Patent GB-190400821-A (GB)
Title: Improvements in Systems of Electric Motor Control and in Controlling Apparatus therefor.
Filed: 1904-01-12
Granted: 1904-12-01
Abstract: 821. British Thomson-Houston Co., [General Electric Co.]. Jan. 12. Motors, controlling. -Relates to controllers of the type used in electric trains, being especially adapted for use with serieswound motors arranged in pairs. The field of each motor is divided into two parts, the intermediate points being electrically connected. The motors of each pair are in parallel, and each pair is provided with three terminals, one of which is connected to the mid points of the two fields each armature being always in circuit with at least half of its field. On operating the controller, the two groups of motors are first connected in series, the common armature terminal of one pair being connected to the source of current, and the other common armature terminal to ground, all the fields being in the central portion of the circuit, and finally in parallel without at any time opening the main circuit, the intermediate steps making various combinations of the half-fields and the remaining parts of the motors, thereby producing increasing speeds. When the controller is in the position indicated by the line 1, Fig. 5, the current passes from the trolley T through the electromagnetic blow-out F<2> and contacts 30, 32 to the cut-out switch E, which may be of any well-known form adapted for cutting-out any of the motors when they become disabled, thence through the armatures M<1>, M<3> to the contacts r, r<2> of a reversing- switch B, Fig. 1, through the fields K<1>, K<3>, contact r<1>, and cut-out E to fingers f<10>, f<9>, thence through the cut-out E, contact r<4>, fields K<2>, K<4>, and armatures M<2>, M<4> to the fingerf through the contacts 18, 19 to the finger f<7>, and thence through the resistance R to ground, the circuit being represented by 1, Fig. 6. In moving through the positions 2, 3, 4, Fig. 5, the resistance R is gradually cut-out ; in the position 5, the mid-field terminals h, h<1> come into play, when half the field of the first group of motors is connected in parallel with half the field of the second group ; in the position 6, Fig. 6, these two half-fields are shortcircuited ; while, when the position 7, Fig. 6, is reached, the armatures with half their fields are in parallel, half the fields of each group being in series ; and, finally, in the position 8, the two groups of motors are in full parallel. An electromagnetic blow-out F<5>, Fig. 5, is also described which may be used in combination with the controller or separately. It consists of a vertical bar h, Figs. 1 and 4, connected to the back of the controller case, and preferably insulated therefrom by a strip h<4>. Connected to the bar h are a number of horizontal bars h<1>, the ends of which are situated between adjacent fingers of the controlling-switch, the bars being excited by the main current passing through coils h<2> so wound as to produce alternate north and south poles. Any arc which is formed is deflected laterally, thereby preventing the formation of an arc between adjacent fingers. The pole-pieces are protected by insulating-septa h<3>, Figs. 1 and 3, carried by the bars which loosely fit into slots in the septa, and by springs s<1>, so that each septum may be separately removed.