CWB Level 2 Study Modules 4-5-6-7-8-9-12-
17-18-19-22 UPDATED ACTUAL Exam
Questions and CORRECT Answers
During arc welding there is a zone adjacent to the weld metal that reaches high temperatures but
does not melt. What is the name of this region? - CORRECT ANSWER - Heat Affect Zone
(HAZ)
In parallel electrical circuits, the voltage across each resistor is the same since each path is
connected to the same voltage source. Select the correct statement.
A. in each parallel path the resistance must be equalized to create equal voltage.
B. the current flowing in each parallel path must be the same as the voltage.
C. the current flowing in each parallel path depends on the resistance in each path
D. the current flowing in each parallel path depends on the capacitance in each path - CORRECT
ANSWER - C. the current flowing in each parallel path depends on the resistance in each
path
Welding is a joining process that by definition requires: - CORRECT ANSWER - The
application of either heat or pressure
The duty cycle of a welding power supply is based upon delivering its rated output for a
given number of minutes. Which of the following statements is correct.
A. a 300 amp/60% duty cycle machine is rated to deliver 300 amps for 6 minutes in a ten minute
period
B. a 300 amp/30% duty cycle machine is rated to deliver 300 amps in a ten minute period
C. a 250 amp/30% duty cycle machine is rated to deliver 250 amps for 30 minutes separated by
10 minutes at rest
D. a 300 amp/60% duty cycle machine is rated to deliver 500 amps maximum for 6 minutes in a
ten minute period - CORRECT ANSWER - A. a 300 amp/60% duty cycle machine is rated
to deliver 300 amps for 6 minutes in a ten minute period
,Conventional transformer-rectifiers;
A. convert direct current into alternating current
B. convert alternating current into direct current
C. convert alternating current into pulsed current
D. convert direct current into pulsed current - CORRECT ANSWER - B. convert
alternating current into direct current
A conventional diode placed in a circuit allows the passage of current in one direction only. A
silicon controlled rectifier(SCR) operates slightly differently. How does it work?
A. an SCR conducts current in both directions until turned on and current flow is then prevented
B. an SCR is non-conductive until turned onland then allows current to flow in both directions
C. an SCR is non-conductive until turned on, allowing current to flow in one direction only until
the flow of current stops
D. an SCR is a unique rectifying device which allows only alternating c1:1rrent to flow until
turned off - CORRECT ANSWER - C. an SCR is non-conductive until turned on, allowing
current to flow in one direction only until the flow of current stops
What is the term for voltage measured across the output terminals of a welding
machine when no current is being drawn?
A. diode voltage
B. operating voltage
C. open circuit voltage
D. terminal voltage - CORRECT ANSWER - C. open circuit voltage
A 60% duty cycle means that the power supply can deliver its rated output for:
A 60% of the rated output only
B. 60% over the rated output followed by 4 minutes at rest
C. 6 minutes at rest followed by 4 minutes at rated output
D. 6 minutes at rated output followed by 4 minutes at rest - CORRECT ANSWER - D. 6
minutes at rated output followed by 4 minutes at rest
,The DC output of a single phase power supply can be "ripply" and does not produce
the friendliest DC arc. How is this problem overcome?
A. single phase power supplies produce the smoothest DC of all common machines
B. a third transformer is added to the output circuit to filter out instability
C. a capacitor or capacitor bank is added to the output circuit
D. a 'dual' rectifier bridge is used to filter the transformer output - CORRECT ANSWER -
C. a capacitor or capacitor bank is added to the output circuit
One of the simplest ways of controlling the output of a welding transformer is to change
the efficiency of coupling between the primary and secondary coils. How can this be done?
A slide a piece of wood between the primary and the secondary coils
B. design the transformer with either a moving core or moving primary coils
C. design the transformer with a number of taps to select different output curves
D. use the timed firing of SCR's to control total conduction time - CORRECT ANSWER -
B. design the transformer with either a moving core or moving primary coils
When choosing between AC and DC output;
A. the process generally determines the type of current
B. high current output machines are always both AC/DC
C. DC is generally used for very high output applications
D. most supplies are equipped with constant voltage/constant current options - CORRECT
ANSWER - A. the process generally determines the type of current
Which of the following metals has the lowest electrical resistivity?
A aluminum
B. tungsten
C. copper
D. iron - CORRECT ANSWER - C. copper
, What is the purpose of an inverter?
A. to convert AC current to DC current of the same frequency
B. to convert DC current to high frequency AC current
C. to convert AC current to DC current
D. to convert electrode positive to electrode negative - CORRECT ANSWER - B. to
convert DC current to high frequency AC current
How is power flow analyzed in alternating current circuits?
A. AC circuits can be evaluated the same as DC circuits when RMS values of voltage
and current are used
B. when analysing AC circuits, inductive and capacitive reactance must be included
C. average current in an AC circuit is zero and therefore no work is done
D. the peaks and valleys of sine wave curves balance to zero with the load - CORRECT
ANSWER - C. average current in an AC circuit is zero and therefore no work is done
Which of the following methods is commonly used to control the output of a transformer?
A. an auxiliary power supply which feeds the secondary as required
B. a saturable reactor in series with the output
C. resistance placed in parallel with the primary of the transformer
D. taps on the secondary of the transformer - CORRECT ANSWER - D. taps on the
secondary of the transformer
A transformer type welding power source without a rectifier outputs what type of current?
