Electric machine

“ If the machine has been properly built it is now ready for operation. It may be necessary to charge the machine the first time that it is used by touching several of the sectors with the charged cover of an electrophorus. Then if the handle is turned the accumulated electricity should discharge across the spark-gap at the top of the machine in the form of bright blue sparks.
Experiments with an Electric Machine Many interesting experiments can be performed with an electric machine. The number is almost unlimited. ”

“ A machine at Niagara receives mechanical power, and generates electricity. Call this the generator. Let there be Wires to another electric machine in New York, which will receive electricity, and give out mechanical work. Now this machine, which may be called the motor, produces a back electromotive force, and the mechanical power given out is proportional to the back electromotive force multiplied into the current. ”

“ The machine gets charged after a few turns of the handle, and the operator feels that, as the charging progresses, it gets harder to turn the handle. In large machines the manual work becomes so heavy that it is convenient to use an electric motor for working the machine. ”

“ In the electrical machines already described sparks occur whenever the carrier comes in contact with a conductor at a different potential from its own.
Now we have shewn that whenever this occurs there is a loss of energy, and therefore the whole work employed in turning the machine is not converted into electrification in an available form, but part is spent in producing the heat and noise of electric sparks. I have therefore thought it desirable to shew how an electrical machine may be constructed which is not subject to this loss of efficiency. ”

“ Now, when the Gramme machine was invented to supply currents of electricity under conditions much more favourable than the magneto-electric machines it superseded, and at a cost vastly less than that of any voltaic battery, it is highly improbable that the relation of the new current generator to the production of electro-motive power would long be overlooked. ”

“ To milk cows by electricity is simply to apply the vacuum-cleaner idea to the process, and, in general, doing things by electricity usually means doing them by some machine that is made to go by an electric motor. This then is the first key to the Electrical Show, and if you will remember to look first for the motor it may remove much of the mystery from some of the exhibits. In many cases it is not necessary to have a complete electric motor, but simply an electro-magnet to do the work. ”

“ Observations of Faraday and Henry—Magneto-Electric Machines of Pixii and of Saxton—Hjorth’s Dynamo of 1855—Wilde’s Machine of 1866—Siemens’ of 1867—Gramme’s of 1870—Tesla’s Polyphase Currents.
In the last thirty-five years of the Nineteenth Century there has grown up into the full stature of mechanical majority this stalwart son of electrical lineage. As the means for furnishing electrical power it stands to-day the great fountain head of electrical generation, and in its peculiar field ranks as of equal importance with the steam engine. ”

“ You light the burners on these machines as you light the gas, turn the electric switch and iron. It is quite simple and safe. Many of the machines have a pilot light to tell when the current (electric) is on or off. To heat by electricity all you do is to attach the cord to the ordinary wall socket.
A hand-power machine is driven by turning a handle. Thirty-five turns a minute is the right speed. It can be converted any time into a belt-driven machine and attached to the washing machine or anything else that goes by motor. ”

“ At the present time, a small electric machine which uses very little current can be obtained especially for this purpose, and these electric gluepots are much cleaner and safer in every way than the old-fashioned gas heaters. ”

“ The cushion should of course be well smeared with amalgam. From this, as well as from the glass-plate machine, the “positive” electricity can be drawn off and stored in a Leyden jar, and then discharged by the “discharging rod,” which is represented on the cut. It may have one or two handles, and one knob is placed outside the jar, the other near the ball surmounting it. The glass being a non-conductor saves the operator, and some long sparks and loud reports may be obtained.
Fig. 213.—Cylinder machine.
The Electric Machine is always assumed to give off positive electricity. ”

“ Of late years, however, a new method of producing electricity on a large scale has been discovered in the dynamo-electric machine, by means of which currents of great volume and intensity can be obtained from the power generated by a steam engine, water wheel, or other prime motor. ”

“ In the telephone for nearly two thousand miles the pulsations of the speaker's voice are not only audible, but retain their characteristic tones.
In the field of mechanics electricity is decidedly preferable to any other agent. Heat may be transformed into motive power by a suitable engine, but there its adaptability is at an end. An electric current drives not only a motor, but every machine and tool attached to the motor, [Pg 136] the whole executing tasks of a delicacy and complication new to industrial art. ”

“ The fifth machine was a big grindstone and the sixth was an emery wheel. The boys had a long discussion, running through several days, on the question whether these machines should be belted to the counter shaft, and thus get power directly from the water-wheel, or whether each machine should be operated by an electric motor attached to it. ”

“ It should be remembered, however, that high grade electric machinery cannot be built out of low grade materials and with poor workmen; therefore, when necessity compels the selection of a cheap machine, it should not be expected that its service will be as satisfactory as that of a first class machine. ”

“ An electric motor of small power—about eighteen kilogrammetres per second—controls the shaft on which the three rotary brushes are fixed, and the customer has only to unlock the machine, the same as all others of its kind, with his coin, and move the handle which opens the circuit and starts the motion. ”

“ The copper disc spinning between the poles of a magnet while an electric current was sent from the centre to the circumference, or vice versâ, formed the simplest electro-motor. All the later motors are simply modifications of this, designed to increase the efficiency or power of the machine. Similarly, the earliest machine for the production of an electric current at the expense of mechanical power only, but through the intervention of a permanent magnet, was the rotating disc of Faraday, described on page 262. ”

