Zoellner writes in 1885: "The history of electromagnetic motors ends in its childhood, or rather, goes along with the history of the dynamo." Timetable 1885 - 1893: The three-phase system and the induction motor 1882-1889 The future DC motor does not emerge from the developments of Jedlik, Jacobi, Davenport, Davidson, Page or other early inventors, whose designs are ultimately proven to be inferior, but from Siemens's dynamo machine. With Ritchie's commutator, the drum armature of Siemens and Hefner Alteneck and the lamination of the magnetic circuit all important design features of modern electric DC motors are known.
He does not, however, pursue his idea any further. In 1875, he reduces the problem of eddy currents by using iron wires instead of solid iron for the magnetic core.Īuguste Pellerin (Franzose) proposes to subdivide the iron core into several separate, mutually insulated steel sheets in order to avoid eddy current losses.
This improves the double-T anchor machine, which can now also produce a smooth DC voltage. He wraps wire around a cylinder-shaped anchor. Gramme's construction, however, is no longer used today.įriedrich von Hefner-Alteneck (German), a close associate of Werner Siemens, starts development of the anchor drum motor. In subsequent years, Gramme's machines are in strong competition Siemens' double-T armature machines. Zénobe Théophil Gramme (Belgium) solves the problem by the invention of the anchor ring, which produces a smooth DC voltage. The Siemens double-T armature has the disadvantage of producing a pulsating direct current. Siemens develops the dynamo-electric machine based on the double-T armature.įinally, a powerful electric generator is available and the advent of electricity begins. These equations are still valid today and fully describe the theory of electrical engineering. Around 1882, Oliver Heaviside (British) uses vector calculus and reduces 12 of the equations further to just 4 equations with 4 variables. James Clerk Maxwell (British) summarizes all the current knowledge of electromagnetism in 20 fundamental equations.
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