Wld 40- final study guide
Most DC generators produce constant _____.
current
An alternator provides _____ current.
AC
Most GMAW is performed with a constant _____ power source.
voltage
True or false. A flashback is combustion in torch head, usually accompanied by a whistle sound.
True
True or false. An alternator's output can be rectified, but a generator's output cannot.
True
True or false. Globular transfer has excessive spatter and is not normally used?
True
True or false. Most regulators have two gauges.
True
True or false. Pulsed spray transfer has two heat levels.
True
MAPP gas and propane should use a grade _____ type hose.
T
Spray transfer is the _____ of the transfers.
fastest
Which hydro testing methods is the most common for high pressure cylinders?
water jacket volumetric expansion
True or false. Alternators and generators that produce single phase welding output is much smoother of an arc than three phase output can produce
False
True or false. Engine driven power sources only come as liquid cooled engines to provide the required duty cycle.
False
True or false. Federal laws only permit gasoline driven welders on off shore oil platforms.
False
True or false. Plasma arc cutting can only sever ferrous metals.
False
When Gas Tungsten Arc Welding (GTAW) first came out it was primarily use to weld on which type(s) of base metal?
both aluminum and magnesium
Pulsed spray transfer can be used in the _____ following position(s).
flat, horizontal, vertical and overhead
The key to regulator operation is a?
flexible diaphragm
Do not ever attempt to repair regulators or to substitute parts because:
only a certified repairman is allowed to work on regulators
Why are better brand electric grinders AC/DC input?
Because the can run on both ac and dc and can be used on a generator
Why can you overload an air-grinder without burning the unit out?
Because there are no windings to overheat if it stalls
Why is high input amperage important when purchasing electric grinders?
Because they have better windings
Which fuel is the most popular for engine drives?
Gasoline
Which DC polarity is most commonly used with the GTAW process?
Straight
Which DC polarity produces deep penetration?
Straight
True or False. Plasma is present in any electric arc.
True
True or False. The electrical contact is made at the contact tip?
True
True or false Air grinders only need to be oiled (air tool oil) every 6 months.
True
True or false. High frequency serves to start the arc initially without making contact to the work with the electrode.
True
True or false. Inductance is the amount of time the arc will stay on (or arc on time).
True
True or false. Plasma arc requires a constant current, step-up transformer power source.
True
True or false. Plasma torches can either be hand-held or machine-mounted.
True
True or false. The faster the wire feed speed, the higher the amperage output.
True
True or false. Tungsten has the highest melting point of all metals known.
True
True or false. When trying to refill a cylinder that has an expired last hydro test date, the cylinder cannot be filled and must be retested and stamped with a new hydro date after passing a hydro test and visual inspection.
True
What does C.F.M. stand for?
Cubic feet per minute
Voltage ranges for short circuit transfer are _____?
14-20 volts
As it pertains to welding there are _____ basic types of rotating power sources used.
2
There are _____ starting methods used to initiate the cutting arc.
2
The GTAW process can produce temperatures of up to _____ degrees Fahrenheit.
35,000
All high pressure cylinders must be hydrostatic tested every _____ years.
5
Plasma arcs operate at temperatures of up to _____ degrees Fahrenheit.
50,000
Most generators are _____ duty cycle machines as there is a small distance between the revolving rotor and the stator, resulting in little room for the flow of cooling air.
60%
Describe double insulated as it pertains to electric grinders.
Provides shock protection
Spray transfer can be used in the _____ following position(s).
flat and horizontal
Short circuit is the _____ of all metal transfers.
slowest
Which shielding gas has a deeper penetrating puddle?
helium
Which DC polarity produces cleaning action?
reverse
The different types of gases used for plasma arc include:
-nitrogen -oxygen -argon -air
A backfire may occur when:
-the torch is positioned too close to the work -loose connections -leaking hoses -incorrect gas pressures -anything that causes gas starvation at the tip
Basic testing of acetylene cylinders consist of:
-ultrasound test -pull valve and check porous material -check safety melt plugs for leakage -check for rusting pits, arc damage, fire, etc. -dents -external corrosion
Voltage ranges for spray transfer are _____?
23-34 volts
Liquid cooled engine drives should have their oil changed every _____ hours.
100-200
A star sign after the testing date indicates that the cylinder doesn't need to be tested until _____ years after the previous testing date?
10
A plus sign after the testing date indicates that the cylinder can be over filled by?
10%
Air cooled engine drives should have their oil changed every _____ hours.
100
Most alternators are _____ duty cycle machines as the internal cooling is so much better than a generator.
100%
A generator provides _____ current.
DC
GMAW uses a _____ type of power source.
DC
True or False. Plasma arc cutting requires preheat.
False
True or false. Air grinders run more quietly than electric grinders.
False
The _____ in a DC generator is were all the welding power is generated.
armature
Why is a two stage regulator better than a single stage regulator?
because it maintains the cylinder pressure to prevent fluctuation in pressure at the torch tip
The GTAW process uses a constant _____ type power source.
current
As it pertains to a DC generator, the brush and commutator system acts as a _____.
mechanical rectifier
What are the two main functions of a regulator?
to reduce high pressure gas stored in cylinders to working pressure for welding, cutting or heating and to maintain working pressure
True or false. An alternator can use a much smaller engine to produce the same welding amperage as a larger engine generator.
true
True or false. High frequency can break down some types of insulating jackets on welding cable.
true
