ELECTRICITY AROUND THE FARM AND HOME Requirements for

ELECTRICITY AROUND THE FARM AND HOME Requirements for
E. M. 2351
ELECTRICITY AROUND THE FARM AND HOME
Requirements for Unit II
1.
2.
3.
4.
Review Unit I
Complete the 7 Lessons
Build an elect~ic motor - see Lesson 6
Give at least one demonstration
Lessons - After studing the lesson, answer the review questions and complete
at least one activity for each lesson. Follow the activity outline
shown in the lessons. You do not need to complete other activities
listed on the guide sheets.
1.
2.
3.
4.
5.
6.
7.
Reading the Electric Meter
Give Your Appliances A Square Meal
The Electric Iron - Your Personal Servant
Conv~nient Controls for Light
Live with Light - Outdoors
What Makes Motors Run
Taking Care of Electric Motors
Exhibit - Assemble and exhibit at least one item which indicates some phaseof
the electric project on which you have worked this year.
Demonstration - Give at least one electrical demonstration during the year.
It may be given at a 4-H club meeting, an Area meeting,
other community meeting or at a fair.
This material was organized and prepared by Sam Doran, Grant County
EXtension Agent, and Ken Crow,
Ephrat~.
E·.'M. 2351
LESSON NO. 1 READING THE ELECTRIC METER
A.
Page 2
Learning to Read an Electric Meter.
Nearly every farm and home has electricity today. In order to know how much
electricity is used by each farm and home, electric utility companies install
electric meters. Once each month the meters are read to find out how much
electricity was used during the month.
There are different kinds of electric meters. All of them show the kilowatthours of electricity used. In this lesson you will learn about some of the
different kinds of electrical meters and how to read them.
After you have learned to read the different kinds of electric meters shown
in the lesson, you can determine the electrical cost of operating lights, electric appliances, motors and other items which use electricity.
B.
Review:
To be sure you understand the proper meaning of the electrical terms used in
this lesson, write the meaning of the following terms. Ask your leader or
parent to check your answers.
Watt
Kilowatt
Kilowatt-hour
Demand meter
C.
Activity: Complete either of the following activities.
1. Estimating the electrical cost of operating appliances, etc.
Following the procedure shown on pages 2 and 3, determine the monthly
electrical cost of operating at least three electrical items around your
home or farm. Record the information on Chart 1, on page 4. Include
such items as hot water tank, refrigerator, toaster, floor lamp, radio,
electric motor, etc. Use the Electrical Rate Schedule shown in chart two,
page 4.
2.
D.
Reading the Electric Meter.
Read the electric meter for your home once a day for one month. Read the
meter the same time each day. Make a chart showing the amount of
electricity used each day during the month. Using the cost schedule
on page 4, estimate the daily cost of electricity.
Demonstrations:
1. Make a display to show how to read an electric meter and how to determine
the kilowatt-hours of electricity used since the last reading.
2. Show, on a chart, the electrical cost of operating various items found
around the home or farm.
3. Show the amount of electricity a home will normally use in one year and
how much electricity is needed for various electrical items.
4-H ELECTRIC GUIDE SHEET
10
1ft READING THE ELECTRIC
•
7
METOER'N-E-4·B_·-
here is no question but what electricity
is one of the lowest cost services in
T
the home and on the farm. A few pennies
worth of electricity will provide the power to
run machines that take the place of a man or
of several men working all day. However, we
all like to know what things cost.
Sometime you may have to decide between
different methods- man, horse, gasoline engine or electric motor power. Then you'll
want to know how to figure the cost of electricity, as well as the cost of the original
equipment. First of all, you should know
how to read an electric meter.
Reading a Meter
Electric meters read in kilowatt hours, just
as a water meter reads in gallons and a gas
meter in cubic feet. A kilowatt hour is the
electrical energy consumed by 1000 watts of
electricity used for one hour. Ten 1 00-watt
light bulbs burning for one hour would use
one kilowatt-hour -- one kwh.
€)
IIILOWATT
a
HOUIIS
kwh; the third, to 1000 kwh; the fourth, to
10,000 kwh. After that, the meter starts over
again. To take a reading you must read all
four dials of the meter, from right to left.
KILOWAT T
HOURS
a
Figure 1. Some meters give the reading directly, like
the mileage total on a speedometer.
Some meters are read directly, as shown
in Figure 1. The more common type has four
dials which are read from right to left - just
the opposite from the way things are usually
read. The hand on the extreme right turns
clockwise, the next hand turns counterclockwise, the next clockwise; the last hand on
the left turns counterclockwise.
The first dial on the right can register
up to 10 kilowatt-hours; the second up to 100
Figure 2. Meter dials are read from right to left.
To read each dial, you use the number
last passed by the dial hand. This may not be
nearest the hand. For instance, if the pointer
has passed 6 and is almost on 7, you read it
as 6. Write down the figures in the same
order you read the dial, from right to left.
Practice reading the meters shown in Figure
3 on the following page.
What's Your Electric Bill?
Meters aren't set back each month when
the meter reader comes around. The differ-
-2-
OUTLINE 4·8·7
Estimating Operating Costs
To find the cost of operating any single
appUance, three steps are necessary:
le Learn the wattage of
th~
appliance.
2. Estimate how many hours the appliance
is used.
3. Find its operating
cost~~
To Find Wattage:
Figure 3. See if you can read the above correctly.
The answers ore shown in a box on the next page.
ence in the readings from ont:. month to the
next shows how many kilowatt-hours have
been used. If you know your electric rates,
you can figure your bill by yourself. Your
power supplier will furnish you with a rate
schedule on request.
It will be interesting to you to find out
how much it costs to operate the various
electric appliances in your home. A sample
rate schedule is shown in Figure 4.
Demand Charge
$2.10 per kilowatt.
In lieu of a demand charge, customers
without demand .meters pay one cent per
kwhr in addition to the net energy charge
(See Rate 6) .
Kwhrs
Net Energy Charge
4.45¢
per kwhr for the first . . . . .
50
3.25¢
per kwhr for the next . . . • . 450
2.65¢
per kwhr for the next . . . . . 2000
2.25¢
per kwhr for all over ..... 2500
The gross energy charge is 10o/o more
than the sum of the net energy charge and
the fuel adjustment.
inimum Charge: $1.00 net
onth.
Watts, you know, are the measure of
electrical power. They are the product of
voltage (pressure) times amperes (rate of
flow). Volts times Amps equals Watts. The
nameplate on the appliance will give the voltage required for proper operation as well as
either amperage or watts. If it gives wattage,
you have the information you want. Otherwise you must multiply volts times amps to
get the wattage. When voltage is given as
110-120, use 120 as your voltage. 120 volts
is nominal today.
How Much Will You Use?
Now that you know the wattage of the appliance, multiply this figure by number of
hours the equipment operates in one day.
Divide this by 1000 to get thekwh. Now multiply the result by the number of days the
appliance is used each month. This tells you
the number of kwh used by the appliance during the month.
Yard Light:
Example No. 1
300-watt lamp
Amount of use: 3 hours per night.
Multiply lamp wattage times hours of use
per night to get watt-hours per night.
300 times 3 = 900 watt-hours per night.
Divide watt-hours by 1000 to get kwh per
night.
900 divided by 1000 = .9 kwh per night.
Multiply kwh per night times 30 to get kwh
per month •
•9 times 30
Figure 4. Sample rate schedule. Note that as the use
of electricity increases, the average cost per kwh is
reduced.
=27 kwh per month.
If the yard light is used 3 hours per night,
it consumes 27 kwh per month.
- 3-
Adding Low Cost Helpers
Example No. 2
Coffee Maker: 120 volts, 550 watts (from
nameplate)
Amount of use:
OUTLINE 4·8·7
1/2 hour per day.
Multiply wattage of coffee maker times
hours of use per day to get watt-hours per
day.
550 times 1/2 hour= 275watt-hoursper
day.
Divide watt-hours by 1000 to get kwh per
day.
275 divided by 1000 = .275 kwh per day.
Multiply kwh per day times 30 to get kwh
per month.
.275 times 30 = 7.250 kwh per month.
If the coffee maker is used 1/2 hour daily,
You can see, by looking at your rate schedule, that the average cost per kwh gets lower as you use more electricity. To find the
cost of operating additional electrical equipment, the cost per kilowatt hour is found from
the last "step'' in the bill - the lowest cost
per kwh of the electricity you're now using.
