Shop Safety Locate first aid kit and eye wash station

To report a campus emergency Tell the attending instructor If not available or practical call 4440 and explain the situation to campus security

To report a medical emergency or fire Tell the attending instructor If very serious do not hesitate to call and stay on the line

First step to dealing with a fire Insure those in the shop are immediately aware of the fire Additional Fire Safety Do not hesitate to evacuate the building If out of control make sure is called (from a safe location)

Before using any new tool or piece of equipment Read the instructions and service procedures Ask questions DO NOT use any piece of equipment at Linn- Benton Community College until you have been checked out by an instructor

Before testing or diagnosing any unfamiliar machine or system Locate and read manufacturer procedures Pay special attention to any precautions Ask Questions before proceeding

first aid kit location Find this and tell me where for Lab #1

First aid for liquid in the eyes Flush with lots of clean water while holding eye open Do not rub eye Get medical attention after flushing for ten minutes Have A Partner Drive

List types of accidents or injuries to be reported to a supervisor Report all accidents and injuries even if minor Report any situation, tool or piece of equipment that you feel is unsafe or potentially hazardous

fire extinguisher location Find them and tell me where for Lab #1

Medications Medications that reduce alertness are a hazard Read the label Report to instructor

How can you tell if a substance is hazardous to your health Read labels Ask for MSDS documents Read textbooks Ask questions

Basic Electrical Theory

Resistance  Resistance is affected by: 1) atomic structure of the material 2) length of the conductor 3) cross sectional area (size) of the conductor 4) temperature of the conductor 5) condition of the conductor

Atomic Structure All materials have resistance to electron flow Materials with just a few electrons in their outer most orbit (valence ring) have low resistance

Materials with Low Resistance Copper, aluminum, lead, gold, silver, and many other metals make good electrical conductors. These materials have just one or two electrons in the valence orbit of the atom It is easy to make these “free” electrons travel between atoms

Materials with High Resistance WoodRubberPlasticsGlass These materials have many electrons in their outer “valence” electron orbit. It takes tremendous pressure (Voltage) to move electrons between these atoms

Resistance in a conductor The longer the wire….. ….. the more resistance it will have The skinnier the wire….. ….. the more resistance it will have

Resistance in a conductor The hotter the wire (or connection)….. ….. the more resistance it will have The more corroded the wire (or connector)….. ….. the more resistance it will have

For Electricity to Work: There must be a difference in electrical potential or pressure called...VOLTAGE A conductor for the amps to move through and Resistance to control the flow of electrons

Ohms Law E=IxR Voltage (Electromotive-force) is used up… to push Amperage (the Intensity of the current)… through a Resistance Increasing resistance will lower amp flow How will Increasing voltage affect the amp flow? Increase

Ohms Law E=IxR 1 volt can push 1 amp through 1  of resistance 12 volts can push 12 amps through 1  of resistance 12 volts can push 1 amp through 12  of resistance

E = I x R Define Resistance R esistance is the opposition to amp flow may be caused by heat, excessive amp flow, corrosion or any insulated material Resistance is required to perform “work”

Voltmeter Testing Available Voltage Voltage Drop checks for resistance must be performed on an operating circuit

Component Does Not Work Verify the problem Look for the obvious Check for available voltage Check for quality ground

12.6 V

0.0 V

12.6 V

Diagnosis Understand the system Use a Wiring Diagrams

0.0 V

12.6 V

0.0 V

Intermittent or Unsatisfactory Circuit Operation Verify the problem Look for the obvious Check for voltage drop across the load Check for voltage drop across the insulated or positive feed circuit Check for voltage drop across the ground

12.6 V

9.3 V

12.6 V

3.3 V

0.1 V