"A marriage of theory and practice"

Controlled frequencies

Adolf Leonhard began his career in 1923 at the Siemens-Schuckert works in Berlin. There he was first placed in charge of planning large-scale technical machinery, but was soon assigned to work on solutions to particularly tricky technical problems such as controlling the number of revolutions per minute in asynchronous motors. Two years later he changed to conducting tests and experiments in the dynamo works, where he investigated well-known practical problems. Three years later he moved again, this time to the assembly section and spent eight very interesting years during which he worked almost throughout the whole of Europe and learned to deliver excellent results within strict deadlines.

His appointment to the Stuttgart College of Technology in 1936 temporarily put an end to his work in industry. In 1945, Leonhard founded his own company in his search of a new field of activity. Here too he remained true to his interests and first developed a frequency controller, which was used in the first radio broadcasts in Germany after the war. At the time broadcasters were struggling to cope with irregularities and frequency fluctuations within the three-phase power network that was under reconstruction. These fluctuations were so large that pieces of music played from tape were so distorted as to be unrecognisable. Leonhard developed actuators to keep the frequency of the current constant and thus supplied the broadcasters with a solution to their problems.

His firm, "Leonhard Actuator Engineering", became a successful medium-sized company. Leonhard did not retire from managing the company until 1973.