Sometimes power suppliers give special rates
for such equipment as electric water heaters.
WHAT TO DO: Find the Cost
·of Operating Electrical Equipment
Make and fill in the blanks of a chart
showing the electrical equipment you have
and the operating costs per month.
it consumes 7.25 kwh per month.
Calculate Operating Cost Per Month
Now that you know the number of kilowatt
hours an appliance uses, go to your rate
schedule and your electric bill to see what the
average kwh costs. Find the average cost of
1 kwh by dividing the amount of your bill by
the total number of kwh used in a month.
'E:xample: 410 kwh used.
$14.35 total monthly bill
Average cost per kwh equals $14.35divided
by 410 kwh - 3-1/2 cents per kwh.
Therefore, the cost of operating the coffee
maker for a month would be 3-1/2 cents
times 7.25 kwh - 25.4 or 25 cents. Cost of
operating the yard light would have been 94.5
or 95 cents a month.
Make a chart for the home (refer to chart
one). Show the probable operating cost of
equipment you might add to what you now
have.
Demonstrations You Can Give
Show how to read a meter, making one
with plywood or cardboard. Dials can be
painted on the main board. Arrows can be
attached so they will revolve to give different readings.
Show how to find the wattage of various
types of equipment.
Show how to figure the cost of the average
kwh in a home.
For Further Informa tion
(a) 6357
(b) 1963
(c) 8996
Correct answers to the meter readings
shown on the preceding page.
Your leader can get additional material
for you or you may want to have someone
from your power supplier talk to your club,
telling about meters, how they work and how
they are regularly checked for accuracy.
E.M. 2351
Page J
Chart One - THE HOME
Column No.
1.
Wattage
Rating
Item
2.
Hours Used
per Month
J.
KWH per Month
(col. lx2)
1000
4~,
Cost per Month
(Col. 3 x av. kwh Remarks
cost)
Electric Iron
Chart Two - ELECTRICAL RATE SCHEDULE - MONTHLY BASIS
Applicable to all domestic ;· light, heat and power consumers for single
phase service to a single private residence, individual family or
general farm use.
Energy Charge:
3.5t per kwh for the first
2.5t per kwh for the next
l.Ot per kwh for the next
0.5¢ per kwh for the next
0.75¢ per kwh for all additional kwh
50
50
200
400
kwh
kwh
kwh
kwh
E.M. 2351
Page 4
LESSON NO. 2
A.
GIVE YOUR APPLIANCES .AND LIGHTS A SQUARE MEAL
Electrical Appliances Improve Our Life
Electrical appliances ease our work and make our living more enjoyable.
People .keep buying more electrical appliances for their home and farm. When
they add more appliances the wiring may be inadequate to handle the additional current required. When that happens the voltage is reduced below
normal and the appliances do not function properly. As you study this lesson
you will learn to recognize the symptoms of inadequate wiring in the horne and
how to correct the situation.
You should review Lessons 5 and 6 in Unit I before you start making the
circuit chart outlined in the activity for this lesson.
B.
Review: Answer questions on page 4.
answers.
C.
Activity: Complete either of the following activities. Read the Electrical
Safety Notes below before you start this activity.
1. Make an Electrical Circuit Chart. Starting at the main fuse box, make a
drawing that shows the electrical circuits in your home.
a. Show the rating of the main fuse.
b. Show the number of circuits in your home.
c. Show the number of outlets or lights on each circuit (These can be
traced with a test lamp or trouble light).
d. Show the wire size, fuse size .and amps of electricity each circuit
will need when the usual lights or outlets on that circuit are in use.
(See Lesson 1 in Unit I to determine amperes used by each outlet and
lamp.
2.
Have your leader or parent check your
Electrical Wiring in a New Horne. If you wish to do another activity
for this lesson, as.k an electrician or electrical contractor to take you
to a home being constructed so you can see how a new house is wired.
After you have examined the wiring, make a diagram showing how the house
is wired. Follow the outline above for Activity No. 1.
ELECTRICAL SAFETY NOTES:
1. Never work on electrical circuits when you are alone. Have a parent or
your leader with you when you check the electrical outlets.
2. Do not work on "live" electrical circuits. Experienced electricians
will not work on electrical circuits -unless the fuse has been removed.
Follow their example. Turn off each circuit while you ·c heck it.
3. Do not deliberately overload any electrical circuit.
D.
Demonstrations:
1.
2.
3.
Show and explain what happens when a circuit is overloaded.
Show and explain what can happen when a circuit is fused for more or
less than the capacity of the wire.
Show and explain what problems can arise as the number of appliances in
a home are increased.
4-H ELECTRIC GUIDE SHEET
•
I. . Give your appliances and lights a~~~~;; meal
0
Shrinking TV picture
Heating appliances slow
ould you say that having enough to eat
W
was pretty important in the home that
you know?
The "food" for your appliances and lights
is electricity, and like you they must be
"fed" enough.
What to Do
1. List the appliances and lights in your
home.
2. See if any of them are "starving" for
the electricity they need.
3. Learn how the electricity gets to where
it's used.
4. Make a chart of the electrical circuits in your home.
14
Too much fuse blowing
lights dimming
5. Make sure that each circuit is pro tected with the right fuse or circuit breaker .
Count Your Electrical Blessings
Many people in much of the rest of the
world wish that they could trade places w1th
us, because we have so many electrical appliances in our homes.
Of course, we have not always had as
many appliances as there are today. When
electricity first came along, people used it
only for lights.
Then, they began to add
flatirons , washing machines, refrigerators,
coffee percolators, a nd radios.
Then more and more electrical things
were made for people to use and enjoy. Now
we have dozens and dozens of uses for elec tricity in our homes.
-2-
How many different uses for electricity
are there in your home today? Ask your
parents how many there were when your
home was built or first wired. How many
were common when your parents began to
keep house?
Some Homes Are Behind Times
Many older homes were built before electricity was available, and were wired later.
And like them, some older homes that were
wired as they were built had only enough
wiring for lights and a few other appliances,
because those were the only uses that were
known at that time.
OUTLINE 2-B-14
Here are some things you can watch for
in your own home. They will tell you whether
your appliances are getting enough electrical "food" or not.
1. A shrinking TV picture--If it draws
in from the sides of the screen, fades, loses
contrast, or if the sound becomes distorted,
you may have low voltage.
2. Too much fuse blowing or circuit
breaker tripping.
3. Heating appliances are slow to do their
jobs.
4. Lights dimming, when motors or other
appliances are turned on.
There Should Be Enough Ways
to Get "Appliance-Food" Around
H appliances in your home show these
starvation signs, then you may not have
enough ways for the electricity to get to
where it's used.
But people kept on living in these homes,
and kept adding to the uses they made of
electricity without adding to their wiring.
What has this meant? Well, if electricity
were like cars and trucks, you could say
that some people are trying to put turnpike
traffic through a back-country dirt road!
Watch for Signs of Starvation
Of course, as your state has done with its
highways, some people have expanded and
modernized their wiring. But many others
have not yet seen this need, or if they have,
they may have to do it again.
Here's why:
Your power supplier delivers current to
you at the right voltage or electrical pressure. H the wires in your house are large
enough, they will pass this full voltage on to
the appliances.
But if your wiring is too small, the electricity arrives at the appliances so weak
that they can't work properly, and much of
what you pay for is wasted.
There are three kinds of these electrical
highways or circuits, and your home should
have enough of each:
1. General purpose circuits --These
serve lights all over the house, and convenience outlets everywhere except in the
kitchen, laundry, and dining areas.
A rule-of -thumb is: There should be at
least one general purpose circuit for each
500 sq. ft. of floor space.
2. Small appliance circuits--These are
not used for lights, but instead they supply
convenience outlets in the kitchen, laundry,
and dining areas where portable appliances
are most used.
Every home should have at least two
small-appliance circuits.
3. Individual or special-purpose circuits
--One of these is needed for each: electric
range, dishwasher, water heater, freezer,
automatic washer, clothes dryer, air conditioner, pump, and house heating equipment.
OUTLINE 2-B-14
-3-
Ill
I
j
.
