Life and Work of Rolf Wideröe by © Pedro Waloschek, => Contents
Although Rogowski only pursued his own scientific work and did not accept commissions for research or development, he had good connections to industry. He recommended me to the director of AEG's transformer factory in Oberschöneweide near Berlin. His name was Dr. Stern and he later became a university lecturer. This factory needed someone to develop safety-relays, to protect power plants against short circuits in high-voltage transmission lines. Shorts like this could happen for many reasons, for instance, if a tree fell on a line. I went to Berlin in the spring of 1928.
I met Mr.J.Biermanns in the AEG transformer factory. A very nice man, he held an important position as the head electrician at the factory. Among his achievements was a book on `Overshoot-Currents in High Voltage Installations' [Bi26] and he was later awarded a professorship too. I last visited him in Hanover during one of my drives through Germany at the beginning of the 1950s. He died shortly afterwards.
Together with Reinhold Rüdenberg, Biermanns had invented a relay to protect electric power plants. Rüdenberg was head electrician for the Siemens-Schuckert factory in Berlin-Siemensstadt, and as such, head of the `Scientific Department'. He was considered an authority in the field of high current technology in Germany at the time. He wrote a book about relays and was interested in the problem of linked power stations [Ru29]. We never met. The physicist Max Steenbeck with whom he submitted a patent in 1933, to which subject I shall return later on, worked in his department.
The principle behind the Biermanns-Rüdenberg relays was that the short-circuit voltage was divided by the short-circuit current and that the delay-time of the oil-switch (interrupting the current in the line) could be set proportional to the impedance (i.e., the line's resistance). If several such relays react during a fault, the nearest relay in the high-voltage transmission system will react first and thus selectively switch off the fault. The relays also had to be directional, an important fact when dealing with parallel lines. However, Biermanns' relay was rather primitive. It had a relatively long reaction-time (delay) and very poor directional sensitivity. Biermanns' assistant Otto Mayr had proposed a different construction and it became my task to develop and construct the new relay.
Otto Mayr was from Kempten, the same age as I, and we became good friends. He later developed a pneumatic switch and a physical explanation for the switching theory. He was subsequently awarded an honorary Doctorate in Engineering. His last years were spent in Schwäbisch Hall where he died in 1989.
I worked first in the transformer factory and later in a relay factory called `Dr.PaulMeyer', which had been bought by AEG.
My first years in Berlin were very interesting; it is such a stimulating city. In 1929, Berlin hosted an important international conference. I went along and heard lectures by Einstein as well as Eddington who reported on the stars' generation of energy by nuclear fusion. He spoke of temperatures of 40 million degrees.
My work at AEG was quite fascinating to me. I saw the relay as a kind of artificial intelligence as we would say today, or as a sophisticated analogue computer. During the time I developed relays I submitted a total of 41 German and 2 American patents for AEG. It was a very productive period.
At AEG I met Arno Brasch and Fritz Lange. On top of the roof of one of the factory's buildings, there was a high voltage Marx-generator with which it was possible to obtain over one million volts, and I suspect that Brasch and Lange used it to irradiate mice [Br30]. They also tried to induce some nuclear reactions, and may even have had some success, without, however, being able to provide exact proof. Brasch and Lange conducted a few other, rather hair-raising, experiments with high voltages. For instance, they wanted to `divert' high voltage from storm clouds at Monte Generoso in Switzerland, which, of course, was very dangerous.
I also met Leo Szilard in Berlin. He was a very interesting man. I remember sitting in a cafe while he told me about one of his high voltage projects. He wanted to build several transformers, one on top of the other. The lower ones were to activate the ones above in some sort of cascade circuit. Szilard had many good, although often vague ideas. He was fun to be with, a typical Hungarian. Even then he had a good relationship with Einstein. I believe that together they developed the principle for a type of refrigerator and then submitted it for patenting _ if, that is, my memory serves me right.
During my time at the AEG factory in Berlin-Schöneweide I was able to dedicate myself entirely to relay technology and was generally free of business and administrative tasks. I gave very little actual thought to particle accelerators at the time, but I did keep an eye on their development.
However one of my laboratory colleagues at the transformer factory, his name was Kujath, wanted to continue the development of the ray-transformer. We sat in the same room, he behind me, and I never saw him again afterwards. I remember explaining to him that if the magnetic stray-fields were correctly shaped, there have to be forces with which it may be possible to stabilise the electron orbits. However, according to my Aachen experiences and as I believed at the time, these forces would be inadequate for the task. This is more or less what I wrote in my thesis.
In those days I was beginning to think about a stronger way of focusing, that is, about improving the bundling of particles on their intended circular course. A practicable solution did not come to me, however, until much later. During my Berlin period I had more or less written-off the ray-transformer. This does seem rather strange to me now.
