Abstract: A process and an arrangement are described for determining reference positions for planar hybrid stepper motors having a stator which is provided with a structure and a rotor which is supported thereon in air bearings. The process includes the following steps: The rotor is set down on the stator and the air supply for the air bearing is switched on. The rotor is brought into an alignment position in a working connection with at least two defined, stationary mechanical stops or with displacement-free electrical contacts manually or by mechanical or electrical auxiliary device or in a self-propelled manner. The air supply for the air bearing is then turned off in order to fix the rotor in this alignment position and the rotor is then so supplied with current in sequence in a defined manner and the air supply to the air bearings switched on in such a way that the rotor is brought from the alignment position into a reference position which is aligned with respect to the stator structure.