CHAPTER I
INTRODUCING YOU TO ELECTRICITY
What’s a watt? This is not a comic opera refrain, but a question asked so many times that it is typical of the lack of knowledge people have to-day of the force which they are using constantly in their own homes and others.
We have lived to see women go to automobile schools and learn the working of the car which is theirs to drive. But as yet there seems to be no course even in the domestic science school which gives the household engineer an inkling of what is to be her mechanical field in the realm of electricity or ordinary mechanical construction. We hope this will come.
For have you ever stopped to think that the housekeeper to-day presides over an extensive electric installation? Even if she has but a telephone and an electric bell in the house, there is much that happens that ought to be familiar to her.
But people to-day have much more than these few things; they have at least three or four of the following: ironing machine, washing machine, vacuum cleaner, telephone, warming pad, electric lights, toaster, electric piano, sewing machine, curling iron, electric range, electric iron, etc., yet the underlying principles and vocabulary are still as Sanskrit to the majority of users.
This article is but to make simple and comfortable electric terminologies and we will use this for an excuse to get at a few electrical misusages. It is to make electricity familiar rather than a stranger to the user. Nobody knows what electricity is, so fortunately, we don’t have to stop and define it. All that we know is that it acts in certain definite ways.
We get electricity from the battery and from the generator (dynamo). The battery consists of celled containers which come under the heads of dry and wet batteries in so far as they contain liquid or solid (wet) ingredients, through which the electricity is generated and passed out by means of wires. In short the battery produces electricity by means of chemicals. The primary battery produces electricity and the storage battery stores it in the form of chemical energy. It is useless for purveying very much electrical power as there never can be enough pressure (voltage) to send along the electricity to do big jobs, unless hundreds of cells connected in a certain way were used, which would be a foolish waste of material and time, etc.
In order to obviate such manufacturing the generator or dynamo is used and electricity is made in this way by induction. In other words, we make it by letting a coil of wire (or several coils) be revolved by steam or water power (usually) as it cuts through the area of magnetism (field) of a giant magnet something like those we used when we were children. This coil catches the electricity and it is led off by wires wherever we want it to perform. The coil on the spindle is called the armature, where the wire is attached to lead off the electricity from the armature are contact-pieces, and the plates which make the contact with the contact pieces and to which are attached the wires of the out-going electric circuit are called the brushes. There is much more to say, but not in this article. If you are interested we refer you to Charles R. Gibson’s “Romance of Electricity” for simple electrical explanations.
The motor with a few mechanical changes is the reverse of the dynamo; it works by electricity and changes it into mechanical power to work our washing machines, etc. There are on the market A. C., D. C., and Universal motors. These you will understand after the next section which takes up A. C. and D. C. electricity.
“Madam, do you use A. C. or D. C.?” asks the man selling you a washing machine. Most decent folks are quite at sea at this seemingly geographic question, and yet after all it is the most complicated simple thing in the world. D. C. doesn’t mean District of Columbia; it simply means Direct Current. And A. C. means Alternating Current. And on these two kinds hang all the wires of electric profits.
Direct Current or D. C. is a current that runs in one direction over the wire like water through a pipe. It is simple to visualize, even if electricity does flow 163,000 miles per second. But alternating current (A. C.) is electricity which alternates and goes back and forth, generally. Even though it goes back and forth in waves of tremendous rapidity, you can see that there must be a time in this period when the electricity is for an infinitesimal space of time at low power, and another infinitesimal space of time at high. In order to keep the supply even and steady, two and sometimes three coils of wire are used in the generator to catch the electricity so that there is scant opportunity for the electric supply to be anything but even, for when one coil is up the other is down and thus they even up the strength of the current.
So when your salesman asks you when you buy a motor, “If you have A. C. or D. C. electricity” and you say A. C. he may go on and say, “How many phase?” Then you should find out the answer from your lighting company. He then may ask you how many cycles, which when translated means the electric period it takes for the alternating current to flow back and forth.
Now dynamos for D. C. and A. C. electricity vary slightly, but that need not trouble _us_.
The reason for two kinds of electricity at all is that each, though obeying the larger laws, has its own peculiar habits and good points.
For example, alternating current can be carried long distances at high pressure (high voltage) and side-tracked by a transformer to a little home and the pressure very simply reduced. In other cases the pressure can be very simply increased. Therefore in country districts one is very prone to see A. C. in vogue.
The same amount of current, whether D. C. or A. C., is used for lighting, etc.
A. C. is not used for electro-plating, etc., or for storage batteries. This is a good point to remember if you have storage batteries to supply for bells, etc., and your current is A. C. You will have to have your batteries charged from a plant which makes D. C. or install a small “converter.” If you attempt to use the A. C. you will burn out your plates.
