Patent GB-190812738-A (GB)
Title: Improvements in and relating to Electro-magnetic Power Velocity Ratio Devices particularly applicable for Driving Automobiles and the like.
Inventor: MIDGLEY ALBERT HENRY
Filed: 1908-06-13
Granted: 1909-06-14
Abstract: 12,738. Midgley, A. H., and Vandervell, C. A. June 13. Motor road vehicles.-Apparatus for transmitting power electrically with a variable velocity ratio, particularly applicable to automobi'es &c., comprises a pair of concentric armatures with a single set of field magnets arranged between them, one element of the apparatus being stationary and the other two connected respectively to the prime mover and to the load, the control both of the generator and of the motor elements being preferably effected by adjusting the brushes One form of the apparatus, in which the motor armature is the stationary element, is shown in Fig. 1. The outer armature c is supported in a stationary casing a, and comprises a series of coils connected to a commutator d. Mounted in bearings e in this casing is the field magnet structure f connected to the driven element. The prime mover drives a shaft i<2> connected to the central shaft k, which carries the generator armature l having its coils coupled to a commutator m. The generator brushes are carried in a sleeve t<1> loose on the shaft k and rotating with the field structure f. The brushes may be adjusted relatively to the field magnets by means of a hand-lever w operating a collar v which carries a pin u<1> engaging an inclined slot u in the sleeve t' and a parallel slot v<1> in the field structure. The motor brushes o are carried on a plate which, by means of axial pins q, is in driving connexion with a disk i engaging with the field structure by means of a radial pin q<1>. The position of the brushes is adjusted by the handlever s moving the disk i and causing the pin q<1> to move forward in the inclined slot r. The disk i forms the internal member of a friction clutch which is adapted to give a direct mechanical drive when the brushes are suitably adjusted. When the lever s is in its mid-position and the lever w in its left-hand position, no current is generated in the armature l, and the driven mechanism is stationary. If the lever w is now swung over towards the position shown, the brushes are moved into such a position that current is generated in the armature l and passes through the field magnets to the motor armature c. The armature l tends to drag the field magnets, and the fixed armature c exerts a thrust thereon in the same direction, the torque gradually increasing as the lever w is swung over. To increase the speed of the driven shaft, the lever s is moved from the mid-position towards the right, so that the armature c exerts less force and the speed of the magnets increases until it is practically equal to that of the armature l. The driving and driven shafts are then mechanically connected by the friction clutch i. The direction of motion is reversed by moving the lever s over to its left-hand position, thereby shifting the motor brushes through the pole angle, and causing the current in its armature coils c to flow in the opposite direction. The thrust exerted by the armature c is now in the opposite direction and overcomes the pull of the armature l. Any other control system may be used for the motor and generator, for example, the motor armature may be gradually short-circuited so that the field magnets f follow the armature l with slight lag. Any mechanical reversing-gear may be used instead of the electric reversing - arrangement described.