chapter 2 Flashcards
It is essentially impossible to maintain a stable welding arc with the SMAW process and a constant voltage power source. (True/False)
Question options:
True
False
True
Early DC generators relied on ____________to produce welding power. (Multiple Choice)
Question options:
A) a chemical reaction
B) an induced voltage
C) an alternator
D) a transformer
B) an induced voltage
Microprocessor controls may be used for what type of welding processes? (Multiple Choice)
Question options:
A) SAW and SMAW only
B) GTAW and PAW only
C) Any process not using pulsed waveforms
D) Any process and pulsed waveforms
D) Any process and pulsed waveforms
The duty cycle of a welding power supply is based upon delivering its rated output for a given number of minutes out of a 10 minute period. Which of the following statement is correct? (Multiple Choice)
Question options:
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.
D) A 300 amp/60% duty cycle machine is rated to deliver 500 amps maximum for 6 minutes in a ten minute period.
D) A 300 amp/60% duty cycle machine is rated to deliver 500 amps maximum for 6 minutes in a ten minute period.
What are the possible causes if the arc stops and starts during welding? (Multiple Choice)
Question options:
A) Machine overload and the duty cycle is too low
B) An inert gas is too highly concentrated
C) Machine overload and the duty cycle is too high
D) Welding cables are too large
C) Machine overload and the duty cycle is too high
If the total length of a cable is 18 metres, which cable according to AWG (American Wire Gauge) would give you better conductivity? (Multiple Choice)
Question options:
A) 4
B) 2
C) 1
D) 1/0
A) 4
In some situations with the SMAW process, such as manual welding of pipe joints, a flatter slope is used to provide some change in current when arc lengths changes. (True/False)
Question options:
True
False
true
A rectifier consists of components that: (Multiple Choice)
Question options:
A) change DC power to AC power.
B) slow the dynamic response of the power source.
C) decrease the frequency of the power source.
D) change AC power to DC power.
D) change AC power to DC power.
What is meant by duty cycle?
Question options:
the length of time a diode can conduct electricity
how long a contact tip will last
the number of minutes, within a 10 minute period, during which a given welder can safely produce a particular welding current
the expected life of a welding power source
the number of minutes, within a 10 minute period, during which a given welder can safely produce a particular welding current
The two systems that can be used to adjust the output of a transistor welding power source are: (Multiple Choice)
Question options:
A) tapped transformer and SCR.
B) SCR and inverter.
C) frequency and pulse width modulation.
D) peak voltage and current feedback.
C) frequency and pulse width modulation.
Which of the following welding processes would be a better choice for welding a two-inch material with double V preparation? (Multiple Choice)
Question options:
A) FCAW
B) SMAW
C) PAW
D) SAW
A) FCAW
An advantage of using tapped transformers is: (Multiple Choice)
Question options:
A) it only uses DC current.
B) it only uses AC current.
C) it only provides specific current settings.
D) None of the above
B) it only uses AC current.ééééééé
Which was the first welding power source design to incorporate a feedback circuit? (Multiple Choice)
Question options:
A) Inverter
B) Mechanical reactor
C) Silicon-controlled rectifier
D) Saturable reactor
D) Saturable reactor
What is the component that is used in DC circuits to store and release voltage according to the circuit requirements? (Multiple Choice)
Question options:
A) Microprocessors
B) Diodes
C) Resistors
D) Capacitors
C) Resistors
When the core of a welding transformer is moved to adjust the output, this type of control is called a: (Multiple Choice)
Question options:
A) moving secondary.
B) tapped transformer.
C) moving shunt.
D) saturable reactor.
D) saturable reactor.
The first application of pulsed GMAW welding power sources was to: (Multiple Choice)
Question options:
A) provide low energy in the arc.
B) allow the spray transfer mode to be used in out of position welding.
C) limit the amount of spatter produced in the short circuit transfer mode.
D) provide balanced arc starting.
B) allow the spray transfer mode to be used in out of position welding.
The capacity to store and recall detailed welding variables in a welding power source is possible due to: (Multiple Choice)
Question options:
A) SCR controls.
B) saturable reactors.
C) feedback circuits.
D) microprocessor controls
D) microprocessor controls
To create or support an ionizing path in arc starting circuits for a high frequency setting, the ratio of volts to amps is: (Multiple Choice)
Question options:
A) 2 volts with 0.005 amps
B) 50 volts with 30 amps
C) 20,000 volts with 0.005 amps
D) None of the above
C) 20,000 volts with 0.005 amps
High frequency arc starting circuits use a __________________ to generate the high frequency. (Multiple Choice)
Question options:
A) spark gap
B) high speed switching transistors
C) inverters
D) SCRs
A) spark gap
What is the preferred polarity for GMAW and FCAW? (Multiple Choice)
Question options:
A) DCEN
B) DCEP
C) AC
D) AC balanced
B) DCEP
An advantage of inverter based power sources is that the circuitry is more simplified than the conventional transformer-based power source. (True/False)
Question options:
True
False
False
What is the purpose of an inverter? (Multiple Choice)
Question options:
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
B) To convert DC current to high frequency AC current22222222222
A pulsating weld pool that grows and shrinks significantly with each pulse produced by the power source results in: (Multiple Choice)
Question options:
A) lower penetration.
B) greater penetration.
C) a very large puddle.
D) a very small puddle.
B) greater penetration.
