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Electrical Power for Arc Welding 140

Welding Training

Class Information

Tooling U classes are offered at the beginner, intermediate, and advanced levels. The typical class consists of 12 to 25 lessons and typically requires at least two hours of instruction time.

Class Name:	Electrical Power for Arc Welding 140
Description:	This class describes electrical variables, the path of electricity, and the effect of electricity on the arc welding process.
Prerequisites:	650115
Difficulty:	Beginner
Number of Lessons:	20

Class Outline
Objectives The Importance of Electricity What Is Electricity? Current Voltage Resistance Ohm’s Law Wattage Path of Electricity Grounding Direct Current and Alternating Current Uses of DC and AC Current Polarity Constant Current Constant Voltage Arc Blow Power Conversion Power Equipment Electrical Safety Summary

Class Objectives

Explain the importance of electricity.
Define how electricity flows in materials.
Define current.
Define voltage.
Define resistance.
Explain the relationship between electrical variables.
Define wattage.
Identify the components of an arc welding circuit.
Describe grounding.
Distinguish between direct current and alternating current.
Identify common uses of alternating current.
Identify common uses of direct current.
Identify types of polarity.
Describe common uses for constant current.
Describe common uses for constant voltage.
Describe arc blow.
Describe how power is converted for arc welding.
Identify features of welding equipment.
Explain risks involving electrical shock.

