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Idaho Agricultural Extension Service Bulletin 396 June, 1962 T-1

ELECTRICITY FOR THE 4-H SCIENTIST

Safety Uses Economy

Division I 4-H Electric

University Of Idaho College of Agriculture

HOW TO USE THIS BOOK IN FULFILLING THE GOALS OF THE 4-H ELECTRIC PROJECT FOR THE FIRST AND SUCCEEDING YEARS

The minimum goals for credit in the 4-H Electric project vary according to the 4-H member's age and the number of years he or she has taken the electric project. For example, if you are a 4-H member beginning the 4-H Electric project at the age of 10, you will not be required to earn as many credit points as a 14-year-old 4-H member beginning the 4-H Electric project. However, if you are a 12-year-old in your second year of electricity you must earn as many credit points in that year as a 14-year-old does in his or her first year.

Each lesson or goal has been designated a certain number of credit points. These are shown near the title of each lesson or goal. You decide on the lessons you want to study, list them, and add up the credit points.

For a full year's 4-H project credit, the total of your credit points should be at least as many as shown in the following table:

Examples of reading the table below are as follows: (a) An 11-year-old member is required to complete 13 credit points the first year, (b) A 14-year-old is required to complete 17 credit points his first year, (c) A 14-year-old taking the electric project for the third year must complete 16 credit points that year.

We recommend that, if you are taking the 4-H Electric project, you start with the first lesson in the book and go on through to the back of the book in advanced years. But you may skip the less important or less interesting parts so long as you learn the basic lessons. A way to find out whether you know the basic lessons is to read them through and try to answer all questions under the heading "What Did You Learn." If you can answer these questions you may not wish to spend the time doing the things listed under "What To Do."

Minimum Number of Credit Points Required for Each Year's Work in the 4-H Electric Project

4-H Member's| 4-H Member's Year in 4-H Electric Project Age | | 1st Year | 2nd Year | 3rd Year | 4th or | | | | Later Years 10-11 | 13 | 15 | | 12-13 | 15 | 17 | 19 | 20 14-15 | 17 | 19 | 21 | 21 16 & over | 19 | 21 | 21 | 21

This system of credit points makes it possible for you to do the things you want to do with electricity and get credit for them in the 4-H Electric project.

4-H Electric, Division I

TABLE OF CONTENTS

Lesson Credit Page Number Title Points Number How to Use This Book 1 B-1 Getting Acquainted With Electricity 3 2 B-2 Tools for Electricians 4 7 B-3 Rewire a Lamp--Be a Lamp Detective 3 11 B-4 Make a Trouble Light 3 15 B-5 What Makes Motors Run 5 18 B-6 Taking Care of Electric Motors 3 23 B-7 Reading the Electric Meter 4 26 B-8 Ironing is Fun 3 30 B-9 Let's Be Friends With Electricity 2 35 B-10 How Electric Bells Work--For You 3 39 B-11 First Aid for Electrical Injuries 2 43 B-12 How Electricity Heats 3 47 B-13 Mysterious Magnetism 2 50 B-14 Give Your Appliances and Lights a Square Meal 2 54 B-15 You Can Measure Electricity 4 58

UNIVERSITY OF IDAHO COLLEGE OF AGRICULTURE AGRICULTURAL EXTENSION SERVICE Eric B. Wilson, Extension Agricultural Engineer 1962

Published and distributed in furtherance of the Acts of May 8 and June 30, 1914, by the University of Idaho Extension Service, James E. Kraus, Director; and the U. S. Department of Agriculture, Co-operating.

LESSON NO. B-l

Credit Points 3

GETTING ACQUAINTED WITH ELECTRICITY

Electricity serves you best when you understand how it works and use it properly. As a 4-H member, you should know about electricity and help to show others the way to obtain its tremendous work-saving benefits as well as how to use it with safety.