But how is electricity measured? How, in other words, do we know how much we use and how can we test our bills? The following paradigm will give the electric measures translated into more familiar terms of water measurement:
Volt Pressure Ampere Rate of flow of current per second Watt Fraction of horsepower (H.P.) Kilowatt (1000 watts) 1¹⁄₃ H.P. Resistance Friction (as water resists the sides of a pipe.) Ohms (the unit of Friction (as water resists the sides of a measuring resistance). pipe).
The volt takes its name from Volta, an Italian scientist; the ampere from a Frenchman, the ohm from a German, the watt from an Englishman. We hear most about volts and watts. Voltage is found by multiplying the ohms by the amperes. The volt is the pressure that makes electricity flow through the wire, and the friction of resistance to its flow is measured by the ohm.
The amount of work a given number of amperes will do at a certain voltage (pressure) is known as watts.
So if by chance you ever need formulæ here is a little one for your card catalogue:
Ohms×amperes=volts. Volts÷ohm=ampere. Volts×ampere=watts. 1 Kilowatt=1000 watts. 1000 watts=1¹⁄₃ H. P.
The next thing which is necessary for the householder to know is how to compute costs of electrical usage.
The amount of electric power used, for example, by the electric light is measured in watts. Look on any incandescent bulb and you will see thereon the number of watts--usually around 50 or 60.
In order to know how many watts a light consumes, divide the number of watts it consumes by 1000 to reduce it to a something of a kilowatt. Then multiply this result by the number of hours the lamp has been lit by the kilowatt to get the kilowatt hour of electricity. The kilowatt hour, of course, multiplied by the rate per kilowatt hour in your locality will give you the cost. The rate is always figured on the kilowatt hour.
Watt÷1000=kilowatts. Kilowatt×hours=kilowatt hours. Kilowatt hours×rate=cost.
Probably it would be a good thing to know how to read the meter, which generally consists of four little dials which are read from right to left. The first dial measures the tens, the second the hundreds, the third the thousands, the fourth the ten thousands. Therefore
if the hand in the left has passed 9, that would stand for 9000 In 2nd dial nearest to 1 that would stand for 100 In 3rd dial nearest to 2, that would stand for 20 In 4th dial nearest to 1, that would stand for 1 ---- 9121
The total is 9121 kilowatt hours and this multiplied by the rate (say ten cents) as it is in some places, would mean that the bill for this consumption would be $92.2. Now, knowing from your last month’s bill that the reading of the meter then was 82000--by subtracting you find that the actual current consumed was 921 K. W. hours, which multiplied by rate (say ten cents) gives you $92.10 as your bill.
To quote from an article in this series on electric ranges will give you an idea as to how to buy in accordance with voltage and how the cost is reckoned in watts:
“It is necessary when ordering a range to give the voltage of your electricity supply. The stoves are usually prepared for 110-220, 110 volts with two wire service from the street or 110-220 volts with three wire service. In some stoves the cut-out box is built on the range directly back of the switches. This, then, can be easily opened if anything happens. In the stock stove there is made an extra charge for voltage exceeding 220 or less than 110, because alterations have to be made.
According to the size of heating elements in the stove, etc., the wattage runs from 10,000 watts or 10 kilowatts, which is the same thing, to about 2500 watts, or 2¹⁄₂ kilowatts on a small three-heating-unit range. This gives its total capacity if everything goes at once. The number of watts used, multiplied by our local rate, say four cents, gives the cost per kilowatt hour, which in this case would be 40 cents per hour.
Have you ever wondered how electricity changes from current to heat? Have you ever wondered how we can cook, and iron, and warm a room by it?
It is due to electricity’s resistance, which is measured in ohms. It is resistance which is turned into heat. The process of overcoming resistance results in throwing off heat. It is quite familiar.
Did you ever rub a piece of wood in the palm of your hand for a little while and feel the heat given off? We call it friction, but it is really the giving off of heat due to expenditure of mechanical energy.
The same thing happens with the electricity. This electricity which travels at the speed of 163,000 miles a second, when it comes into frictional relation with its conductor pushes aside the molecules of the metal, and here the mechanical energy is magically transformed into heat.
SOME TECHNICAL TERMS
When we hear short-circuit mentioned, what does it mean to us? Well, it should mean that the path of the electricity (electric circuit) has been suddenly shortened, the electricity has escaped through the ground or over another conductor.
Insulation is the covering by which the escape of electricity through the wire is made impossible. Always see to it that the insulation is in perfect condition.
All wires must be insulated. In damp places rubber covered wire must be used.
Wires must always be protected with porcelain tubes passing through
## partition walls, girders, and where they pass over pipes, and other
wires, etc.
Incandescent lights are merely globes with a vacuum in which a filament of tungsten or some other highly resistant material meets the electric current and glows through its very resistant power.
The switch is merely a device to open and close the path of electricity.
The socket is the termination of two wires from the generator or battery, into which the bulb of the light is put and other connections made.
