Shop Safety Locate first aid kit and eye wash station.

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 9911

9- 911and 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 9-911 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

Wood Rubber Plastics Glass

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

Resistance 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

12.6 V

12.6 V

12.6 V

12.6 V

12.6 V

12.6 V

12.6 V

12.6 V

0.0 V

0.0 V

0.0 V

0.0 V

12.6 V

Diagnosis

Understand the system

Use a Wiring Diagrams

0.0 V

0.0 V

12.6 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