Personal safety practices
Remove jewelry, watches and rings
Tie hair back and avoid loose clothing
Do not play games in the shop
Be aware of other workers unsafe habits
List personal safety practices
when working in the shop
Wear safety glasses at all times when in the
shop area
Ask when not sure of any procedure
Wear non slip oil resistant soled leather
shoes
Personal safety practices
Do not wear contact lenses
Do not hesitate to remove yourself from any
unsafe environment
Understand the health risks of any
chemicals that you are using
Personal safety practices
Do not work when intoxicated or taking
medications that reduce your alertness
Do not work when you are over stressed or
tired
Do not attempt to lift any heavy object
without the proper tools or assistance
Personal safety practices
Do not work alone
Insure an instructor is present in the lab while
you are working on any project.
Basic Electrical Theory
Define Electricity
The ability to perform “work” by moving
electrons between atoms
Electron Movement
Heat, light or magnetism is created when
electrons move from atom to atom
Alternator provides power for running vehicle
Alternator provides power for running vehicle
Where do electrons come from?
• Atoms!
What is an atom?
an Atom consists of:
Electrons Protons
and Neutrons
Protons and neutrons
make up the nucleus
Like charges repel each
other but the neutrons “glue”
the protons in the nucleus
Electrons are repelled from each other, but attracted
to the protons. Energy (in the form of centrifugal force)
keeps the electrons moving in their orbital shell.
What is a Volt?
Voltage
Electromotive Force
(EMF)
the electrical pressure that forces
electrons to move from atom to atom
Voltage is present when there
is a difference in electrical
pressure
For Electrons to move between atoms
There must be a force to make them leave
or a “difference” in electrical pressure
These are “balanced” atoms
The electrons have no reason to leave the atom
An unbalanced atom is an “ion”
This ion has a negative charge
This ion has a positive charge
Opposite
Opposite Charges
Opposite Charges Attract
Similar
Similar charges
Similar charges repel
For current to flow there must be a positive
AND
a negative potential
Negative ion
Positive ion
To have voltage you must have a difference in
electrical pressure
The electromotive force between ions is called
VOLTAGE
Know your Voltmeter
• http://us.fluke.com/VirtualDemos/80_series
_V_demo.swf
Lab #3
Using the Voltmeter