A. direct current
B. alternating current
C. high frequency current
D. pulsed direct current - CORRECT ANSWER - B. alternating current
17-18-19-22 UPDATED ACTUAL Exam
Questions and CORRECT Answers
During arc welding there is a zone adjacent to the weld metal that reaches high temperatures but
does not melt. What is the name of this region? - CORRECT ANSWER - Heat Affect Zone
(HAZ)
In parallel electrical circuits, the voltage across each resistor is the same since each path is
connected to the same voltage source. Select the correct statement.
A. in each parallel path the resistance must be equalized to create equal voltage.
B. the current flowing in each parallel path must be the same as the voltage.
C. the current flowing in each parallel path depends on the resistance in each path
D. the current flowing in each parallel path depends on the capacitance in each path - CORRECT
ANSWER - C. the current flowing in each parallel path depends on the resistance in each
path
Welding is a joining process that by definition requires: - CORRECT ANSWER - The
application of either heat or pressure
The duty cycle of a welding power supply is based upon delivering its rated output for a
given number of minutes. Which of the following statements is correct.
A. a 300 amp/60% duty cycle machine is rated to deliver 300 amps for 6 minutes in a ten minute
period
B. a 300 amp/30% duty cycle machine is rated to deliver 300 amps in a ten minute period
C. a 250 amp/30% duty cycle machine is rated to deliver 250 amps for 30 minutes separated by
10 minutes at rest
D. a 300 amp/60% duty cycle machine is rated to deliver 500 amps maximum for 6 minutes in a
ten minute period - CORRECT ANSWER - A. a 300 amp/60% duty cycle machine is rated
to deliver 300 amps for 6 minutes in a ten minute period
,Conventional transformer-rectifiers;
A. convert direct current into alternating current
B. convert alternating current into direct current
C. convert alternating current into pulsed current
D. convert direct current into pulsed current - CORRECT ANSWER - B. convert
alternating current into direct current
A conventional diode placed in a circuit allows the passage of current in one direction only. A
silicon controlled rectifier(SCR) operates slightly differently. How does it work?
A. an SCR conducts current in both directions until turned on and current flow is then prevented
B. an SCR is non-conductive until turned onland then allows current to flow in both directions
C. an SCR is non-conductive until turned on, allowing current to flow in one direction only until
the flow of current stops
D. an SCR is a unique rectifying device which allows only alternating c1:1rrent to flow until
turned off - CORRECT ANSWER - C. an SCR is non-conductive until turned on, allowing
current to flow in one direction only until the flow of current stops
What is the term for voltage measured across the output terminals of a welding
machine when no current is being drawn?
A. diode voltage
B. operating voltage
C. open circuit voltage
D. terminal voltage - CORRECT ANSWER - C. open circuit voltage
A 60% duty cycle means that the power supply can deliver its rated output for:
A 60% of the rated output only
B. 60% over the rated output followed by 4 minutes at rest
C. 6 minutes at rest followed by 4 minutes at rated output
D. 6 minutes at rated output followed by 4 minutes at rest - CORRECT ANSWER - D. 6
minutes at rated output followed by 4 minutes at rest
,The DC output of a single phase power supply can be "ripply" and does not produce
the friendliest DC arc. How is this problem overcome?
A. single phase power supplies produce the smoothest DC of all common machines
B. a third transformer is added to the output circuit to filter out instability
C. a capacitor or capacitor bank is added to the output circuit
D. a 'dual' rectifier bridge is used to filter the transformer output - CORRECT ANSWER -
C. a capacitor or capacitor bank is added to the output circuit
One of the simplest ways of controlling the output of a welding transformer is to change
the efficiency of coupling between the primary and secondary coils. How can this be done?
A slide a piece of wood between the primary and the secondary coils
B. design the transformer with either a moving core or moving primary coils
C. design the transformer with a number of taps to select different output curves
D. use the timed firing of SCR's to control total conduction time - CORRECT ANSWER -
B. design the transformer with either a moving core or moving primary coils
When choosing between AC and DC output;
A. the process generally determines the type of current
B. high current output machines are always both AC/DC
C. DC is generally used for very high output applications
D. most supplies are equipped with constant voltage/constant current options - CORRECT
ANSWER - A. the process generally determines the type of current
Which of the following metals has the lowest electrical resistivity?
A aluminum
B. tungsten
C. copper
D. iron - CORRECT ANSWER - C. copper
, What is the purpose of an inverter?
A. to convert AC current to DC current of the same frequency
B. to convert DC current to high frequency AC current
C. to convert AC current to DC current
D. to convert electrode positive to electrode negative - CORRECT ANSWER - B. to
convert DC current to high frequency AC current
How is power flow analyzed in alternating current circuits?
A. AC circuits can be evaluated the same as DC circuits when RMS values of voltage
and current are used
B. when analysing AC circuits, inductive and capacitive reactance must be included
C. average current in an AC circuit is zero and therefore no work is done
D. the peaks and valleys of sine wave curves balance to zero with the load - CORRECT
ANSWER - C. average current in an AC circuit is zero and therefore no work is done
Which of the following methods is commonly used to control the output of a transformer?
A. an auxiliary power supply which feeds the secondary as required
B. a saturable reactor in series with the output
C. resistance placed in parallel with the primary of the transformer
D. taps on the secondary of the transformer - CORRECT ANSWER - D. taps on the
secondary of the transformer
A transformer type welding power source without a rectifier outputs what type of current?
A. direct current
B. alternating current
C. high frequency current
D. pulsed direct current - CORRECT ANSWER - B. alternating current