•
•
•
Gauge
Size
•
14
12
10
8
6
Fuse or
Breaker
15
20
30
40
55
Max . Watts
at 115 V.
1725
2300
3450
4600
6325
Max . Watts
at 230 V.
3450
Actual
S~e
4600
6900
9200
12750
Wire sizes commonly used in homes
A policeman uses his brain to tell him
when to blow his whistle, but a fuse depends
on the size of the little fusible (meltable)
metal link that you see under the glass .
If too great an electrical load is added to
a circuit, this link will melt and prevent a
dangerous overload. If you put in a fuse
with too heavy a link, it will not melt in
time, and the wiring and equipment may be
damaged.
Therefore the right size of fuse is very
important, and is something that you should
check in your own home.
See the chart above for the right fuse for
each size wire.
Each Circuit Big Enough
The capacity of each circuit is limited by
the size of its wires. The chart above shows
you the actual sizes of wires commonly used
in permanent home wiring, and what each
will carry. Notice that each size is given a
number, and the smaller the number, the
bigger the wire.
Also notice that a given size of wire will
carry twice as many watts at 230 volts as it
will at 115 volts. (Watts are figured by
multiplying amps times volts. )
General purpose circuits usually are
either Number 14 or Number 12 wire, at
115 volts. What is the capacity of each, in
watts? (Number 12 wire is recommended
for all new general purpose circuits. )
Make a Circuit Chart
At one or more places in your home there
is a box or panel containing the fuses or
breakers for the various circuits. Attached
to the inside of the door of each such panel
should be a chart something like this:
-no:
1
t
~~
ff~
40
~
~~
j.-0
3
Lf~~~
'20
4-
~~t1lt:aPdv
/5
Small appliance circuits are required to
be at least Number 12 wire.
Individual circuits are always sized according to the appliance they serve. Find
the size wire that should be used for a
10, 000-watt, 230-volt range; a 1500-watt,
115-volt dishwasher; a 4500-watt, 230-volt
clothes dryer.
Only One Fuse Size Right
A fuse in an electrical circuit is like an
alert traffic policeman--stopping everything
if there's danger. A circuit breaker serves
the same purpose, and the right size is installed when the wiring is done.
~
-
-
--
-
---~
Notice that in our chart we have made
columns for a description of what each circuit serves, its number or position in the
panel, and the proper size fuse for it.
Because most such charts leave out this
last very important bit of information, you
should make a complete new chart, like the
one shown. Provide as many lines as there
are fuse positions. Paste or tape it to the
inside of the panel door.
-4Then, ask permission of your parents to
disconnect all the circuits by unscrewing the
fuses or flipping the circuit breakers. Do
Then
not touch anything but the fuse rim.
reconnect them, one at a time, to find out
what each circuit serves. Turn on as many
lights as you can, to help you in your detective work. Use a test lamp at those outlets that do not have a light connected to
them. Write two or three words describing
each circuit on the proper line on your chart.
On a separate sheet, keep track of the
appliances and lights that are on each circuit, and add up the watts. (If the nameplate of any appliance gives "amperes",
"amps", or "A" instead of watts, just re member that amps times volts equals watts. )
This will tell you if any of them are overloaded. Show this sheet to your parents.
Check the Wire Sizes
Disconnect the main switch, and determine the size of the wires in each circuit.
Don't include the insulation in your measurement.
BE CAREFUL!
OUTLINE 2-B-14
over with your parents. They may want to
ask an electrician to go over the wiring and
make the necessary changes.
What Did You Learn?
(Underline the right answer.)
1. A (television set, radio) is very sensitive to changes in voltage.
2. Dimming lights mean (static in the
wires, an electrical overload).
3. Wires that become warm from overload make it (more expensive, cheaper) to
operate the equipment.
4. A home of 2, 000 sq. ft. should have
at least (three, four) general purpose circuits.
5. One solution to low voltage symptoms
is (heavier fuses, more circuits).
6. Full capacity for a Number 14 wire
circuit at 115 volts is (1725 watts, 3000
watts).
.E ven though yot1 have dtk!onneatea'
the main gwit:ciJ/ the wti'es conJing
7. A room air conditioner should be on
(a general purpose, an individual) circuit.
li?(o It are still nile~~ 8~ c/o not CO(.Ic/7
any wt~s. ln~teact hold #Je wtre size
8. The purpose of a fuse is to (let you
disconnect the circuit, automatically prevent overloading the circuit).
ciJart near them eo tnat yo(/ can tell
whla.h gavge eaah one ls.
Write in the proper size fuse for each
circuit on your chart.
Replace Any Wrong-Size Fuses
Do the fuse sizes you have written on your
chart agree with the ones that are in place
in the pane 1 ?
9. The right size fuse is determined by
(wire size, the store where you buy it).
10. A circuit chart should give (circuit
description and fuse size, the maker's
name).
Demonstrations You Can Give
Get the right size fuses and replace any
that are wrong. Make sure that you have a
reserve supply of the right sizes, and that
they are handy for future use.
Ask your leader to help you plan a demonstration. You can show how lights dim
when too many other appliances are connected, how a fuse protects against overloading, and the danger of using too large a
fuse.
Talk it Over With Your Parents
For More Information
Do you think that your home has enough
of the proper size circuits? If not, talk it
Ask your Extension agent, power supplier , or electrician for additional help.
E.M. 2351
Page 5
LESSON NO. 3
THE ELECTRIC IRON - Your Personal Servant.
A.
The Electric Iron - a Common Appliance
One of the most common electric al appliances around the home is the iron.
NearlY every home has one. The things you learn about irons in this lesson
will help you understand how many other appliances work for you. After
reading the lesson carefully, study the picture on page 4 which shows a
typical modern steam iron. Be sure you understand the purpose of each part
of the iron.
B.
Review: Answer the following questions. They will determine what you have
l earned about the operation and care of an electric iron. Have your leader
or parent check your answers.
1. Answer the questions on page 3.
2.
Where is the heating element in an iron?
3.
How is the steam formed in a steam iron?
4. What is the function of a thermostat:
5.
How many watts does your electrical iron require?
6.
Why is the handle of an iron made of plastic?
C. . Activity: Visit an Ele_ctrical Appliance Store.
Invite another electric project memoer to go with you. If you arrange
ahead of time to visit the store when the clerks are not too busy, they
usually will be glad to help you compare some different types of appliances.
Compare two or three irons, electric frying pans, or other appliances of
different prices. Look for differences in construction and operation of
two or three appliances, such as irons, frying pans, electric clocks, toasters,
etc. Write a report of your visit. Indicate the items you compared and the
differences you observed, on chart on the next page.
D.
Demonstrations:
1. Show the proper use and care of an electrical appliance.
2.
Demonstrate the effect of high or low voltage on an electrical
appliance.
EoM. 2351
Page 6
GUIDE FOR COMPARING ELECTRI C APPLIANCES
Type of
Appliance
Model
Number
Kind of
Warranty &
Free Service
Period
Sales
Price
Important Value Features
(Time, work or money
savers, or features that
increase usability)
4-H ELECTRIC GUIDE SHEET
OUTLINE 4-S-1
THE ELECTRIC IRON
YOUR PERSONAL SERVANT
M
ost girls are going to do a lot of ironing as teenagers and later on as housewives too. Boys will also find there are
many times when they will need some knowledge about ironing, especially how to press
their trousers. If you learn now how to
iron and press efficiently, it will save a lot
of time for other things and make the ironing chore go much easier. The iron is
your personal servant, but it's up to you to
be sure it does its work correctly. You
should also know how to select the iron
that will do the job best for you, and will
give you the longest service.
Selecting the Iron
For home use there is the automatic
dry iron, the automatic steam iron and the
combination steam-and-dry iron. For
travel there is a smaller iron, but it is not
so efficient for regular use. Some travel
irons will operate on either AC or DC current.
The control for changing from steam to dry
and for cutting off steam should be easy
and convenient to operate.
The important points in selecting an
iron are:
Tips On Ironing
1. You should consider the ironing and
pressing jobs you will do most often.
2. Remember that lightweight irons,
from 2-1/2 to 4 pounds, are preferred.
Heat, not weight, does the job in ironing.
3. The temperature control should be
easy to read, to set, and should indicate
the setting for different kinds of fabrics.
