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The Age of Electrical Enlightenment

The advances in electrical work were exciting for those in the field, but without a practical application, they were useless to the general population. When we embarked on our historical journey to unite the past with the present, we wanted to demonstrate how technology has transformed the times during EC&M's 100 years of service to the electrical industry. But we soon realized that before we could

The advances in electrical work were exciting for those in the field, but without a practical application, they were useless to the general population.

When we embarked on our historical journey to unite the past with the present, we wanted to demonstrate how technology has transformed the times during EC&M's 100 years of service to the electrical industry. But we soon realized that before we could delve into the tremendous advances the electrical industry has undergone and changes it has seen over the last 100 years, a history lesson is in order. Without a discussion of the early electrical pioneers of the 18th and 19th centuries and their revolutionary experiments, inventions, and technological breakthroughs, our story would not be complete. How did we get to 1901? The following abridged review of the evolution of electricity demonstrates how very deep our electrical roots run.

Without knowing it, our ancient ancestors observed the effects of electricity for centuries. The strange electrical flames burning at the top of a ship's mast that came to be known as St. Elmo's fire bewildered many a medieval sailor. Unfortunately, there were no attempts to explain these strange occurrences until the early Greeks asked “why?” about the world around them. In fact, it was the Greeks who first questioned the actual nature of the attraction between amber and lodestone. However, neither their greatest minds nor those of the Roman empire that followed added anything significant to man's understanding of electricity and magnetism.

The Renaissance saw the cracking of the unquestioned foundations of man's limited knowledge of natural law. And Roger Bacon struck the first blow. Although his observations on amber and lodestone lacked depth, Bacon was the first to attempt to explain the phenomenon of magnetism. Peter Peregrinus, a 13th century philosopher who wrote the first extant treatise on the properties of magnetism, experimented with what he called “terrella,” a round lodestone. From these experiments, he built several compasses, each showing the power and attractive force of lodestone.

Arguably, one of the most important discoveries in the history of electricity was that of the existence of a connection between electricity and magnetism. It was the inventions and discoveries of those inquisitive and diligent pioneers who toiled throughout the 1600s and 1700s that pushed electrical discovery forward. Let's review the work of some of these early pioneers.

Otto von Geuricke. While his name is not overly familiar to the general public, Geuricke holds the honor of constructing the first electrical machine in 1660. He described it in his book Experimenta Nova Magdeburgica, published in 1672. His machine was basically a sulfur ball revolving on a shaft. He formed the ball by first pouring molten sulfur into a spherical glass container. After the sulfur cooled, he shattered the glass. Then, Geuricke inserted an iron shaft into the ball and mounted the assembly on the bearing supports of a wooden frame. While revolving the sphere, he applied his dry hand to it, which electrified the sphere. It would then attract paper, feathers, lint, and other light objects.

Geuricke noted small sparks in the sphere's discharge and heard a crackling sound. This was the first time anyone had actually seen and heard what (up to that time) was believed to be a gentle attractive force.

Geuricke also took the first tentative steps to try and transmit this power by placing a linen thread in contact with the electrified globe. While the distance was only a little more than a yard, it proved to be the foundation for Stephen Gray's transmission of electricity across 250 yd of linen thread some 50 years later.

Stephen Gray. Although we know very little of this English inventor, he was probably born in 1666 or 1667 in Canterbury, England and died in 1736. His main claim to fame was the extension of the electrical property of one object to another some distance away. The distance increased, through experimentation, from 34 ft to 80 ft to 750 ft and finally in 1730, to 866 ft. In 1732, Gray and fellow inventor Granville Wheler carried out experiments to increase their understanding of the properties of induction. They extended parallel lines with a 1ft separation and concluded that the electricity carried by a short rod or a long line to a distant object could also be made to act on another separated rod or line.

Pieter van Musschenbroek. In 1746, this Dutch professor of experimental physics developed a device for accumulating or storing one or more charges of electricity: the Leyden jar. The jar was part of van Musschenbroek's assembly of various mundane items, such as a gun barrel hung by silk threads and connected to water in the Leyden jar with a brass wire. The gun received electricity via a person touching it and a rotating glass globe. Dr. John Bevis made improvements to the basic Leyden jar by adding a thin sheet of lead or tin foil to the jar's outer surface. He also included a glass plate with foil on each surface to act as an accumulator of electric charges. This was the earliest form of a plate condenser. Dr. William Watson, along with van Musschenbroek, found that the thinner the intervening glass between the metallic coatings and the larger the area of coatings, the stronger the charge from the jar.

