Patent GB-189718717-A (GB)
Title: Improvements in and relating to Controllers for Electric Motors.
Inventor: SHORT SIDNEY HOWE
Filed: 1897-08-12
Granted: 1898-05-14
Abstract: 18,717. Short, S. H. Aug. 12. Motors, controlling.-Consists of a controller for motors whereby sparking between the stationary and movable contacts is prevented in changing the relation of the motors from series to series-parallel and parallel, and with or without resistances in circuit. Within a casing A is a shaft B operated by the controller hand-lever B<1>, which can be turned to any position l<3>, l<4>, l<5>, l<6>, &c. Upon the shaft are three insulated sleeves C, D, E, each carrying segmental contacts H', H', H<3>, h<3>, h<4>, H<4>, H<5>, H<6>, H<7>, H<8>, H<9>, which can engage with fixed contacts I<1>, I<2>, I<3>, P, I<5>, I<6>, I<7>, I<8>. These contacts are connected up to the resistances R, r, motors M, m, trolley T of the car, and make and break contact K. Each different position of the controller handle causes a different set of contacts to become engaged to effect the desired combination. The contact K is automatically made and broken by an arm J which is operated from discs N, P, Q, loosely mounted upon the shaft B. A latch S normally locks the arm J out of engagement with the contact K. By means of this arrange. ment the motor circuit is initially broken by separating the arm J and contact K, and sparking at the other contacts is prevented. In a modification, the controller is formed of two parts, one for forming the various combinations in the motor circuit and to cut-in and cut-out resistances, and the other part, connected to the first by a lever, for dissipating the arc by distributing the self-induction sparks through five small contacts in series. In connection with the controller cylinder means may be provided for causing the motor, or motors, rapidly to attain a given speed and then to run uniformly at that speed. The contacts 1<A>, 2<A>, 3<A>, 4<A>, 5<A>, 6<A>, 7A, 8A, and 9 are mounted on the controller cylinder, and the contacts 1-9 are used in connection with the trolley T, motor field coils F, F<1>, F<2>, F<3>, resistances R<1>, R<2>, R<3>, R', R<5>, an auxiliary motor K, and a relay Q. The successive positions of the contacts are shown at A', B<1>, C', D<1>. At A', the motor is started with the field coil F short-circuited, and all resistances in circuit. The current operates the motor K, thereby moving the lever H over the rack G, but not moving the latter, and also operates the relay Q, whereby the latter is shortcircuited through the lever N and contact 0. This allows the spring L to pull the lever H over one tooth of the rack G. The counter electromotive force developed in the armature of the motor M reduces the current, and the relay magnet is weakened and allows the spring P to pull the lever N away from the magnet. This results in the energizing of the motor K, and causes the lever H to move the rack forward one tooth, thus cutting-out the resistance R'. The same series of operations is repeated to cut-out each resistance in turn, until the position B' is reached. By this time, the speed has attained the desired maximum, and the rack G having no more teeth, the motor K, relay Q, and their connections have no further effect. On turning the cylinder to the position C<1>, the coil F is no longer short-circuited, and the acceleration is arrested, the motor continuing to run at a uniform speed. The same principle is shown applied to an arrangement with less resistances and more ampÞre-turns of the field, and also two or more motors. An electric device for locking the controller cylinder against movement, until the current is shut off by an auxiliary switch, is formed by a solenoid the core of which holds, as long as the current passes, an arm in such a position that a pin is retained within a notch in a wheel mounted on the controller shaft. In a modification, the motors, such as those of trolley cars and elevated cars, are controlled by a variable counter electromotive force generated for the purpose. In another arrangement, a train of cars is shown, each having its own controller and motors, but connected together so that they may operate independently when the cars are detached, or be simultaneously operated from any desired point on any car of the train.