Charles Proteus Steinmetz was born April 9, 1865, the day Lee sent a message to Grant announcing his willingness to surrender, thus ending the American Civil War. Steinmetz lived in the U.S. until the Jazz Age was in full swing. He was a consummate mathematician and electrical engineer. The great achievement in his life work was in finding ways to simplify and rationalize mathematical interpretations of electrical phenomena, both in nature and those that were human made.
Steinmetz was born in Breslau, a province of Silezia, Germany. As a youth he excelled in mathematics and physics. He moved on to the University of Breslau and had nearly completed studies for a Ph.D. when disaster struck. German police initiated an investigation focusing on some articles he had written for a socialist newspaper. (Steinmetz throughout his short life strongly sympathized with the downtrodden, always opposing racism and oppression.)
In 1882, facing arrest and prosecution for his progressive ideals and activities, he relocated to Zürich, Switzerland. Soon he landed in New York City and then Yonkers. He joined a firm that built electrical transformers and related equipment. The young Steinmetz studied magnetic hysteresis and published writings on the subject, earning immediate recognition in the field.
Hysteresis is a somewhat enigmatic topic. To understand it, you have to make sense of the idea that an inanimate object, such as an electromagnet, can have memory. Consider a common device, the thermostat. It switches on and cuts out at two disparate temperatures, the purpose of the different turn-on/turn-off points being to avoid chattering or fast cycling. Thus we see that the output does not solely depend upon the input. The output also varys according to its internal state or history. Where the phenomenon was important to Steinmetz and his colleagues was in the realm of ferromagnetics. Today we see hysteresis in such diverse fields as aerodynamics, economics and biology. The common rubber band exhibits hysteresis because of internal friction.
The effects of hysteresis can be graphed. The effect appears as a loop with separate curves that join at limiting cases. Hysteresis is relevant to magnetics because when an external field is applied to a magnetic material, that material becomes magnetized and remains so even when the field is removed. In that sense a simple magnet may be said to have a memory.
In the years that followed his move to the U.S., Steinmetz made great contributions in the fields of alternating current, electric motors and generators, steady-state analysis and electrical transients. For a short time he worked with Thomas Edison before joining a new firm called General Electric, in Schenectady, N.Y. There he found a home, becoming a well-known American icon. A brilliant mathematician, he simplified difficult calculus procedures with his use of the letter j to designate the imaginary square-root-of-minus-one operator in waveform analysis. (In electronics, i was already taken — it signified electrical current.)
Steinmetz was a lucid communicator. English was not his first language, but consider the opening paragraph of Theory and Calculation of Electric Circuits (McGraw-Hill, 1917):
“When electric power flows through a circuit, we find phenomena taking place outside of the conductor, which directs the flow of power and also inside thereof. The phenomena outside of the conductor are conditions of stress in space which are called the electric field, the two main components of the electric field being the electromagnetic component, characterized by circuit constant conductance, L, and the electrostatic component, characterized by the electric circuit constant capacity, C. Inside of the conductor we find a conversion of energy into heat.”