Then came the Depression in 1930 and the years that followed. I was running a laboratory and it was difficult and embarrassing to have to give notice to many of the engineers and employees. At first, all wages were halved. Mine as well, of course. After I left AEG, I sued the company and received some compensation.
Time and again I heard news about Lawrence's successes with his cyclotrons. Ernst Sommerfeld kept me up-to-date through his father. And there were other machines being developed to increase the voltages which could be generated. For example there was one at the Carnegie Institution in Washington, by Breit, Tuve, Havstad and Dahl [Br28] and another at Princeton University, by Robert J. Van de Graaff [Gr31]. The latter had gone back to an old idea which was to transport electrical charges to an isolated metal sphere by means of suitable strips. He did such a good job that his machines were copied everywhere and they were even produced by industry. I would like to note in this context that Tuve, Hafstad and Dahl were of Norwegian ancestry and that Tuve was a childhood friend and fellow student of Lawrence's.
Then, in 1932, came the first disintegration of an atomic nucleus with artificially accelerated particles. John Cockroft and Ernest Walton achieved this with a cascade-generator which only reached 400,000 volts [Co32]. Incidentally, the principle used for producing the high voltage came from H.Greinacher in Switzerland [Gr21]. Shortly afterwards, Lawrence could confirm the results of Cockroft and Walton using one of his cyclotrons. There was a lot to talk about in Berlin!
However, Hitler was threatening to take power, and I left Germany just in time before it happened. I could already sense that things would not be too good under Hitler and returned to Norway shortly before Christmas 1932.
While I was still working in the `Dr. Paul Meyer' laboratory I had had an idea for building much better relays. As mentioned before, they had already developed quite an interesting relay long before I got to the laboratory. It could determine the distance to the short-circuit. It was also called a `distance relay'. However, as already mentioned, it had many faults, was not very precise nor very sensitive. My new idea was much simpler, more robust and promised to be faster and more accurate.
I was pretty well informed about the situation in Norway and knew that the many power stations which were connected together in a so-called `Samkjöringen' (the `network') urgently required security distance relays. I also knew that a robust and simple relay would be very useful in Norway. Many electrical companies used only unskilled labour, and complicated, precision engineering was not much use to them.
First of all I selected a relatively small company which I considered suitable for manufacturing my relays. The company was `N.Jacobsen's Electrical Workshop' (NJEV) in Oslo. I spoke with the director, a Mr.Haug, and convinced him that my relays would be a good thing for him. After short deliberations we came to an agreement, and I was paid 500 Kroners a month, a pretty good salary in those days, and started work at Jacobsen's on April 1, 1933. As I had already completed all the design work for my new relay beforehand I was able to start construction immediately.
I would now like to say more about these relays, although it may only be of interest to readers who are curious about technical matters. Figures 5.1 and 5.2 show such a relay. I used a rod-shaped electromagnet as a voltage sensor which was fed with direct current via a small selenium-rectifier. The magnet's yoke had quite a large pole surface and a fairly strong constriction below. The result was an attractive force on an iron armature, which increased almost linearly with the voltage, even in the lowest region. A bi-metal would then try to pull off the iron armature.
The current-transformer for the bi-metal had a hole at the centre of the iron core which was dimensioned in such a way that the current for the bi-metal increased with the square root of the current, and the temperature rise (and consequently the bi-metal's tension) became proportional to the product of current and time. The interval within which the bi-metal pulled off the armature from the electromagnet was therefore proportional to the ratio between voltage and current, or to the `impedance' of the short-circuited line. A small hook (a roller bearing) was detached when the armature came off and this activated the high voltage switch placed on the line. It was possible to read the delay-time on a small synchronous watch and thus determine the distance to the short-circuit. The relay was cheap to make and did not require any sensitive precision engineering. But it was very accurate.
The shortest reaction-time was only two periods long, i.e. approximately 1/25 of a second. This is of great importance, since, if this time interval (the `basic time interval') is too long, the generators could get out of phase and the whole system of linked power stations would thus be in danger of collapse. I later wrote a precise description of the `distance-relay' for the Journal of the Electrotechnical Society of Vienna [Wi37] and I submitted a total of ten Norwegian patents for Jacobsen on this subject.
The relay was completed in the autumn of 1933. I then took my Ford-A on a vacation tour of England, Spain, Italy and Germany, during which I was also going to introduce my relay to the market. To my great regret I found that it was not at all easy to sell the relays. In the end the journey turned into quite an adventure. I met up with my friend Torvald Torgersen in England, and he accompanied me for the rest of the trip. Torvald fell ill on the way. We found out later that he had been infected with typhoid and I caught paratyphoid B as well. We were very lucky to survive those exertions. Torvald is alive and well today, and has a summer house on Skjelöy (near Fredrikstad) close to my sister Else's.
