change during short circuits and arc re-ignition.
Q10What is the relationship between duty cycle and current output in a welding power source?
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✓ Correct answer: As current output increases, duty cycle decreases
Duty cycle and current output have an inverse relationship. Higher current outputs can only be sustained for shorter periods (lower duty cycle) due to heat generation in the power source components.
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