Electric motor and a method therefor

An electric motor, wherein the armature is driven by an exciting field produced by exciting windings of the stator, comprising a control means for determination of a position of an armature in relation to a stator of the motor, in the case of which for the determination of the relative position the armature is excited by the exciting field to perform an oscillating movement, whose progression is detected by a position measuring means for measurement of the positions of the armature and is evaluated by the control means for determination of the relative position, wherein:

• the control means is designed for designation of a target value signal, applying for a target oscillation, to a commutation means for cause flow of current through the exciting windings;
• the control means is designed for altering a actual commutation offset value in the commutation means within a value range, which is substantially equal to a distance apart of two adjacent poles of the armature, the designating commutation offset value defining an assumed position in relation to at least one exciting winding of the stator;
• the control means is adapted to cause the flow of current through the exciting windings on the basis of the respective designating commutation offset value and of the target value signal so that the armature is driven to perform an oscillation movement corresponding to the target value signal;
• and
• the control means is adapted for the determination of at least one actual commutation offset value, at which the amplitude of the oscillation movement is near its maximum.