In March 1934, we conducted the first field tests with the relay in Norway, on a line in Vestfold. However, shortly before that, in February 1934, I met my wife-to-be Ragnhild Christiansen in Oslo. I had enrolled at Miss Fearnley's dance academy, in order to learn all the latest dances, and that is where I met Ragnhild, whose parents lived not far from us. We married on November 14, 1934 and spent our honeymoon in Stockholm.
Our three children Unn, Arild and Rolf were all born in Oslo in the years 1936, 1938 and 1941.
Ragnhild occasionally (and unofficially) worked at Jacobsen's during the summer of 1935 and helped me to build and set up the relays. I remember one evening, I was completely absorbed in my calculations and, suddenly realising how late it was, I went into the anteroom where Ragnhild was working and said, "Miss, you may go home now". I had completely forgotten that we were married! And Ragnhild has not forgotten the incident to this day!
In the spring of 1935 we installed the first of about 30 distance relays in the Norwegian power distribution network. Ragnhild and I would often drive around together in my Ford-A and we did almost everything ourselves, from setting up the relays in the factory to installing them in the power stations. The relays have all been very successful and correctly switched off during short-circuits [Wi37]. Quite a few of them are probably functioning today.
I think it was in autumn 1937 when six companies were invited by the `Samkjöringen' to propose a new network scheme (including protection relays) for the Norwegian power stations. The submitted schemes had to be supported by cost estimates. The six companies were Siemens, AEG, Brown Boveri, the Compagnie des Compteurs, Westinghouse and our little company, Jacobsen. We won hands down. My relays were much faster, much more precise, much stronger and furthermore, they were cheaper than those of the competition.
Then, in 1937, something unusual happened. A gentleman came to see me. His name was Eivind Hansen, he was the director of the large transformer factory `National Industri' in Drammen and he offered me a job. The factory belonged to the American Westinghouse group which also had an office in Oslo. I was given the impression that I would become Hansen's successor and accepted.
However, I first had to find a successor for my own work at Jacobsen's and then teach him all there was to know about the relays. I found a good man and all went well. Years later the Jacobsen company got into a mess with current limiters or household current-meters. They lost a great deal of money and eventually had to declare bankruptcy.
I spent three years with National Industri, but it was not a happy time. Most of my work consisted of selling Westinghouse transformers and high voltage protection devices (a type of `Thyrit-protection' against over-voltages, travelling waves and similar things in power lines).
While I was with Jacobsen's I published eight papers, with National Industri not a single one, except perhaps the write-up of one longish lecture on relays which I gave during a Nordic conference of engineers in Copenhagen in 1937. That was typical. With National Industri I was on ice, practically dead. Of course I gave a few lectures on high voltage protection devices, but that was nothing special.
Then, in September 1939, War began. Because of the distance-relays, I had had some contact with `Norsk Elektrisk og Brown Boveri' (NEBB). This company employed an engineer named Styff who died during the first days of the War, and I suppose that NEBB's director Solberg spoke with Eivind Hansen about me, because shortly afterwards Solberg offered me a position and I replaced Styff in June 1940.
As Finn Aaserud and Jan Vaagen later told me, Styff had been present during my 1937 relay lecture in Copenhagen, so he was aware of my interests. This had been shortly after I had started at National Industri. Finn Aaserud also told me that Niels Bohr gave the introductory lecture, which I certainly must have heard, but cannot remember at all. Bohr's lectures were often a little difficult to understand. A tour of the Bohr-Institute was laid on following his lecture and I definitely wasn't present then. Being in Copenhagen with my wife, I guess I had other things to do - we were probably sight-seeing.
See Ranghild Wideröe and Rolf Wideröe in that time in Figs. 5.3 and 5.4.
At the time I was close to the `Physics Association' which was founded in autumn 1938 by students, university lecturers and other interested parties in Oslo. I had managed to persuade National Industri to give financial support to the association, I think they donated about 5,000 Kroners. However, the association experienced financial problems during the War.
According to my friend Olav Netteland's reliable memory,
the association was also given a few hundred Kroners to start
a magazine. The first and very modest edition was produced in
the summer of 1939. It was called `Fra Fysikkens Verden' (in
English: `The World of Physics') and it still exists today. Until 1956 it
was edited by the theoretician Egil Hylleraas, professor at
Oslo University. The 54th year's issues appeared in 1992, although by
then it had naturally become a somewhat more sophisticated
production. I still subscribe to it. When we started the magazine we
had counted on financing it with advertising which the printer
had arranged for us. Regrettably the clients did not pay and for a
while there was no money left with which to continue. In the
end however, we managed somehow.