A good way to think of electricity is to compare it with water. It acts a lot like water. However it is made of tiny parts of atoms called electrons. When there are more than the normal number of electrons in anything, it is said to be negatively charged; when there is a shortage of electrons, it is positively charged. As water flows downhill, "seeking it's level," electrons flow from negative to positive, seeking to "balance" the charge.

Electrical Conductors

Even if you're never going to repair a lamp or make a chick brooder, you should know about conductors and insulators. This is because you happen to be a fairly good conductor of electricity. Electricity will pass easily through you to other conductors--the ground, for instance. When this happens you may get a shock, burn, or serious injury. But it doesn't ever have to happen, if you learn to understand your friend, electricity.

Silver, copper, iron, aluminum and many other metals are very good conductors. Water, acids, and salts are too. Electricity passes over or through them very easily. Like water pipes, the larger the conductor, the more electricity it can carry. When conductors are too small for the amount of electrons trying to move over them, they get hot, melt, may start fires. That's why wire size is important.

Electrical Insulators

Insulators are the opposite of conductors. Electricity has trouble passing through some materials. Rubber, most plastics, dry wood, oils and glass are some of the good insulators. It's the amount and kind of insulation that counts. If it has enough force, electricity can pass through just about anything--even jump gaps!

Electricity, like water, flows along the easiest paths. It is always trying to get to the ground. The earth attracts it. It stays on the wires unless a person, a wet branch, or some other conductor gives it a path to the ground. Do not touch any wire which might be carrying electricity.

Play It Safe

If you should touch a "hot" wire accidentally and are standing on a dry piece of wood, the conducting pathway to the ground is not good and the electricity may keep running along its wire. But do not touch some other conductor with another part of your body. This would complete a circuit through your body and would be very dangerous. Always make sure there is plenty of good insulation material or plenty of distance between you and anything which might be carrying electricity.

Remember, too, insulation is of little use when it is wet. Dew, mist, rain, condensation, a damp floor can change the whole picture. If you understand electricity and how it acts, you'll be safe enough, because you won't take chances or expose yourself to injury.

Electrical Terms

_Alternating Current_--Usually referred to as "AC," alternating current is current which reverses its direction of flow at regular intervals, 60 times a second.

_Direct Current_--"DC" current flows only in one direction. Battery current is DC.

_Ampere_--Amperes are units by which the rate of flow of electrical current (electrons) is measured. An ampere is 6.3 billion electrons passing one point in a circuit, in one second. This compares with the way the flow of water is measured in gallons per second.

_Volts_--A volt is a unit to measure the tendency of electrons to move when they are shoved. Voltage is the amount of "push" behind the electrons. It's like water pressure in a pipe. Home power lines carry 115 volts (110 to 120 volts). For appliances such as electric stoves, washers and driers, a second 115-volt line should be added, giving 230 volts (220 to 240 volts).

_Watts_--Watts equal volts times amperes. Light bulbs, electric irons and other appliances are usually marked with the voltage they require and the number of watts.

_Kilowatts_--Your electric bill usually reads in kilowatt hours. A kilowatt is 1000 watts. A kilowatt hour equals 1000 watts used for 1 hour. One kilowatt equals about 1-1/3 horsepower. A kilowatt is usually indicated by "kw" and a kilowatt hour by "kwh."

_Circuits_--A closed circuit is one in which the electricity is flowing, lighting a light, running a motor, or some other appliance. The circuit runs all the way from the place the electricity is being generated to your home, through the appliance or light bulb, and back to the generator.

Circuits are opened and closed by switches. When the circuit is opened, the electricity stops at the switch. Before working on a switch, socket, fuse, or any part of the wiring be sure to open the main switch. The main switch is usually at the fuse box or near it. Appliances should be disconnected when you work on them. Everyone in the family should know where the main switch is so it can be pulled in case of accidents, fire, flood, or windstorm damage.

_Fuses and Circuit Breakers_--These are the safety valves of your electrical system. The different electrical circuits in your home are meant to carry only certain amounts of electricity. Some carry only 15 amps, others can carry 20 or more. They are marked to show capacity.

