This paper describes a method to operate a switched reluctance machine (SRM) sensorless with a precise position estimation but without the necessity of a prior known machine characteristic. When a machine is connected to the inverter for the first time, an initialization sequence is started to determine the inductance profile of the machine automatically. Within this sequence the machine is started and the inductance of all phases is recorded over time while the machine is rotating. From the data the rotor position is extracted and linked to the recorded inductance values. The data is finally merged to one inductance profile, which is used for controlling the machine. Only information about the machine configuration, the maximum allowable machine speed and phase currents must be provided. The proposed method was implemented on a test bench and verified with a 2 kW four-phase SRM using direct average torque control (DATC).