4. The sole plate should be smooth,
well-polished, and should heat evenly.
5. Beveled edges and button ledges are
convenient for ironing around buttons.
6. A narrow, pointed nose is helpful
in ironing pleats, gathers, and corners.
7. The handle should fit your hand
comfortably and stay cool.
8. The cord should be reinforced at the
end nearest the iron.
9. Steam irons should be easy to fill
and should hold at least one cup of water.
1. Use a convenient outlet to plug in
your iron.
Never use a drop cord or
lighting outlet - the wires are not large
enough to carry the electrical load.
If you have to use an extension cor d, be
sure the wires are asbestos insulated and at
least No. 16, and that the iron cord and the
extension together are not over 10 feet long.
If the wires are too small or the cord too
long, you will waste electricity and your
iron will not operate properly due to the
electrical resistance in the wire.
2. Set the temperature control for the
fabric you are going to iron or press. The
thermostat will shut off the electricity when
the iron reaches the proper temperature
and will turn it on again as soon as the iron
-2-
(
starts to cool. The thermostat is the heart
of the automatic iron. It maintains the
temperature that you have selected, automatically.
OUTLINE 4-S-1
12. The job will be easier if you sit
while you iron.
Suggested Ironing Routines
Start ironing with fabrics requiring the
lowest temperature, such as dynel, dacron,
orlon and rayon. Finish with those needing
the higher temperatures (such as cotton)
because your iron will heat much faster ·
than it will cool.
Gathers and Straight Gathered Ruffles
1. Manipulate garment, or iron so that
point of iron works into fullness.
2. Use in-and-out strokes
3. Don't iron over top of gathers
4. Heavy cottons, linens, and starched
materials do best when sprinkled before
being dry-ironed. The steam iron is popular for wool fabrics that require light ironing and for steaming such materials as
corduroy and suede. In sewing, a steam
iron can be used to press each seam as
you go, which results in a professionallooking job.
5. When using a steam iron, follow the
manufacturer's instructions. Some manufacturers recommend the use of distilled
water.
Minerals in the tap water can
shorten the life of your iron. You may also
use clean rain or snow water.
6. Steam irons should be drained, and all
irons should be allowed to cool before
storing.
7. Never put your iron in water. You
can keep the sole plate clean by wiping it
when cool with a damp, soapy cloth. To
remove starch or stains let the iron cool
and rub off with a damp cloth or use a
moistened fine steel wool soap pad. Or
you may heat the iron slightly and glide it
back and forth over waxed paper.
Creased Slacks and Shorts
1. Lay one leg flat on board, underleg
side up, other leg folded back over top.
2. Fold so creases appear in center
front and center back of leg. Iron.
3. Turn over and iron outer leg up to
point where crotch begins.
4. Repeat with other leg. Finish top
over end of board. Note: Pajama pants,
play slacks and shorts are often ironed with
legs folded side to side. · Finish top over
end of board.
B. Iron around buttons and zippers- not
over them - to prevent scratching the sole
plate.
9. Be careful not to drop the iron. Store
it in a clean place where it cannot fall.
A Man's Shirt
10. Keep the cord in good condition.
Disconnect it from the outlet by pulling on
the plug. Never pull on the cord and never
wrap it around a hot iron.
11. Be sure to disconnect and turn the
iron to "off" when leaving. it for even a
few minutes.
1. Iron cuffs first; inner surface first,
outer surface second.
2. Iron body of sleeve, cuff opening
side first.
3. Repeat on other sleeve.
4. Iron yoke. Slip one shoulder over
end of board. Iron from center of back to
OUTLINE 4--S-1
-3shoulder. Reverse and iron other side of
yoke.
5. Iron body of shirt beginning with one
front and continuing to other front (or iron
both fronts first if fabric is drying out
quickly).
6. Iron collar, under surface first, upper surface second, working iron inward
from edges.
7. Fold collar down and press over end
of board.
6. List four cases where a dry iron
should be used:
!.______________ 2. _________________
3. ______________ 4. _ _ _ _ _ _ ___
7. Explain how to protect a sole plate
and keep it clean.
B. Study cord repair and learn the type,
size and length of cord needed for your iron.
What Did You Learn?
Is it best to use tap water or distilled
water in your iron? ___________________
What is distilled water? _____________
What is a good substitute?_____________
Why is some tap water undesirable? ______
Should you start ironing with fabrics
requiring high or low temperature?_____
-----------Why?_______________
WHAT TO DO:
1. Visit a nearby appliance store. Compare irons, study prices, value, and compare your needs. Which type of iron would
you buy?_____________________________
2. Set up a good place to work or arrange an ironing center. List the important items needed in an ironing center:
3. For one month press or ironallyour
own clothes and those of another member
of your family. How many articles did you
iron1
How many did you
press?_______________________________
4. For one week, iron all the flat work
for your family. How many articles did
you iron?____________________________
5. List four cases where a steam iron
could be used to advantage:
1.
2. _________________
3. ______________ 4. _________________
If you are a slow ironer, should you set
the iron to a higher heat? Yes _ _ No __
Should you store the iron when it is
hot _ _ _ or cold ______
What is the device in your iron that
maintains proper temperature? _________
Ironing efficiency fs the result of the
weight of the iron. Yea.
No _ __
Ideas for Demonstrations and
Exhibits
Demonstrations
Demonstrate the proper use of dry and
steam irons on various materials.
Demonstrate what voltage drop will do
to your iron.
-4Show and explain the importance of a
proper outlet when using an iron.
OUTLINE 4-S..l
Exhibit garments ironed properly and
improperly.
Exhibit an ironing center.
Give tips in handling and resting an
electric iron.
Show and explain how to care for an iron
and cord.
Show how to polish and clean the sole
plate.
Exhibits
Exhibit different types of irons identified as to purpose and use.
For Further Information:
Ask your leader about other information
sources or write for a copy of The Electric
Iron, Buying, Use and Care, by McCordic
and Young, University of Wisconsin, Madison 6, Wisconsin.
A TYPICAL MODERN STEAM IRON
HEAT RESISTANT
PLASTIC HANDLE
I
RUBBER
SLEEVE
FILLER DIAL
INDICATOR
RESERVOIR
FILLER DIAL
(1. of 15 Vents)
STEAM
CHAMBER
COVER
AUTOMATIC
THERMOSTAT
CAST
ALUMINUM
SOLE PLATE
Basic principles of the steam iron are incorporated into each des ign,
although irons vary from make to make.
IDENTIFICATION
PLATE
E.M. 2351
Page 7
LESSON NO. 4 CONVENIENT CONTROLS FOR LIGHTS
A.
Light Controls
There are many different kinds of light controls. The two most common light
controls are the pull-chain type and the wall switch. However, there are
many other common electrical controls. In this lesson you will learn about
many different kinds of manually operated and automatic switches.
B.
Review:
Answer the questions on page 4. They will help you decide how well you understand the lesson. Ask your parent or leader to check your answers.
C.
Activity: T,ypes of Light Controls
Using the chart on page 4, list at least six different types of manual and
automatic light controls you find around your home and farm. Draw additional
lines below the chart as you need them. If you cannot find six types of
light controls ask your parents or leader to help you. If necessary, list
some you have seen at school, in stores or homes you visit. Hint: One type
of light control is installed on most refrigerators.
D.
Demonstrations:
See list of suggested demonstrations on page 4.
4-H ELECTRIC GUIDE SHEET
I
OUTLINE 3-1-16
CONVENIENT CONTROLS FOR LIGHTS
~
lames, first in the form of campfires,
and later in the form of torches, lanterns, lamps, and candles, were man's
early attempts to provide himself with other
than natural light.
r
Man's controls of these flame sources of
light were simple, but they were neither
convenient nor safe. Man had to be right at
the light source, with a fire-starter of some
kind, to "turn it on. " He could let it burn
out for lack of fuel, but mostly he also had
to be right at the light to "turn if off.''
Today, with electricity we have light that
we can turn on or off as frequently as needed,
whether near it or not. Or we can have it
turned on and off for us by one of the many
kinds of automatic devices, even if we are
miles away.
What to Do
1. Learn about the various kinds of light
controls, how they work, and where they
are used.
2. List the various kinds of light controls
that there are in your home or on your farm.