You will notice two wires on every electric connection. This is to make a complete electric circuit (path) to and from the points where it is used.
The outlet is the opening where the socket can be placed. The more outlets you have in your home before building the better off you will be forever and ever. A convenient outlet (sometimes called a baseboard or wall receptacle) is simply a place for conveniently connecting electric appliances to your electric current.
Fuses are things we hear much about. They are the stop-gaps really between danger and safety and though they make a splutter when they “blow out” it is right that they should. Briefly, the fuse is a bit of lead or other metal with a low melting point so placed that when the circuit gets overloaded for any reason the metal will melt and open the circuit, stopping the electricity and preventing danger.
When the fuse burns, we call that a blow-out, but this burning has saved us from dangerous currents.
Every house should be well supplied with fuses, and as soon as they are blown out, restored. Your superintendent or electrician will show you how to restore the oft blown-out fuse. So it is wise to keep a few new fuses in one’s home.
The fuse will blow out sometimes if you allow a bit of metal from a lamp shade to cavort too intimately with the excitable parts of your incandescent bulb; then the wire gets overloaded and the tin or lead conductor on the fuse melts and prevents the greater current doing any damage. It’s simple, isn’t it? The fuses come in convenient shape. Sometimes it is wise to use a rubber glove when putting them in. We have seen a sparking do a bit of burning.
Electricity is not dangerous when properly employed. It is dangerous when you use it wrongly. If you put your hand under a boiling hot stream of water you will get burnt. If you put your hand on a red hot stove you will get burnt; if you burn a fire in a wooden box you will have more fire than you bargained for; if you inhale gas you will die. Such is the case with electricity, which is a most controllable force if you are not ignorant as to how to use it. However, if you will put a hot curling iron on your table without turning off your current you will have a cozy little fire start up; so you would if you laid down a cigaret without putting it out. Most accidents occur simply because of such ridiculous carelessness. Mr. A. M. Grant of the Manhattan Electrical Supply Company said a wise thing in reference to this subject: “Before connecting any appliance to your lamp socket turn out the light in your bulb; then you know that your current is off. Never attach anything to anything electrical until the current is off and never go away and leave an appliance with the electricity turned on.”
More specifically, in using any electric appliance non-continuously, shut off the current immediately upon stopping. Do not only pull out the plug but turn off the electricity.
In using the flat-iron detach the plug at the iron as well as turn off the current from the socket.
Remove the iron from the goods and detach the plug when called away from the ironing board.
Never pull the plug out by the cord; always grip it at the spring.
Always replace at once frayed wires--as the ends often collide and make blow-outs.
Don’t leave your electric curling iron on the table cloth and do something else about the room without first turning off the current--or you’ll have a cute little fire.
Care must be taken in using too many cluster plugs, because the electric circuit (path) may be overloaded. That is, too much electricity drawn over the wire which is made for a certain load. Then your fuse will blow out. Extra appliances should be attached to different circuits. This a good electrician will regulate for you. Too much wattage (horsepower) over one circuit is like forcing any machinery to the breaking point. A percolator, toaster and a lamp are too heavy a load for the ordinary circuit. Connect at the same place only those appliances that are of low wattage.
Some firms have now made percolators and water heaters with fuse-nut or safety fuse devices which melt if overloaded or allowed to heat up without any liquid in them to be heated. You must not let a percolator “perc” without any water in it. People complain more about good percolators because their heating element burns out, either because they do this or because they have it connected up with too many other devices. Even if you do the right thing in these respects, don’t forget to disconnect the electricity by pulling out the plug.
Don’t get your electricity heating pad wet. In fact, don’t wet any electric appliance carelessly or you may have a short circuit.
Remember that electricity, magic as it is, can burn as well as any flame, so don’t let your curtains blow against a red hot electric radiator and then blame it on the electricity which after all is your servant if you make it so by right treatment.
Always ask your salesman to what the device purchased should be attached. Some things are designed for the ordinary lamp socket, and others need different connections.
Many electric appliances have the pilot light to tell you whether your electric current is on or off. Yet it is wise to be your own pilot and remember what you are doing.
Do not leave your electrical installation entirely to your architect. Watch what is happening. Remember you need as many outlets as you possibly can afford; the more you have the better lighting you can have, the better electric comforts you can have. If you have few outlets you are very prone to overload your circuit, and in the future as more electric devices come into being you will have to pass them up. Outlets consume no electricity but are simply entrances where electricity can be located as soon as the appliance is connected up with it and turned on.
Above all, have your electric installation put in by the most responsible and experienced people you can get to do it.
When you buy appliances always ask what voltage they require and find out what your own voltage is before you buy; also find out whether you have D. C. or A. C., and if A. C. find out what phase and cycle. These things will save you time and money and free you from any apprehension of calamity from the use of electricity.
There is much left unsaid in this chapter. It would take a book by itself to say everything.
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