Class Vocabulary
alternating current	Current that regularly reverses the direction of its flow. AC is mostly limited to welding ferrous metals.
ammeter	A device that measures amperes in an electrical circuit. Some machines have built-in digital ammeters.
amp	A unit of measurement that indicates the amount of current flowing in a circuit. "Amp" is short for ampere.
ampere	A unit of measurement that indicates the amount of current flowing in a circuit. Arc welding uses high amperage.
arc	The area in which electricity jumps from the electrode to the workpiece. The heat generated by the arc melts the base metals.
arc blow	A condition that occurs when the arc does not follow its intended path from the electrode to the workpiece. Arc blow can cause undesirable weld beads.
arc length	The distance the arc stretches from the electrode to the workpiece. Longer arcs require more voltage.
arc welding	A fusion welding process that uses electricity to generate the heat needed to melt the base metals.
atom	The smallest distinguishable unit of a material that maintains the same characteristics of that material.
base metal	One of the two or more metals to be welded together to form a joint.
bead	The end product of a joint that has been welded.
circuit	A controlled path for electricity. A circuit includes a source, path, load, and control.
conductor	A material that allows for the flow of electricity. For a successful arc weld, electrodes and base metals must be good conductors.
constant current	Welding using a current that varies slightly with changes in voltage. Constant current, or CC, is often used in shielded metal arc welding (SMAW) and gas tungsten arc welding (GTAW).
constant voltage	Welding using a voltage that varies slightly with changes in current. Constant voltage, or CV, is often used for gas metal arc welding (GMAW) and flux-cored arc welding (FCAW).
consumable electrode	An electrode that conducts electricity to the arc but also melts into the weld as a filler metal.
control	The device that affects or alters the flow of current in a circuit. In arc welding, the control can turn the circuit on or off, and in most cases, adjust the voltage and amperage.
current	The rate and amount of electrical flow. Arc welding requires a continuous flow of electricity to maintain the arc.
current output	The maximum amount of current that a given welder can generate.
direct current	A current formed when electrons flow in one continuous direction. Many applications use DC current. Gas metal arc welding (GMAW) and flux-cored arc welding (FCAW) require DC.
directly proportional	A constant ratio between two values. If value A increases, value B also increases. If value A decreases then value B also decreases.
duty cycle	The amount of time in a ten-minute period that a welder can perform work without overheating. In the shop, welders with a higher duty cycle are preferred.
electrical shock	The flow of electricity through the human body. Electrical shock can be fatal.
electricity	The energy created by the movement of electrons. Electrical energy can be converted into light, heat, or motion.
electrode	A device that conducts electricity. In welding, the electrode also can act as the filler metal.
electromotive force	The force that pushes electrons through a conductor.
electron	A negatively charged particle that orbits the nucleus of an atom. Electrons move between atoms to cause electrical flow.
energy efficient	Not wasting electricity. Energy efficient devices do work using smaller amounts of electricity, which costs less.
ferrous metal	A metal that contains iron. Ferrous metals are the most common type of welded metal.
filler metal	A type of metal sometimes added to the joint in fusion welding. Filler metal adds to the strength and mass of the welded joint.
flux	A non-metallic material used to protect the weld puddle and solid metal from atmospheric contamination.
flux-cored arc welding	An arc welding process that uses a continuously fed consumable electrode that contains flux at its core. It is also referred to as FCAW.
formula	A general fact or principle that is expressed mathematically.
gas metal arc welding	An arc welding process in which the bare wire electrode and inert shielding gas are fed to the weld through a welding gun. It is also referred to as GMAW or MIG welding.
gas tungsten arc welding	A very precise arc welding process that uses a nonconsumable tungsten electrode. It is also referred to as GTAW or TIG welding.
ground	Safely connected to a neutral body, like the earth, which can absorb a stray electrical charge.
heat distortion	The undesirable physical change in a material due to excessive temperature changes.
incomplete fusion	Metals that have not been effectively welded together.
insulator	A material that inhibits the flow of electricity.
inversely proportional	A constant ratio between two values. If value A increases, then value B decreases. If value A decreases, then value A increases.
inverter	An energy efficient welder that is smaller than traditional welders, but has more electrical power.
load	The device that converts electricity into another form of energy, such as heat, light, or motion. In an arc welding circuit, the arc is the load.
low-carbon steel	A steel that has a carbon range between 1.05 and 0.30%. Also referred to as mild steel, low-carbon steel is the most commonly welded metal.
melting rate	The speed at which an electrode melts into the base metals. The melting rate of an electrode is a consideration when setting the voltage and amperage on a welder.
neutron	A particle with a neutral charge that is located in the nucleus of an atom.
nonferrous metal	A metal that does not contain iron. Nonferrous metals are more difficult to weld than ferrous metals.
ohm	A unit of measurement for electrical resistance.
Ohm’s Law	The law describing the relationship between voltage, amperage, and resistance. Ohm's Law states that volts equals amperes multiplied by ohms.
path	A conductor that directs electricity in a circuit. In welding, the path is often copper wire.
penetration	The distance below the surface of the base metals that the arc heat can melt the joint. The amount of current directly affects weld penetration.
polarity	The direction of current flow in a direct current (DC) circuit.
porosity	Unsightly gaps on the surface of the weld bead that form as a result of trapped gas during the welding process. Arc blow can cause porosity.
power	Work performed by electricity that appears in another form of energy such as heat, light, or motion.
primary voltage shock	An electrical shock from 120-480 volts that occurs in arc welding from touching a lead inside a switched-on welder and then touching the welder case or other grounded metal at the same time.
proportional	A constant ratio or relationship between two values. If one value changes, the other must change to maintain the same ratio.
proton	A particle with a positive charge that is located in the nucleus of an atom.
reactor	A device used in an electrical circuit that stabilizes and adjusts low voltage current into high amperage current.
rectifier	A device used in an electrical circuit that converts AC power to DC power.
resistance	The opposition to current flow. Electricity flows in the path of least resistance.
reverse polarity	Current in arc welding that flows from a negative workpiece to a positive electrode. Reverse polarity creates more heat at the electrode.
secondary voltage shock	An electrical shock from 60-100 volts that occurs in arc welding from touching the electrode while another part of the body touches the workpiece.
self-regulated	A term used to describe the arc in constant voltage arc welding applications. A change in arc length with CV welders automatically adjusts the electrode melting rate.
shielded metal arc welding	An arc welding process that uses a flux-coated rod. It is also referred to in the shop as SMAW or stick welding.
source	The device that supplies the current that flows throughout a circuit. A welder is an example of a source.
spatter	Liquid metal droplets expelled from the welding process. Spatter can leave undesirable dots of metal on a workpiece surface.
straight polarity	Current in arc welding that flows from a negative electrode to a positive workpiece. Straight polarity creates more heat at the workpiece.
transformer	A device used in an electrical circuit that reduces the voltage of incoming electrical power.
undercut	A gap left in a finished weld that should have been filled with weld metal. Undercut is unsightly but does not necessarily indicate a bad weld.
vaporize	The process by which a liquid becomes a gas. Vaporization of a metal can ruin a weld.
volt	A unit of measurement that indicates the degree of electrical pressure or potential.
voltage	The electrical force or pressure that causes current to flow in a circuit. Arc welding uses low voltage.
voltmeter	A device that measures the voltage in a electrical circuit. Some welders have built-in digital voltmeters.
watt	A unit of measurement that indicates the amount of electrical power in a circuit.
wattage	The amount of electrical power required by a device to work properly. For example, light bulbs are categorized by their required wattage.
welder	Either the person who performs a weld or the power source that provides the electricity needed to perform an arc weld. Printed materials may use both meanings of the term.
work cable	The path used in welding to conduct electricity from the welder to the workpiece. In welding, the cables are connected to the welder, the workpiece, and electrode, providing a closed electrical circuit.
work clamp	The component that, along with the electrode, comes in direct contact with the workpiece during welding. The work clamp is connected to the work cable.
workpiece	A part that is being worked on. The workpiece may be subject to cutting, welding, forming, or other operations.