Dr. Martinus van Marum. This Dutch inventor (1730-1857) designed the then-largest electrostatic generator in the 1700s. Built by an English instrument maker in Amsterdam, the machine consisted of two parallel rotating glass discs, each 65 in. in diameter mounted 7½ in. apart on a single yard-long axle. Compound cranks rotated the discs, with positions for two operators working simultaneously.

With the machine, van Marum drew 2-ft-long sparks that affected an electrometer 40 ft away from the machine. He also conducted tests on the fusion of metal wires as well as the effect of battery discharge on different metals and alloys. From these experiments, van Marum concluded that copper was the best material for lightning conductors and lead the worst.

With the machine, van Marum also observed spark branchings between the massive electrodes and related their direction to the charge (positive or negative) of the electrode.

Benjamin Franklin. The statesman's study of electricity is legendary. The figure of Franklin flying a kite in a lightning storm is synonymous with the discovery of electricity. Not as commonly known is his experimentation with glass friction generators and Leyden jars. Through these experiments, he developed the concept that “electric fluid” (in some unknown way) attracted materials that did not contain the fluid. Franklin later modified his theory to include repulsion between two objects that either had the fluid or lacked it. Basically, Franklin theorized that the electric force was an imbalance of an otherwise normally neutral state. Electricity was really “vitreous” electricity and positive. Its absence or depletion was “resinous” and negative. Franklin also offered simpler terms, replacing the older terminology of “electric per se” with the term “conductor” and “nonelectric” with the term “non-conductor.” Franklin's concept led to an easier understanding of the process of conduction as well as the operation of early friction machines and the Leyden jar. Even today, it gives us a basic description of electricity and its associated phenomena.

Not until 1749 did Franklin theorize that lightning was an electrical display. This is what generated his international fame. In letters to Peter Collinson and other members of the Royal Society, he proposed the nature of lightning and included supporting experimentation and a dissertation on the lightning rod. Franklin gained legendary fame with his “Philadelphia experiment,” the term used for the testing of his lightning rod.

Building on Franklin's conceptual base and employing a selection of greatly improved machines, a wide range of scientists began to test new theories in earnest. They focused on the medical, biological, and chemical effects of this “electric fluid.” They thought the “fluid” could cure a variety of diseases as well as break water down into two gases.

Allessandro Volta. In the early 1790s, Italian Luigi Galvani found that the “fluid” caused muscles to twitch. This caused his countryman, Alessandro Volta, to propose an alternative concept that involved electric differences between pairs of metals, which led to his invention of the electric pile. The name provides a fair description of the device; it consisted of a pile of pairs of metal (zinc and copper) discs, each pair separated by moistened cloth. Volta published details of his pile, or battery, in 1800 (see photo, right).

Volta's invention was notable for its steady production of current. It was also easily transportable. However, it didn't have a high enough potential (voltage) to produce sparks. Although it did little to advance the study of electricity, it proved useful in other disciplines. Researchers of Volta's time began using the pile to break down numerous compounds into their constituent elements and verify the electrical theories of chemistry.

Volta believed the contact between unlike metals through conducting water produced electricity. Many great scientists of his day agreed. But others, like Michael Faraday, insisted the source was in the chemical action: the zinc being eaten away, hydrogen bubbling out at the copper disc, and a steady stream of energy being freed.

A closer look shows that Volta was wrong with his contact theory. Why? It violates the law of conservation of energy (making something out of nothing). Of course at that time, the law was not universally understood.

Volta was also active in the field of electrostatics, developing what he called the “perpetual electrophorus.” This was a machine that operated on the principal of electrostatic induction, or “influence.” In fact, it operated on electrical charges produced at a distance.

Jean-Baptiste Biot. Starting out as a professor of mathematics at the college of Louis-le-grand in Paris in the early 1790s, Jean-Baptiste Biot gained recognition through an important discovery. He found the intensity of a magnetic field set up by a current flowing through a wire varies inversely with the distance from the wire. We now know this tenant as Biot-Savart's Law, one of the basic fundamentals of modern electromagnetic theory.

Hans Christian Oersted. This Danish professor accidentally stumbled upon the link between magnetism and electricity in 1820. Lecturing to his students, Oersted was demonstrating the heating of a wire by an electric current. As Oersted passed current through the wire, he saw the needle of a nearby compass swing to one side. When he stopped the current flow, the needle swung back. His curiosity piqued, Oersted began a series of experiments to confirm this intriguing phenomenon. He theorized the magnetic effect in the space surrounding the wire was a “conflict of electricity.” He saw this conflict as acting only on particles of magnetic matter, which were resisting the magnetic field. This was the first step in explaining electromagnetism, and it opened the age of electric power.

Andre Marie Ampere. Within a few weeks of Oersted's announcement, Andre Marie Ampere, a French aristocrat, established a new science: electrodynamics. The turning point for Ampere was the publication of Oersted's paper on electromagnetism.