3. Inspect as many different kinds of
light controls as you can. Use the descriptions that follow as a checklist. If possible,
help your club leader bring some of these to
a club meeting so that you might better under stand how they work.
4. Show others how some of these controls work, and tell how they are used.
Why Do We Control Lights?
We could let our lights burn all the time,
but there are some very good reasons why
we don't. In the first place, it would be very
wasteful, both of electricity and of the bulbs
and fluorescent tubes.
In addition, there are many times when it
is desirable not to have lights burning. This
is true in our sleeping rooms, in theaters
and churches, and when lights are used in
connection with plants and animals.
-2 -
How Should We Do It?
Our first consideration in deciding how to
control a light should be safety. We should
never use a control which is unsafe, or
which forces us into an unsafe position in
order to operate it.
Next, we should try to get as much convenience as we can, without overspending
for wiring and equipment. And convenience
encourages economy in the use of electricity,
making it easier for us to turn lights off
when they're not needed.
OUTLINE 3-1-16
In many situations this is the best control
to have. You are there, you want light right
there, and you simply reach for the switch
and turn it on. A disadvantage is that you
can only control one light at a time.
/Insulating link
Convenience also helps us to be safe,
making it easier for us to turn on lights
where they will help prevent accidents, as
on a stairway.
Select the Right Control
There are many different kinds and variations of controls that can be used, and it's
important that you select the right one for
each light.
You should decide whether the light is to
be controlled at the lampholder or away from
it, whether manually or automatically, and
many other questions.
There is danger from shock where the
person could stand on moist earth or concrete or touch metal plumbing. In these
cases, a pull chain should be used, making
sure that there is an insulating link in the
chain.
Switches away from the Light
Many times we want to control a light
from a distance--from only a few inches up
to many feet away from it.
This can be done in a variety of ways, but
the most common is to install a wall switch
at the desired control point. In this case
the light can either be wired in permanently,
or it can be plugged into an outlet that is
controlled by the switch.
[J
One important need on many manuallyoperated switches remote from the light is
for some kind of a plainly visible indicator-a pilot light or other signal that tells whether
the out -of- sight light is on or off.
Switches at the Light
Most of our portable lamps, and many of
our wired-in ones have switches built right
into them- -usually at or near the sockets.
These are the push-through, key (turn), pull
chain, or push- button types.
Most wall switches are of the tumbler or
snap type, for a quick make-and-break of
the connection.
This helps to eliminate
"arcing" or flashing over of the current.
Mercury switches are sometimes used
because they are quiet and long-lasting.
They have two contacts sealed into a small
glass tube containing a few drops of mercury.
When the glass tube is tipped, the mercury
flows to the end containing the contacts, and
closes the circuit. Tip it back, and it opens.
Any wall switch can be secured with a
built-in pilot light, or one can be wired into
the circuit.
OUTLINE 3-1-16
-3-
Three- and Four-Way Switches
If you wish to control a light from two
places, it is necessary to have two threeway switches. When three-way and fourway switches are combined, you may control your light from three or more points.
Use of these is very common in controlling
lights from opposite ends of the room, or
from both the top and bottom of the stairs.
with a delaying device built into it, and it
doesn't turn out the lights until a few seconds
after you have operated it!
e
;j
cl6:N I
'--
OFF
e
Weatherproof switch
Low Voltage Systems
This is a remote-control switching system that may be used in place of the threeway and four-way switches. A small transformer reduces the 115 volts to 24 volts.
This lower voltage is all that is carried on
the switching wires, so that they can be very
small, and need not be physically protected
as much as 115-volt wiring. This means a
great saving where switching wires must
run between buildings.
Door switch
Door Switches
When it comes to automatic controls for
lights, door switches are the most common.
They are found on refrigerators, ovens, and
closets, as well as on automobile doors.
They are spring-loaded, so that the spring
closes the circuit when the door is opened
and pressure is released from the button
which touches part of the door. They may
be installed in existing closets by an electrician.
Time Switches
Relay
These will turn on lights at a certain time,
and off at another predetermined time.
A time switch consists of an electric
clock, with contactors that can be adjusted
to do your switching for you.
24-volt transformer
Push-button
As many small push-button switches may
be installed in this 24-volt circuit as are
needed, and the lights can be controlled from
as many locations. A push on any of the
buttons actuates a relay or electro-magnetic
switch which in turn controls the light.
Special Switches
There are many special situations where
switches must be installed, and there is
equipment to meet most of these needs.
For outdoor use, you should use only
switches in weatherproof housings. For use
where unauthorized per sons might operate
them, there are switches that may be operated only with a key. There is even a switch
Time switches are widely used in poultry
house lighting, on signs, and to control decorative lighting.
Time switch
Photoelectric control
Photoelectric Controls
Because we usually want to turn on the
lights only when it's dark, we can rely on a
light-sensitive device to do this for us.
The photocell is an electronic device that
actuates a switch, and the two parts are sold
together as a control unit.
OUTLINE 3-1-16
-4 Many times it is not desirable to operate
lights all night, or until daybreak the next
morning. In these cases, a time switch is
used with a photoelect ric control. The time
switch opens the circuit late at night, then
closes it again after daybreak, so that the
photocell can resume control.
What Did You Learn?
(Underline the right answers)
7. Low voltage systems can have (only
five, ten or more) switching locations.
8. The better way to control stairway
lights is (three - way switches, a network of
strings).
9. Door switches usually (open, close)
the cir cuit when the door is opened.
1. Early man had (safety, inconvenience)
in the control of his lights.
10. If you have a photoelectric control,
you (must let the lights burn until daybreak,
can use a time switch with it to turn them
off at midnight).
2. The main reason for wanting to control light is (economy, appearance).
Demonstrations You Can Give
3. (Safety, Convenience) should be our
first consideration in controlling lights.
4. It is possible to control a portable
lamp (only at the socket, from a wall switch
and at the socket).
Get as many different light controls as
you can. Try to arrange it so that you can
operate a light (it can be the same one) with
each of them.
Show how lights can be controlled with
each of them. Describe how each one works,
and tell its advantages.
5. To indicate whether a light is on in
your attic, you should install a (pilot light,
window in the ceiling).
For More Information
6. On a yard pole, you should (use a
weatherproof switch, locate indoor-type
switch on the side away from the prevailing
wind).
Ask your power supplier representative,
Extension agent, electric supply store, or
electrician for literature on various kinds
of light controls.
LIGHT
~r?-/·p;~
PCY.J£~
~~
TYPE OF CONTROL
~~~
~
r·
.
/
E.M. 2351
Page 8
LESSON NO. ·5 LIVE WITH LIGHT - OUTDOORS
A.
Outdoor Lights
Outdoor lights can safely provide convenience and enjoyment. The convenience,
enjoyment and comfort they safely provide depends upon the type of l~ghts
used, where they are placed, how well they are installed and how they are
controlled. In this lesson you learn about outdoor lighting - the types of
lighting fixtures to use and how they should be installed.
B.
Review:
1. Explain the difference between spot and flood lighting and where each is
used outdoors.
C.
D.
2.
Why are waterproof fixtures necessary for outdoor electrical use?
3.
Explain the difference between fluorescent, mercury and incandescent
lamps.
Activity:
Plan an Outdoor Light Installation
a. Pick some outdoor area around the house that you would like
to see well lighted.
b.
Draw a plan showing how the light will be installed and wired.
c.
Make a list showing all the necessary materials and their cost.
d.
When you have completed your outdoor lighting plan, ask a
local electrical contractor or an electrician from your local
electrical utility to review the plan with you. He may be
able to suggest some changes that will improve your plan.
Demonstration:
See suggestions for demonstrations on page
4.
4-H
I
EL.ECTRI~
GUIDE SHEET
OUTLINE 4-S-9
LIVE WITH LIGHT-OUTDOORS
!50 -Watt
ith light, you can make the outdoors
around your home a place that is safe
and convenient, a place in wh~ch you can have
more fun, a place in which you can get more
work done, and a place that you'll be proud
to show to your friends.
W
PAR 38
Flood or
Spot ltghts
tn Sw tvel ·
Type Outdoor
So c ket
1" x 6 " x 20•
'
What to Do
lf4 " X
}6"
Ptpe
/
Pick an outside area around your home
that you would like to see well lighted. De ...
cide the purposes for which you would like
to light it- for safety, play, work, or beauty.