“ A dynamo or electric generator is a machine for transforming mechanical into electrical energy; an electric motor is a machine for transforming electrical energy into mechanical energy. If, therefore, we place an electric motor upon a vehicle and supply it continuously with current from a dynamo, the motor will rotate and can be used to propel the vehicle. That is the essential mechanism of electric traction. ”

“ Several other electrical machines have been constructed in which the principle of electric induction is employed. Of these the most remarkable is that of Holtz, in which the carrier is a glass plate varnished with gum-lac and the inductors are pieces of pasteboard. Sparks are prevented from passing between the parts of the apparatus by means of two glass plates, one on each side of the revolving carrier plate. This machine is found to be very effective, and not to be much affected by the state of the atmosphere. ”

“ Method of Starting a Motor.—Although motors and dynamos are practically similar in general construction and either one of them will act as the other when suitably traversed by an electric current, there are certain differences between the connections and accessories of a machine operated as generator and one employed as a motor. For instance, when a machine is operated as a dynamo, it is first driven up to speed until it has excited itself to the right pressure, and then it is connected to the circuit ”

“ In mechanical appliances the new world has seemed to complete the inventions begun in the old world. Such was the case with the recording telegraph, the telephone, and the electric light. But in another class of inventions America did little or nothing. It was Europe that supplied the artificial generators of electricity. The voltaic pile, the thermo-electric pile, the Daniell and Grove batteries, and the dynamo machine were creations of the old world ”

“ Replace it, and let the cylinder be again wiped; the machine is fit for use.
4. Sometimes the electric matter will not be well collected, because the machine is not sufficiently supplied with it from the earth; which happens, when the table upon which the electrical machine is placed and to which the chain or wire of the rubber is connected, is very dry, and consequently a bad conductor. In this case, the best method is to connect the chain or wire of the rubber with some moist ground, or with the iron-work of a water-pump, if convenient. ”

“ In the illustration, Fig. 32, [56] is shown a modern electric motor. It is a Westinghouse two-phase machine, of 300 horse power, of the self starting induction type, designed to operate at a speed of 500 revolutions per minute when supplied with two-phase currents of 3,000 alternations per minute and 2,000 volts pressure.
FIG. 33.—SIEMENS’ FIRST ELECTRIC RAILWAY.
The most important application of the electric motor is for street car operation. ”

“ For, while an excellent and elaborately constructed stationary steam-engine can produce but a small fraction of the energy it absorbs, a good electric engine (or electro-motor) will return seventy-five per cent of the electric energy given it by the generating dynamo. For the reason, however, that no economical means of generating large currents are yet discovered, except the method described of first burning coal, the use of electric machinery is at present restricted to certain industries. ”

“ Suppose we treat the machine as a dynamo. Bring the ends of the line wire together, thus, as we say, closing the circuit. By some external force let us cause the armature to rotate and under the influence of the magnetic field it will generate an electric current, part of which will pass through the field and part through the line circuit. We may adjust the relative amount of wire in field and line so that any portion of the current we choose will pass through the field. ”

“ Many of the troubles on a modern car are apt to be in connection with the electrical equipment—battery, lights, magneto, timer, self-starter, etc. Sooner or later, a boy who takes an interest, is apt to become more or less familiar with the principle of all these things, especially if his nerves and brain are not deadened by forced application. At any rate, this boy soon did. This led to an interest in other electrical things—the ringing of bells and buzzers about the house, and the installation of an electric motor which would run the sewing machine, or a grindstone, or a little lathe. ”

“ It takes a two-horse-power engine working an Edison or Gramme machine six to eight hours to charge them, and when charged they will keep almost any number of lamps of sixteen-candle-power going some eight hours. They are used on the Brighton and South Coast Railway, and seem peculiarly adapted to lighting by incandescence, by Swan, or Edison’s lamp. The elements fully charged may be carried any distance without losing their electric power. And the stored force may be used for charging the accumulators themselves afresh from the machine. ”

“ And when, starting from the researches of Siemens, Wilde, Nollet, Holmes and Gramme, the modern forms of magneto-electric and dynamo-electric machines began to come into commercial use, it was discovered that any one of the modern machines designed as a generator of currents constituted a far more efficient electric motor than any of the previous forms which had been designed specially as motors. ”

“ Fifth—The magnetic electrical machine enables us to convert mechanical power into heat by aid of the electric currents which are induced by it, and I have little doubt that by interposing an electro-magnetic engine in the circuit of a battery a diminution of the heat evolved per equivalent of chemical change would be the consequence, and that in proportion to the mechanical powers obtained.’ If in No 4 above we read electro-motive force for ‘intensity,’ it will be recognised as in accordance with our present knowledge of the subject. ”

“ The current obtainable from such a machine is exceedingly small, and any attempt to produce the electric currents required for lighting or other technical purposes by the use of a frictional machine is foredoomed to failure. ”

“ If we wish it to go on further we must increase the source from which the negative charge of the cylinder is derived, that is, we must charge the sphere more strongly. How are we to increase this positive charge? The most obvious thing is to increase it also by mechanical means, much in the same way as we increase the charge on the third conductor, and this is the principle on which the modern electric machines, the so-called "influence machines," work. ”

“ But, fortunately, we have faith in the measurements, of which I have already spoken, in the facts given us by Joule's experiments and formulated in ways we can understand. And these facts tell us that in electric machines of the future, and in their connecting wires, there will be little heating, and therefore little loss. We shall, I believe, at no distant date, have great central stations, possibly situated at the bottom of coal-pits where enormous steam engines will drive enormous electric machines. ”