When a fuse burns out or a circuit breaker opens, look for an overload of lights and appliances on the circuit before you try to replace the fuse or close the circuit breaker. Without these safeguards, the overloaded electric line will heat up and may start a fire. Even if no fire starts, electricity will be wasted and the homeowner will be paying for electricity that's doing no good.

Remember: If you ever have to replace a fuse, pull the main switch first. Keep a flashlight handy in your house. It seems that fuses usually blow at night, and it doesn't pay to stumble or fumble around electric wires in the dark.

WHAT TO DO: Make A Circuit Board

So that you can show others how electricity travels from here to there, and how it behaves under different conditions, make an electric circuit board.

_Materials Needed:_

Piece of 3/4" board about 4" x 6" l-l/2-volt No. 6 dry cell battery Two pieces of bell wire, each 24" long, one black, one white Two 10-penny box nails (3") Three 3-penny box nails (1") Two small screws or carpet tacks Two 2-inch rubber bands Two miniature sockets with solder terminals Two l-l/2-volt flashlight bulbs

_Tools Needed:_ Ruler, pencils, hammer, pliers or vise.

_Making the Board:_

1. Lay out the board with a pencil and ruler as indicated in Figure 1.

2. Bend the three-inch nail as shown in Figure 2, using pliers, vise and hammer.

3. Pound the one-inch nails into the board for a half-inch at points A, C, and D. Use the three-inch nail to make a hole a half-inch deep at B. Put the crank nail in this hole and pound in a little farther. Attach the lamp socket brackets at E and F. Stretch the rubber band as in Figure 3.

4. Lay out the electricity path, the circuit (Figure 3). Use the black wire for the positive side of the circuit (the center pole of battery). Twist it around the switch crank B, and the center pole of battery. Run another piece to the outside terminal of bulb socket at E. Run white piece to negative pole of battery from the other terminal at E.

5. Close the switch. The rubber band should hold the switch nail tightly against nail at C. Does the bulb light? __________ If it doesn't, check the connections.

Now you have a circuit--a closed circuit when the electricity runs all the way from the positive pole to the negative pole. The black wire is the hot side, the live wire, because it carries the full load of the battery up to the bulb.

Remember, battery current is direct current, DC. In the case of alternating current, AC, such as most homes and buildings use, the electricity flows in first one direction and then the other.

Parallel Wiring

To make this circuit hookup, attach another white wire to the negative pole of battery and a terminal of the second flashlight bulb. Run a black wire from the other terminal to the switch terminal at C (Figure 4). Close switch. Both bulbs will light.

Trace the circuit. Electricity is going equally to each bulb, the same amount that went to the single bulb. The difference is that the battery will last only half as long. It's like a pail of water with two open spigots. The pail empties twice as fast as it would with just one spigot open. This type of wiring is called parallel wiring. If one bulb is unscrewed, the other will stay lit.

[Figure 4 (Parallel Wiring)]

Series Wiring

To do this, run the negative wire to one terminal of the second bulb and attach a wire from the other terminal to a terminal of the first bulb. The other terminal connects with the switch at C (Figure 5). This is series wiring. If one bulb is unscrewed, the other will fail to light because the circuit is broken for both. Anything that breaks the circuit has the effect of opening the switch.

Show there is a circuit through the bulb by screwing and unscrewing it. Also, "jump" the socket by running the wire from C to the other terminal of the bulb at E while it is unscrewed. Bulb at F will light. Trace this circuit.

SUGGESTED DEMONSTRATIONS

Using the Circuit Board, you can give many demonstrations of the way electricity flows, works and behaves.

Water And Electricity

To help others understand electricity better, draw a water system on an electric circuit board paralleling the circuit. For the battery show a water tank, pipes instead of wires, faucets instead of switches. Somewhere on the board paste a comparison of electrical terms with terms used in describing water, such as the following:

Wire equals Pipe Volts equal Pressure Amperes equal Rate of Flow - gallons per second Watts equal Pressure times Rate of Flow Switch equals Faucet Current equals Flowing Water

Show how to figure the wattage that a circuit protected by a 15 ampere fuse can handle. Do it with actual things or cut-out pictures of light bulbs, irons, toasters, coffee-makers, etc.