1.
2. Make a plan for lighting it. List the
wiring materials, fixtures, lamp bulbs, and
the cost.
3. Make one or more spike-pole outdoor
lights similar to the one pictured here, or
----'!"
one or more garden lighting shields.
Light for Safety, First
'
Thumb
lock Screw
in Dnlled
and Tapped
HoJe
For work
Does your home have porch or entrance
lights? It probably does, and it may well
have a post lantern or some other kind of
yard light.
The main reason for such lights is safety.
When they are turned on, they help people to
see stairways and other obstacles over which
they might fall.
For play
11,4" x 7 ' Pipe
-+----+-
Porch, entrance, and yard Ughts also discourage vandalism, intruders, and thieves.
They are regarded as essential.
Light for Convenience
for cooking
cmd eating
Outdoor lights also make it convenient
for us to walk around outdoors without having
to bother with a flashlight. This is .e specially
true on the farm, where people must travel
between the house and other buildings, often
with their hands full.
\11" X 18"
Just how convenient such lights are depends on how many there are, how well they
are placed, and the way in which they are
controlled.
-Pipe
OUTLINE 4-S-9
- 2-
Generally speaking, lights for safety and
convenience should be placed as high as possible without shadowing heavily traveled
areas. (A light high above the back porch
might make the roof cast a shadow on the
steps.)
Such lights can be located on poles and
will cover more area than if mounted on a
building. Use 150-watt PAR 38 floodlamps,
located 10 to 20 feet above the area to be
lighted, or regular pole lighting fixtures.
For walks near the house, you can use
dome type units about 16 feet apart with 25
to 50-watt bulbs.
They can be controlled with three-way
or four-way switches, with low-voltage controls, with photoelectric controls, with time
switches, or with a combination of the last
two methods.
Are the outdoor areas around your home
lighted for safety and convenience ?
Light for Play
Have you ever had some friends at your
place in the evening, and wished that you
had enough daylight to let you play croquet,
horseshoes, badminton, or some other outdoor game?
You should light the areas for such games
in a generally uniform manner.
Be sure
to keep direct light out of the players' eyes.
A light source well above eye level on a
building or pole is usually best.
Light for Cooking and Eating
Most everyone agrees that food tastes
better outdoors. Lighting of the cooking and
eating area will help the cook and make backyard picnics easier and more fun.
To light the outdoor fireplace or barbecue, use 150-watt PAR 38 floodlamps, located 10 to 20 feet above the ground, and
aimed in several directions to soften shadows.
The table can be lighted in the same way,
or you can use two 10-inch weatherproof
plastic "bubble" fixtures with 60 to 75-watt
bulbs, suspended three to five feet above and
slightly to one side of the table. When you
put lights near the table or fireplace, use
the yellow bulbs that do not attract insects.
Light for Work
Do you ever run out of daylight when you
have some important work to do on your outdoor 4-H project?
You can do many jobs after sundown if
light is available. In fact, the cool of the
evening is often the best time to mow the
lawn or work in the garden. Portable flood
lights will do for this kind of work.
Jobs such as painting and other do-ityourself projects require uniform light of
fairly high intensity, and freedom from
shadows.
Light for Beauty
Are you especially proud of the 4-H flower
garden you have planted, or of the way you
have beautified the grounds around your
home?
If you will light them at night, you can
enjoy them more yourself and can share
more of their beauty with other people.
Sidelighting or oocklighting works best,
because front lighting makes things look flat
and uninteresting. There are several kinds
of commercial garden lighting fixtures available. The dome or mushroom type is most
common. Use 25 to 40 watt bulbs in them,
12 to 14 inchesabove the flowers. Or, conceal a weatherproof lampholder in a sprinkling can or other kind of shield.
Remove side handle
--:~.,
Cut out side '-...........'
--------
away from spout
-
-
~
- ___,....
Old
sprinkling can
Weatherproof
adjustable lamp holder with " PAR" or " R" lamp
-3-
Be careful about shadows. When they are
carefully controlled, they add to the beauty.
Out of control, they can produce some weird
effects.
OUTLINE 4-S-9
Consider your neighbors.
Carelessly
located lights can be very annoying. Place
or shield your lights so they will not disturb
other people by shining on their property.
Use These Kinds of Bulbs
Equipment for outdoor lighting should be
durable, moisture proof, rustproof, and
preferably grounded to prevent electrical
shock. Indoor fixtures and extension cords
are unsatisfactory and can be dangerous.
Use weatherproof porcelain sockets, sealed
with a gasket.
First, let's take a look at the light bulbs
available for outdoor lighting.
1. Projector (PAR) Lamps - are available for spot or flood lighting. Try both
since they throw quite different beams. They
are made of hard glass and will not break
when water strikes them. You may need a
snap-on shield or reflector to eliminate
glare. Colored covers are also available as
shielding devices and fit directly on the rim
of the lamps.
2. Reflector (R) Lamps - also come as
spot and flood lights in various colors. However, they must be protected from the weather. A spatter of rain or snow can break
them when they are hot.
Various types of holders. Some you can make;
others you can buy.
You can light trees or shrubs to accent
unusual foliage, bark, or shapes. Select
open, artistic forms instead of solid masses
of foliage.
An evenly lighted area seldom creates an
interesting picture. This usually means
using several small lights rather than one
large one.
Restrain the amount of light used. Do
not try to produce a daytime appearance.
Too little light is better than too much, and
a soft glow is better than a glare. Conceal
wires and hide the light bulbs as much as
possible, using plants or shields.
3. Inside Frosted Lamps - may be used
outdoors unprotected in wattages of 15 and
25 watts. Higher wattages should have
shielding from moisture.
4. Yellow lamps are sometimes called
"bug lights". Since insects see only the blue
part of the light spectrum, yellow bulbs eliminate most of the light that attracts them.
Remember, however, that yellow light deadens the color of foliage.
5. Mercury Lamps - produce a blue. white light that flatters most foliage. They
are available in PAR bulbs and in tubes.
They need special sockets and auxiliary ballast to operate properly.
6. Sign Lamps - are weatherproof and
useful for garden, and decorative lighting.
They come in white and eight other colors.
OUTLINE 4-S-9
- 4-
7. Christmas Lamps - come in varied
colors and are very effective for a party
atmosphere or ·holiday decorations.
8. Fluorescent Lamps - Use them where
you want light on vertical surfaces such as
fenc es or hedges.
These Fixtures Work Best
1. Adjustable Holders - are used for
P.;. . R projector lamps and others. In singles
or clusters, they are available with spikes
for ground placement, plates that attach to
walls, and clamp.s for use on trees and poles.
wiring has a number of advantages. It makes
installation of lighting equipment easy, avoids
the hazard of cords stretched across lawns
and walks, permits the use of appliances
and small power tools outdoors, and because
it must be grounded, is much safer.
Portable Cords - Most outdoor lighting
equipment has up to 12 feet of weatherproof
cord. Weatherproof portable cord sets,
which handle several lighting units, are
available. Some lighting fixtures have builtin outlets to connect additional units. (WARNING --these outlets may not be intended to
carry appliances or power tools. ) Plugs,
sockets, and splices on cords should be
molded in rubber to keep the cords weatherproof.
~
2. Dome or Mushroom Units -are used
for general lighting on a terrace or where
you want the light directed down. The stem
will vary from two to five feet. The bulb
wattage is optional.
3. Flush and Surface Mounted Units direct the light horizontally and down. These
are located along paths or walks near buildings. The lamp size usually varies from 6
to 25 watts depending on the unit.
~· '.
-~
·~··
Flush
Surface
11
Bubble 11
4. Diffusing Plastic Shade - or "bubble"
unit is attached to a suspended socket. It is
used for general terrace lighting with a roof
or overhang. They are available in 10" diameters on up. Wattages vary from 40 to
150 watts in the larger sizes. With smaller
bulbs inside, they are very decorative.
. ~ /
::
'
Outdoor duplex outlet
Weatherproof outlet cover
Galvanized conduit
Bushing
Cable
,;
Protective covering
· 311 fine soil or sand
Permanent Wiring - offers maximum
safety and convenience. Plastic wire types
USE or UF can be buried without enclosing
them in ~onduit. If the soil is rocky, place
a layer of sand or fine soil in the trench as
a bed for the cable. A slight "S" should be
made in the cable where it enters the house
to allow for expansion or contraction. Separate circuits for outdoor lighting equipment
should be provided for in the main house ·
panel. Be sure that one or more convenient
controls are installed.
