Abstract: An electrical synchronous machine is provided for a rail-free vehicle. The vehicle has drive wheels and the synchronous machine is designed to generate a torque, which propels the vehicle, at the drive wheels. The synchronous machine has a stator and a rotor which rotates around the stator, wherein the stator has a stator winding of at least three-phase construction for forming a rotating stator magnetic field, and wherein the rotor has at least one rotor winding which is designed for forming a rotor magnetic field. A method for at least partially circumferentially establishing a current-excited synchronous machine provides a rotor yoke, provides a large number of rotor poles, fastens the rotor poles to the rotor yoke for forming a rotor, provides a stator, and inserts the stator into the rotor.

Abstract: A coil unit includes ferrite cores; and a coil disposed to face the ferrite cores, the coil including a plurality of curve portions. Each curve portion is wound across a virtual straight line extending through a curvature center of the curve portion. The ferrite cores include curve portion ferrite cores disposed to face the curve portions, respectively. Each of the curve portion ferrite cores is provided such that a width of a region with a highest magnetic flux density is larger than a width of a region other than the region with the highest magnetic flux density, in a region that faces the coil, in a case where a length direction is defined as a direction in which the virtual straight line extends, and a width direction is defined as a direction perpendicular to the virtual straight line.