After reading the paper, Ampere experimented further, recorded the results, and translated them into mathematical formulas. In September, 1820, he submitted his first paper on electromagnetism to the Academy of Science in Paris. In it, he examined and explained how Oersted's experiments depended on the position of the wire and compass.

Ampere did a number of other experiments that resulted in many important discoveries. For example, he found two wires carrying current in the same direction attracted one another while those carrying current in opposite directions repulsed each other. Ampere also found a wire twisted into a spiral around a compass needle produced a stronger effect than a straight wire located in the same proximity. The needle's reaction increased as the number of wire turns increased. These phenomena led to Ampere's invention of the galvanometer.

Ampere's work went further; he completed the circuit loop and continued the winding of the conductor into a large number of turns in the same direction. This further multiplied the effect on the needle and resulted in the development of the electrodynamic solenoid.

In evaluating Oersted's work on the relationship of current and magnetism, Ampere realized this relationship could be used to send messages. He suggested using a pair of wires and a magnetic needle for each letter of the alphabet. Basically, his theory involved the opening and closing of the desired circuits for the desired letters, which formed the basic principle of the electric telegraph.

Georg Simon Ohm. In 1825, Ohm was completely convinced that the current flowing through most materials is directly proportional to the potential difference applied across the material. But, in his first published paper, he did not include this theory. Instead, Ohm focused on electromagnetic force in a wire and its decrease as the length of the wire is increased.

Later in 1826, Ohm published two additional papers in which he gave a mathematical description of conduction in circuits modeled on Fourier's study of heat conduction. Again, Ohm deduced the contained information from his experimental evidence. The second paper's importance stemmed from its stated laws explaining much of the work of others on the subject of galvanic electricity. Many consider this second paper as the first step in Ohm's comprehensive theory known as Ohm's Law, which appeared in a book he published in 1827.

Michael Faraday. American Joseph Henry used several windings of insulated wire to build electromagnets capable of lifting thousands of pounds (see drawing, bottom left on page 6, of the electromagnet apparatus Henry made at Yale, ca. 1831). In 1820, Englishman Michael Faraday showed how to use this relationship to produce motion. He built two devices to produce what he called “electromagnetic rotation,” or a continuous circular motion from the circular magnetic force surrounding a wire.

In 1831, Faraday began an even greater series of experiments that led him to discover electromagnetic induction. According to his research, the electromagnetic effect of current in one wire induces electricity in another wire. Faraday's induction ring was the first electric transformer.

In a second series of experiments that same year, Faraday discovered “magneto-electric induction,” or the production of a steady electric current. By attaching two wires through a sliding contact to a copper disc and rotating the disc between the poles of a horseshoe magnet to generate a continuous direct current, Faraday constructed the first generator.

Faraday's experiments (and their description in his paper titled Experimental Researches Into Electricity) prompted a young Frenchman named Hippolyte Pixii to build an electric generator. It was similar to Faraday's except that it used the rotary motion between magnet and coil rather than Faraday's linear (back and forth) motion. The generators used in today's power stations are direct descendants of Pixii's machine.

Faraday continued to experiment, and in 1832 he proved that the electricity induced from a magnet, voltaic electricity produced by a battery, and static electricity were all the same. Also known for his significant work in electrochemistry, he developed the First and Second Laws of Electrolysis.

Other advanced thinkers benefited from Faraday's work. James Maxwell was able to postulate an exact mathematical theory for the propagation of electromagnetic waves because of Faraday's descriptive theory of lines of force between bodies with electrical and magnetic properties. In 1865, Maxwell proved mathematically that electromagnetic phenomena move as waves through space at the velocity of light. This formed the basis of radio communications, which Hertz confirmed experimentally in 1888 and Guglielmo Marconi developed for practical use at the turn of the century.

The advances in electrical work were exciting for those in the field, but without a practical application, it was useless to the general population. America's Samuel Morse and Alfred Vail, and Britain's Charles Wheatstone and William Cooke found a way to show the usefulness of electricity to the masses with their development of the electromagnetic telegraph in the late 1830s. The device used batteries to produce electric current, wires to conduct the current over long distances, and electromagnets to produce an effect at one end when someone closed a switch at the other. To operate with low levels of electric current, the inventors used magnets with several windings. This countered the problem of lost energy due to the long lengths of conducting wire and the resulting appreciable resistance to the flow of the current. The inventors understood that in a long electric line it's better to have a relatively high voltage and a low current.

