Transcript Day 2
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