Demonstrations You Can Give
5. Telescopic Poles - use holders for
PAR lamps or enclosed floodlamp holders.
They fit into pipe sleeves driven into the
ground or have a floor base.
Show various bulbs and fixtures suitable
for lighting outdoor areas, and te 11 what
each is best adapted for. Show some "before" and "after" pictures of an area that
has been properly lighted.
Wiring Should Be Right
For More Information
For full enjoyment of outdoor lighting,
adequate wiring is essential. It may be
temporary or permanent, but permanent
Ask the home or farm representative of
your power supplier, or your county Extension or home demonstration agent.
E.M. 2351
Page 9
LESSON NO. 6
WHAT MAKES MOTORS RUN
A.
The Electric Motor
We depend on electric motors in many ways. Motors operate refrigerators,
washing machines, clocks, fans, etc. Yet very few people understand how a
motor operates. In this lesson you will learn about magnetism and electromagnets. Then you will learn the function of different parts of an electric
motor. Before you start this lesson, review Lesson No. 1 of Unit I, to remind
you of the difference between A.C. and D.C. electricity.
B.
Review:
It is quite important that you study this lesson well. If you do not understand the lesson, ask your leader, your parents or someone familiar with
motors to explain the lesson further. After answering the following questions you will know how well you understand the operation of an electric motor.
C.
1.
What is the purpose of the two electromagnets in a motor?
2.
What is the purpose of the commutator?
3.
What is the armature?
4.
How can you reverse the direction of rotation of the motor?
5.
Explain why the direction of rotation changed.
Activity: Make an Electric Motor
After you understand how an electric motor is built and why it operates, you
should make a simple motor. To make a motor, follow the steps on pages 3
and 4.
Materials needed -- see page 3
Necessary tools --- see page 3
Assembling the motor ---- see pages 3 and 4
Note: the pictures under "Step No. 2- Commutator,n on page 3, show
the scraped ends of the armature wire laced back and forth on each
side of the commutator only four times. Each wire should be laced
back and forth until it reaches one-half way around the shaft, rather
than only part way around the shaft. About twelve inches of spare wire
on each end should be allowed for this purpose.
Additional Activity: Visit an Electrical Repair Shop.
If there is an electrical repair shop in your community, ask your leader to
help you organize a visit to it. The electricians are usually pleased when
someone shows interest in their work. They can show you many different kinds
of motors they work on.
D.
Demonstration:
See suggested demonstration on page 4.
I
4-H ELECTRIC GUIDE SHEET
•
0
WHAT MAKES MOTORS RUN _
U-TLIN-E5-Ba.i-
W
hat makes an electric motor run? Can
you make an electric motor that will
run? Certainly you can, and by doing so
you '11 learn why it runs. It won't be mysterious any more and you'll be ahead of all
the millions of people who use motors every
day and never know why or how the motor
converts electrical energy into useful
power.
Motors Are Magnets
You know how one end of a compass
needle always points to North. No matter
how you turn the compass, the same end of
the needle always swings to the North. The
earth itself and that small compass are
both magnets (Figure 1). Each has a North
pole and a South pole. Around the poles of
each there are magnetic fields, invisible
lines of force that attract and repel.
repel each other and almost flip around until there's a N pole lying next to a S pole
(Figure 2).
NORTH POLE
MAGNETIC LINES
OF FORCE
AROUND EARTH
SOUTH POLE
Figure 1. The same end of the compass needle always points to the earth's magnetic North Pole.
The N poles reP.el each other and so do
the S poles. The Nand S poles attract each
other. In other words, opposite poles attract; poles that are alike repel each other.
Lay 2 bar magnets on a table side-byside. If both N poles are at one end, they'll
Figure 2. Small bar magnets laid side by side move
so that the North pole of one is near the South pole
of the other.
Now suppose we place one of the bar
magnets on the table. The other, we'll fix
on a pivot so it can spin around. This one
we'll move so its N pole almost touches the
fixed magnet's N pole. As soon as werelease it, the movable magnet will spin around
so its S pole will be near theN pole of the
-2MOVABLE
OUTLINE 5-B-4
Switching Poles Automatically
BAR MAGNET
FIXED
BAR MAGNET
Figure 3. A movable bar magnet pivots so its South
pole is near the North pole of a stationary magnet.
stationary magnet.
motor- almost.
That's an electric
It's not quite a motor because the rotating magnet will just move as far as it
has to in order to get the opposite poles
together. You might be able to cause the
movable bar magnet to make turn after
turn. You could do this by turning the fixed
magnet quickly end for end. This wouldn't
be very practical as a motor.
We Can Improve It
If we could change the pole on one end of
the rotating magnet just as soon as it
reaches the attracting pole, it could make
a complete circle. In doing that, the pole
at the near end of the rotating magnet would
be repelled by the stationary magnet and
pushed away. As soon as the opposite end
of the rotating magnet would come into the
magnetic field, it would be drawn to the
stationary magnet. In order to keep the
"motor" running, we would have to constantly change the poles at each end on
every half revolution.
We Need An Electromagnet
We can't reverse the poles on simple
bar magnets, but we can on electromagnets.
We can make one by wrapping a wire several
times around an iron core to form a coil.
This magnet will also have a N and a S pole
when connected to electrical current. The
big difference is that the poles can be
changed instantly by reversing the current
in the wire.
The rotating electromagnet will have to
be connected to the 2 wires through which
we pass the current. Since it's rotating on
a center shaft, we can't have a solid connection.
Instead we have to extend the
wires from the coil out along the shaft and
let the electric contact be made with
brushes which touch the wires along the
shaft.
ROTATING
SHAFT
... ...
,
IRON CORE
ENDS OF WIRE WINDINGS
(COMMUT A TORJ
,,
, ,,,
,JJ.'
,' ,
,
...,._, ,
,,'
Figure 4. A rotating electromagnet changes poles as
contacts are made first one way, then the other.
This is a simple way to reverse the current in the coil of the electromagnet.
Increasing Efficiency
Instead of using only one pole of a
stationary magnet, we can use both. This
is done by shaping the stationary magnet
around the path of the rotating electromagnet. This way we have the benefit of
the attracting and repelling forces from
both poles. The effect is doubled.
We can also wrap wires around this
circular iron and make an electromagnet
of it. But when we wire this magnet we
use no brushes because we want the current to flow in one direction only.
The stationary electromagnet is called
the field. The rotating electromagnet is
the armature.
OUTLINE 5-8·4
-3-
WHAT TO DO: Make A Motor
Step No. 2 - Commutator
Tools Needed:
Pocket knife, hammer, vise (or 2 pairs
of pliers).
Materials Needed:
1 roll of No. 24 enameled wire
1 roll of electrician's tape
3 - 4" (20-penny) nails
4 - 2-1/2" (8-penny) nails
4 - 3'' brads _(1 0 penny)
Wood board for motor base
2 staples or 4 small brads
2 tacks
2 - 3 volt dry cell batteries (or a 6
volt transformer).
Scrape all insulation off the ends of the wire.
Bend the bare ends back and forth as
shown. Lay them flat over the taped shaft
- one on each side of the shaft.
Step No. 1 - Armature
Wrap about 1-1/2'' of a
4" nail with two layers of
tape. This will be the
shaft.
The iron core will be
made of two pairs of
2-1/2" nails. Wrap tape
around each pair with
heads and points alternated.
Hold the commutator down with narrow
strips of tape. Wrap tightly near the core
and at the opposite end.
Step No. 3 - Field
Make the core by bending
two 4" nails in the middle
at right angles. Space the
heads about 3'' apart to
form a horseshoe. Wrap
together with two layers
of tape.
FIELD POLES
Center both pairs on each
side of the shaft. Place
them about 1'' from the
head of the shaft nail.
Wrap them together with
two layers of tape from
tip to tip.
Start at the shaft and wind
No. 24 enameled wire to
one end and back. Then
do the same on the other
end. Always wind in the
same direction. Leave 6"
of spare wire at start and
finish.