The inventors used batteries because Faraday's generator (still in its very primitive state) was very inefficient. In fact, except for some very specialized applications, even the best generators up through the middle of the 1800s weren't very practical. It wasn't until 1866 that conditions changed. Charles Wheatstone and Werner Siemens (working independently) revolutionized the generator by building it with electromagnets in its field. Siemens' discovery was what he termed the “dynamo-electric” principle. Basically, he built an inductor in which the ‘H armature’ rotated, with only a narrow gap, between the pole shoes of a soft-iron electromagnet. The current generated in the rotating armature was used at the same time as the exciting current for the field magnets. The benefit of this was that the residual magnetism of the soft iron was sufficient to initiate the mutual building of armature current and magnetic field. The innovation allowed some portion of the generated current to be fed back into these field magnets. Wheatstone and Siemens believed there should be enough residual magnetism in the field magnets for the generator to function properly from a dead start right up to full capacity.

Zenobe Gramme improved on their design and constructed the first self-excited dynamo, allowing researchers to think about its practical applications and large-scale use of electric power. By the mid-1870s, electricians were applying these new technologies and lighting the streets of Paris, London, New York, and Cleveland, usually with lights invented by Charles Brush (see depiction, top left on page 6, of the streets of New York City, ca. 1880, lighted by Brush electric arc lamps).

Brush arc lights were the result of Brush's determination to improve the basic elements of arc lighting: the dynamo, carbon rods, and rod-feeding mechanism. He also provided innovations such as the double-carbon lamp and the automatic constant-current regulator.

Thomas Edison. Advances in electrical technology had yet to have an impact on the homeowner until Thomas Edison used ideas from large-scale power distribution to develop a less powerful incandescent lamp people could use indoors in 1879. However, inventing the light bulb wasn't enough — he had to introduce it to the masses (see photo, top right on page 6, of Edison's paper-filament incandescent lamp used in Menlo Park, ca 1880). He shrewdly promoted his invention by setting up a central generating station at Pearl Street in lower Manhattan in September 1882 (see drawing, center right on page 6, of Edison's large dynamo electric DC generator, ca 1881). It wasn't long before everyone wanted the benefits of electricity. So by the mid-1880s, several towns were pushing for electrification, mostly for lighting purposes.

Almost all of the resulting generating stations were relatively small and capable of delivering power for only short distances, because Edison's patented 200V, 3-wire, DC system (+100V and -100V around a neutral wire) was only efficient for about a half mile. Researchers theorized that power could be transmitted at higher DC voltage and then reduced to 100V at the receiving ends in homes, but the tools and equipment necessary for such a job didn't exist. They also proposed using high-voltage motors to drive low-voltage generators at the generating stations, but most discounted this solution because of its expense.

Another potential solution called for replacing direct current with alternating current. Generating stations could transmit high-voltage AC power, and then the transformer, a relatively new device, could reduce the voltage at the receiving. However, a practical AC motor had yet to be invented, so it didn't make sense to create a whole new power distribution system strictly for residential and street lighting.

Nikola Tesla. As the great minds of America and Great Britain wrestled with the elusive idea of efficient transmission and distribution over long distances, it was a 22-year-old electrical engineer in Budapest, Hungary who solved the mystery (see photo, center left on page 6, of Tesla with one of his many inventions). While walking through a park reciting poetry, Nikola Tesla was struck with a vision of an AC induction motor. Without pencil or paper, Tesla was forced to draw his discovery in the dirt with a stick or risk forgetting its structure. This drawing would revolutionize electrical transmission. (He later presented this diagram on paper to the American Institute of Electrical Engineers.)

Imagine a motor consisting of an inner magnet with poles perpendicular to the axle and surrounded by a second horseshoe magnet mounted to an independent axle. By magnetic attraction, turning one axle will force the other to turn as well. However, Tesla's design was somewhat different. He replaced the outer magnet with two sets of stationary electromagnets, each supplied with alternating current from sources 90° out of phase. The resulting phase difference created a rotating field that the inner rotor followed. This was Tesla's conception of the AC induction motor: An alternating current machine that could generate electricity more efficiently.

In 1888, the existing AC systems were single-phase, with voltage and current undergoing regular reversals. Tesla used a multiple-phase generator to produce two or more currents at the same time, with overlapping phases, creating motors capable of 2- or 3-phase operation.

As you can see from this overview of the history of electricity, the progression of early electrical technologies was driven by much more than inventions. It was the men, their vision of the future, and their tireless commitment to the intangible concept now known as electricity that fueled this story of enlightenment and discovery. What began centuries ago with a simple stone of amber and the inquisitive mind of a deep thinker evolved into one of the most powerful industries in the world. We commend these early electrical pioneers for their genius, insight, and perception, for creating our profession's rich heritage, and for laying the groundwork for one of the most remarkable industries in history.

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