SMAW Principles
What current is an electric current that has alternating positive and negative currents called?
(AC) Alternating Current
What is an electric current that flows in one direction called?
(DC) Direct Current
What are the two main advantages to repair?
1) Cuts down the cost of replacement 2) It limits the components time out of commission
What are some disadvantages of SMAW?
1) Electrodes have a fixed length 2) Welding must be stopped frequently to remove slag 3) Not all metals can be welded with it because of their chemical make up
What shade is used for Welding beyond 75 to 200 amps?
10 shade
How should the rate of air flow be for a movable exhaust hood?
100 linear fpm
What shade is used for Welding beyond 200 to 400 amps?
12 shade
What shade is used for Welding over 400 amps?
14 shade
What is the range of voltage "out" for a SMAW machine?
18 to 36 volts
What is the adequate recommended ventilation for a fixed exhaust hood?
2000 cfm
What is the range of voltage "in" for a SMAW machine?
220 to 440 volts
What is the typical amperage output for a SMAW machine?
25 to 500 amps
What is the frequency range for AC current?
25, 40, 50, 60
What is the heat range for SMAW?
6,000°F to 10,000°F
What is the frequency for AC in the US?
60 cycles per second
What is the auto darkening range for Welding helmet?
8 through 14
What is any material that conducts electricity called?
A conductor
What does the flux coating create as the electrode burns?
A vapor shield
What is the amount of current in a circuit called?
Amperage (Amp)
What is used to measure the flow of amps?
An ammeter
What is the voltage during Welding called?
Arc Voltage (18 to 36 volts)
How are welding machines rated?
By their capacity at 60% work load
What kind of welding machine produces a steady supply of current to match the changes in arc length?
Constant Current
What kind of welding machine maintains a constant even arc length?
Constant Potential
What type of Welding machine, has the main advantage of greater flexibility, for materials of different thickness?
DC Welding machine
What kind of weld penetration does DC positive produce?
Deeper weld penetration
What kind of direct current, is referred to as straight polarity?
Direct Current Negative
What kind of direct current, is referred to as reverse polarity?
Direct Current Positive
What is installed on welding machines to turn off the power quickly?
Disconnect Switch
Why is SMAW so widely used?
Due to it versatility, portability, and inexpensive equipment
What is the rate of current change called?
Frequency
From what terminal does current always flow away from and toward?
From negative to positive terminal
What kind of Welding can a 400 to 600 amp machine do?
Heavy duty welding
What material can explode while welding if not properly vented?
Hollow Castings
What does the vapor shield created in SMAW do?
It shields the weld from outside contaminants
What kind of Welding, can an 150 to 200 amp Welding machine do?
Light, medium duty Welding
What is a condition that causes the arc to wander while welding in corners of thick metal?
Magnetic Arc Blow
What is SMAW most commonly used on?
Mild and low alloy steels
What does NEC stand for?
National Electric Code
What is the voltage produced when the machine is running but, no welding is being done?
Open circuit voltage (varies between 50 to 100 volts)
What indicates the direction of current flow in a circuit?
Polarity
What type of Welding machine can produce both AC and DC current and is more electrically efficient?
Rectifier
What is the opposition of material to current called?
Resistance
What kind of weld penetration does DC negative produce?
Shallow weld penetration
What is a process in which the Welding Arc is Shielded by the decomposition of the electrode covering?
Shielded Metal Arc Welding
What can occur if a welding machine is not properly grounded?
Stray current can develop on ungrounded machines and can cause severe shocks when touched
What kind of Welding can a 250 to 300 amp Welding machine do?
The most common all purpose jobs
What determines the current to be used in SMAW?
The type of metal being welded
What type of Welding machine is the least expensive, lightest, smallest, and takes power directly from a supply line?
Transformer
What is a control which spans a range of voltages and is used to set the open circuit voltage?
Variable Voltage
What pushes the current through the wire?
Voltage
What is it called when the voltage gets weaker as the distance from the generator increases?
Voltage Drop
How is heat generated for SMAW?
When an electric Arc forms between the electrode and the base metal
