The Beginning
The beginning was fascination! A strange effect was noticed, and then step by step, attentively and scrutinizingly further observed, anylized and concentrated in the right sequence into an experiment of significance.
Science has to be cool and precise, but behind that it was burning, eager and passionate, and that’s exactly what it still is.
Human life is not free to fly, it must build an engine or a helium balloon, it feels strongly the urge to rise. To be more than gravity dictates, to develop technology, to stretch towards it and to define at the end a confortable life.
This is the beginning as ever.
It was 1821 …
There were some people who had the time and money to take a closer look at the world. To open their eyes and investigate every new unexplained behavior. It was an exciting time, everything was new and there was so much to discover.
Oersted, Faraday, Ampère are just a few jung people, and they knew each other, wrote to each other to exchange their thoughts – a lively and exciting world.
The First Electric Motors in History
Around the same time, Ampère and Faraday built the first electric motor. Faraday had a needle rotate around a fixed mounted bar magnet or the bar magnet rotate around the needle, but Ampere had a freely movable bar magnet rotate around its axis.
Both devices are unipolar motors (direct current, no commutator), but Ampère ‘s construction conceals the paradox that Faraday later described (in the generator principle). Ampere’s construction is therefore the first unipolar motor based on the paradox (no visible force acting on the magnet that generates the magnetic field).
Picture of Faraday’s motor …
Picture of Ampère’s motor …
The Try to Explain
Ampère and Faraday exchanged letters on what causes the rotation of the bar magnet in Ampère’s construction. Ampère held firmly to Newton’s 3rd law of “Actio = Reactio”, so Faraday’s explanation was not enough for him. He was looking for the counter-torque, which he detected in the counter-rotating mercury in which the bar magnet was floating.
More information on this issue can be found here: Ampère’s motor: its history and the controversy regarding its operation
The Opposing View
Faraday’s explanation was that the magnetic field in the bar magnet causes the force on the electrons of the current flow, which results in the rotation. For Ampère, however, it was clear that this would violate Newton’s 3rd law, so he looked for another cause. To this day, there is no consensus on an explanation.
The Open Question
The answer …