The motor has no magnetic flux parallel to the movement direction in its passive part (5). The passive part is located between the opposing poles of the active components. The passive part is composed of poles (6) and ridges (7). The normal forces between the active and passive parts are opposed and equally large when the current through the coil (3c) is at its maximum. The air gaps (11,12) are the same size, due to the motor construction. Hence the forces cancel each other and do not strain the mounting between the active and passive parts. In the first mode the coil currents are set between zero and maximum. The control circuitry positions the machine in a first mode, and then tractive effort is developed in a second mode.
