Beginnings

In 1936 Dipl.-Ing. Walther Hans Bender, the founder of the company, began his work as an inspector for electrical power systems in open pit and underground coal mines in Germany.

The problem of 500 V three-phase systems inspired him to start development work in the field of earth fault monitoring in 1937.

Two years later Walther Hans Bender's work culminated in his first patent, an "insulation monitoring device and earth fault location system for three-phase systems, today known as A-ISOMETER®.