You know that Amperes times Volts equal Watts. If the voltage is 115, a 15 amp circuit can handle 115 volts times 15 amps, or 1725 watts.

The name plates on electric motors indicate the amperage at full load. You can convert this to watts, of course, by multiplying amperage by the line voltage. Motors require an additional amount of electricity when they start. You need to allow for this fact, so fuses will not blow or circuits trip when a motor is turned on. You will learn more about this when you study electric motors.

For More Information

Your leader has many other sources of information about electricity and demonstrations you can perform. Ask him. Also, libraries have many books about electricity and its history, which are very interesting and useful. Maybe you can find an electrician, someone from your power supplier, or an equipment dealer who will talk to your club on electricity or electrical safety.

What Did You Learn?

(Underline the correct answers then discuss in the group.)

1. In a water pipe system water flows. In an electrical circuit (electrons) (atoms) (charges) flow.

2. Electricity or electrons flow (easier) (harder) (about the same) in a conductor than in an insulator.

3. Rubber is a good (conductor) (insulator) (ground).

4. The most common material used as an electrical conductor is (glass) (silver) (copper).

5. The unit of electrical pressure or push is the (ampere) (volt) (watt).

6. The rate of flow of electricity is measured in (gallons) (amperes per minute) (amperes).

7. Volts times amperes equals (watts) (kilowatt hours) (alternating current).

8. A dry cell battery (stores) (makes) (uses) electrical energy.

9. In a parallel circuit the electricity has (one) (two or more) (no) paths to travel.

10. In a series circuit with two bulbs and a switch the bulbs are (brighter) (dimmer) (the same) as when they were in the parallel circuit.

LESSON NO. B-2

Credit Points 4

TOOLS FOR ELECTRICIANS

Who goeth a borrowing Goeth a sorrowing Few lend (but fools) Their working tools

Tusser 1524-1580

Whenever a job comes up, it saves time and trouble when you have the right tools and they are all where you can find them. Electrical work takes some special tools and some everyday tools.

If you have ever watched a good electrician at work, you've seen how neatly he stores his tools in a box so every one of them is handy. When a lineman climbs a pole, he has his regular tools in a holster on his belt. Special tools are kept in a box in racks in the repair truck, all ready for instant use. Wouldn't you like to have electrician's tools all handy, ready for use, and know how to use them properly?

Basic Tools for Electrical Work

_Knife_

A good knife with a sharp blade is one of the most useful tools. A camper's or electrician's type knife is probably best because it has other useful parts besides the cutting blades--a screwdriver or punch, for instance. Of course, you'll never use the cutting blades as a screwdriver. This knife should be kept clean, dry, sharp, and free from rust. Put a little oil on the joints from time to time. Remember, "Never whittle toward you and you'll never cut yourself."

_Pliers_

A pair of electrician's pliers should be part of your kit. Wrap the handles with plastic insulating tape. Even though you're not going to work on "hot" electric lines, it pays to play safe. Later on, as you learn more about electricity, you'll want a pair of needle-nose pliers for the fine work.

_Screwdrivers_

You'll want a screwdriver which has true corners. A 4 to 6 inch plastic handled screwdriver with a narrow blade is best. You'll probably need more than one size to fit the various size screws you'll be turning.

Screwdrivers are easily damaged if you try to use them as chisels and pry bars, or use them in screw slots which are too large for the blade.

You can be hurt by the screwdriver if you try to screw or unscrew things you are holding in your hand. Keep your free hand away from the end of the screwdriver. Place the work on a bench or where it can be handled easily.

