Abstract: A d.c. motor control system includes a pair of armature windings mounted on a single rotor or on a pair of mechanically coupled rotors, and a field winding or windings. The system includes switch means operable to effect a change in the electrical connections of the armature windings to a pair of electrical supply terminals and means for effecting variations of the current flowing in the field winding or windings.

Abstract: A wheeled vehicle includes a wheel carrying axle upon which the weight of the vehicle and its load is carried through the intermediary of a spring. The spring is coupled to the axle by means of a mounting unit which includes a pair of spaced mounting plates and also a pair of spaced supporting plates which are disposed in spaced relationship relative to the mounting plates. Interposed between the support plates and mounting plates are sensing elements and the support plates and mounting plates are clamped together by means of bolts. The upper sensing elements are subjected to the clamping force together with the weight of the vehicle and its load, whilst the lower sensing elements are only subjected to the clamping force. The sensing elements are connected into a bridge circuit.