COMPLETED
FIELD
Wind about 400 turns of wire around the
center. Leave 4" of spare wire at start
and finish. Attach to wood base with staples
at each end of the wire. Small brads, bent
over, will do just as well.
OUTLINE 5·8-4
-4-
Step No. 4 - Armature Supports
and Brushes
ARMATURE
SUPPORTS
BRUSHES
Adjust the position of commutator and
tension of brushes against it for best operation.
Take the armature off the motor and
connect the commutator wires to a dry
cell battery. Test the polarity of each end
of the armature with a compass. Switch
the connections on the commutator and
test again. See how the compass needle
changes direction?
··--..:-....--... ___
...
Scrape the insulation from the ends of two
6'' pieces of wire. Tack them to the base
and bend them as shown to make brushes.
Drive two pairs of 3" brads into the base
about 3-1/ 4" apart and in a line midway
between the field poles. Wrap wire around
the supports to form armature bearings.
Scrape insulation off ends of wire from the
field. Connect one end to a brush wire.
ARMATURE~
Assemble As Shown
ARMATURE
SUPPORTS
With the armature still off, connect the
field coil directly to the dry cell. Test the
polarity of each end of the field with the
compass. How can you reverse the polarity? Try it. It's easy.
Reassemble the motor again and start
it.
Push the field poles slightly out of
alignment with the turning armature. What
happens to the motor's speed? Can you
tell why?
This time, push the field poles completely out of the way. Test the polarity of
the armature as you slowly turn it by hand.
Do you see what happens and why it does?
Try to reverse the direction of rotation
of your motor by reversing the connections
at the battery. What happens 1 Can you explain why?
Demonstrations You Can Give
Make a display board showing the parts
of the toy motor and explain how each part
works compared with the parts of a commercial motor.
For Further Information
TO BATTERIES
There are several other types of toy
motors you can build. Your club leader or
power supplier canhelpyoufindinformation
about them.
E.M. 2351
Page 10
LESSON NO. 7
A.
TAKING CARE OF ELECTRIC MOTORS
The Care of MOtors
With proper care an electric motor will work for several years without costly
repairs. In this lesson you will learn how to care for motors so they can do
their job well.
SAFETY NOTE: Do not work on a motor while it is in operation. If you do, you
may receive an electrical shock. Also, you may d.amage the motor.
B.
Review: Answer the following questions. Ask your leader or parent to check
the answers so you will be sure you properly understand the lesson.
l.
Answer the questions on page 2.
2.
Where will you find AC motors?
3.
Where will you find DC motors?
4.
What is the difference in construction between a motor that operates
continuously and one that operates only occasionally?
5.
Why do some motors have sealed bearings while others don't?
6.
Define:
horsepower
C.
Activity: Servicing Electric Motors.
l. Ask your parents to let you service some electric motors around your home
or farm. Carefully follow the steps for servicing motors outlined on pages
1 and 2. Make a chart showing the motors you serviced and what you did
for each motor. Use a chart similar to the chart shown on page 3.
D.
Demonstration - See list of suggested demonstrations on page 2.
4-H ELECTRIC GUIDE SHEET
~
OUTLINE 3·8-S
~
TAKING CARE OF ELECTRIC MOTORS
hrough the magic of electric motors,
T
much of our work is done faster and
better at lower cost than we could do
it
without the help of the electric motor.
People who use motors and treat them properly have much more time for other work
and for leisure time activities. A 1/4horsepower motor running quietly and steadily hour after hour will do the work of one
man, and operate all day for about 5 cents
without tiring. On many jobs it will work
without ''supervision'', turning on and off
automatically, as required. It does this on
water pumps, in heating and cooling units,
and on fans and similar appliances.
All that a motor needs to do its work is
electricity and a little care, Let's see what
you can do to give proper care to motors in
your home and on your farm.
ing off the motors, and a tire pump or
vacuum cleaner for blowing out the dust or
dirt.
WHAT TO DO
You'll Need
A light oil (SAE 10) for motors of less
than one horsepower and a slightly he a vier
oil (SAE 20) for larger motors. See if you
need grease for cups which may be on large
motors. If so, be sure you use ball-bearing
grease and not ordinary cup grease. Cotton
waste or clean rags will be needed for wip-
1. First, make a list of all the electric
motors that work for your home. You may
wish to make a separate list for your farm
buildings. You'll probably be surprised at
how many there are. Don't forget the sewing machine, the refrigerator, the freezer,
the vacuum cleaner and other small but important motors. Don't touch any motorthat
is running. Disconnect them before you
touch them.
STYLE
THERMAL
PROTECTION
OIL YEARLY AFTER 2
YEARS FOR NORMAL
OPERATION, OIL TWICE
A YEAR FOR FREQUENT
OPER-ATION,
Some motors have instructions for oiling on the nameplate.
2. Make a motor service chart with
columns headed:
Use, Location, Horsepower, Volts, Amperes, Service Required,
Date Serviced and What was Done. (See
sample) Then list all the motors that require any servicing. Some will have the instructions on the motor or appliance; the
instruction booklet that came with the
motor or appliance will also tell what servicing is required.
Step 1. Plan the job.
Start with the
motors in the home. Then you can care for
the motors on the farm.
-2Step 2e Be sure that any motor on which
you are going to work is disconnected"
Then wipe the outside case clean with a
cloth. If the motor has openings in the end,
use a vacuum cleaner to suck out dust, dirt
or chaff. A tire pump may also be used to
blow out this dirt. If you use compressed
air, be sure the pressure is not high as it
may damage wiring inside the motor. Dustproof motors should be used in dusty or
dirty places.
OUTLINE 3-B·S
What Did You Learn?
How many motors are there in your home?
_ _ _ On the farm? _ _ __
How many motors need regular oiling or
grease? _ _ __
How many are
power? _ _ __
less
than one-horse-
Step 3.
SAE Oil
is used to oil motors up to
1/2 horsepower. How much oil? _ _ __
SAE Oil ___ is used for larger motors"
Demonstrations You Can Give
If there are oiJ holes, oil according to the manufacturer's instructions.
If there are no instructions, remember
a little oil goes a long way as far as motors
are concerned. Motors of less than one
horsepower require only 3 or 4 drops (not
squirts) of oil every 3 or 4 months if the
motor is used frequently. Too much oil
can damage the motor. It spoils the insulation.
If there are no oil holes or grease cups
on the motor, it is probably lubricated by
means of grease sealed in the bearings at
the factory, or it may use greaseless bearings, and does not need to be oiled or
greased periodically.
Indicate on your
chart all motors which need periodic care
and see that it is given according to
schedule.
Wipe away any excess oil or grease. Be
sure oil holes are capped or covered.
Step 4. Reconnect motor and run for a
moment.
Step 5. Record on the chart the date you
serviced the motor and what was done.
1. Show how to clean a small motor.
2. Explain proper lubrication of motor~.
3. Using the chart prepared in this work
sheet, give a talk about the motors that
work for you - the job each one does,
which ones need oil or grease, which
need no attention, and why, etc.
4. Use a homemade toy motor to explain
"what makes motors run."
5. Show proper way to replace worn cord
on a small motor.
For Further Information
Ask your county Extension agent or 4-H
leader for more literature on motors. They
can help you obtain a film or a speaker
such as a power supplier, a local electric
dealer, or electrical contractor to discuss
·motors.
Also visit your public library and see a
science teacher for more information on
motors.
-3-
OUTLINE 3·8·5
ELECTRIC MOTORS SERVICE CHART
Sample
Use a table like the following to list the motors around your farm and home.
Motor Use
Food Mixer
Location: H.P. : Volts :Amps.: Service Needed
Kitchen
Tool Grinder: Farm
: shop
Pump
: Pump
: house
1/6
120
1/4
120
4.4
Clean & Oil;
cord needs
repair
Date Serviced and
wba t was done
9/1-Cleaned w/cloth.
Oiled w/#10 oil;
repaired cord.
: 5.8 : Clean, oiling; : 1·0 /6-Cleaned w/vacuum..;
: HB.ve switch
: Oiled, #10 oil. 10/20: repaired
: Had switch repaired
:
: 1/3 : 120
.
.
: 7.2 : Oiling,
: cleaning
: 9/26-C1eaned w/tire
: pump; oiled w/10 oil
~--------·-------------------------------~----------------~-----~--------~---~----
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