_Soldering Iron_

A good 100 to 250-watt electric soldering iron will be useful. Later on you may want to buy a soldering gun, but unless you are doing a lot of soldering it won't be necessary. A supply of resin-core electrician's solder will be needed. Acid-core solder reacts with copper and in time causes a bad splice.

_Tape_

Once it was necessary to use two types of tape on splices--rubber tape with friction tape over it. Now there is a plastic tape on the market which takes the place of both and has good insulating quality. It is called electrical tape, or plastic tape, and resists water, oils (which would damage rubber tape), and acids. You'll need a lot of tape in your electrical work, so keep a roll on hand.

_Other Tools and Equipment_

As you go along in electrical work, you'll be adding tools and other equipment, such as a trouble light and maybe an ammeter or voltmeter. Other tools you'll want to add will be a Phillips screwdriver, open end wrenches, a crescent wrench, small hack saw, hand drill and bits.

You'll also be using some regular carpenter's tools such as hammers, saws, and so on. Unless you use them frequently, you don't need to keep them in your electrical kit.

It's a good idea to start acquiring a supply of electrical parts--lengths of wire, fuses, switches, sockets, plugs, and other items that will come in handy. There are parts you can salvage from old lamps, motors, and other equipment. Such a collection can be a real treasure chest when you need a part in a hurry. But be sure to throw away all faulty parts.

WHAT TO DO: Build a Tool Chest

To keep your tools always ready for use, a tool chest will be very handy. It's the 4-H way to work. You'll be surprised how much easier it makes a job when you have your tools, various parts and repair equipment all in one place. You can make the chest (Figure 1) with a saw, plane, screwdriver, pencil, ruler or carpenter's square, and hammer.

_Materials You'll Need:_

A piece of lumber 1" by 10" by 8 feet long. (1" lumber is actually only 3/4" thick--this is the thickness you'll be working with.)

2 small hinges, with wood screws

1 small hasp, with wood screws

2 small handles with wood screws, or one large handle

1 small chain, 10" to 12" long

Some No. 6 penny finishing nails or wood screws about the same length

_Making The Chest:_

1. Cut your lumber into the following pieces:

1 piece 10" x 18" for top

1 piece 8-1/2" x 16-1/2" for bottom

2 pieces 6" x 8-1/2" for two ends

2 pieces 6" x 18" for front and back

2. Lay out pieces as shown in Figure 2.

Then, set up the two end pieces and nail to bottom section. Refer back to Figure 1 as you go along to see that box is shaping up as shown. Nail the front and back sections to the ends along the bottom. Wood screws can be used instead of nails.

3. Lay the top in place and attach hinges to the back side, about two inches in from each end.

4. Attach one part of hasp to the top, and the other part to front board in center. Fasten the handles to each end.

5. Attach chain to the top and front so the top will stay open when chain is fully extended.

Now you can invent your own improvements for your chest. You can paint it, put your name on it, and your club emblem and name if you wish. You can put a rack on the inside of the cover to hold your work sheets and other booklets and materials. You can install special slots or straps to hold each tool in its place along the sides of the box. Maybe you will want to put some partitions in the box to separate various electrical equipment such as wires, fuses, switches, and plugs.

_A Working Kit_

An accessory which you may want to add to your tool chest is an apron or holster to wear when you are moving around on the job. An apron can be made of a size of cloth about 18 by 20 inches. It should be folded up from the bottom, and sewn to fit the number and size of tools you have. Figure 3 shows such an apron.

You can make a lineman's holster in the same way, using plastic or soft leather. Merely make belt loops by cutting on the dotted lines. A snap fastener will hold the flap over the tools so they won't fall out.

Demonstrations You Can Give

Show and tell others the proper handling, care and use of tools.

Show and tell how to build an electrician's tool kit.

For Further Information

Ask your power supplier or an electrician to tell the club about the various tools of the electrician's trade and demonstrate them. Ask your leader how to get exhibit material or information about electrical tools and their use and then tell the club about them.

LESSON NO. B-3

Credit Points 3

REWIRE A LAMP--BE A LAMP DETECTIVE