Patent GB-633577-A (GB)
Title: Improvements in automatic control systems for electric locomotives
IPC: B60L15/00
Filed: 1947-08-27
Abstract: 633,577. Control of D.C. motors. FORGES ET ATELIERS DE CONSTRUCTIONS ELECTRIQUES DE JEUMONT. Aug. 27, 1947, No. 23654. Convention date, Feb. 25, 1942. [Class 38 (iii)] A control system for locomotive traction motors M<SP>1</SP>-M<SP>6</SP> comprises at least one master controller 5 and three auxiliary cam-shaft controllers 6, 7 and 8, which are reversiblv and intermittently driven by pilot motors 10, 11 and 12. The pilot motors are regulated to position the auxiliary controllers, by means of the master controller, through circuits comprising contacts on drums 6<SP>1</SP>, 7<SP>1</SP> and 8<SP>1</SP>. The controller 6 is adapted to control contactors in the main traction motor circuit which regulate the connection of the armatures of the traction motors in series, series-parallel, or in parallel. The controller 7 similarly adjusts the value of a series rheostat R in the main motor circuit, and the controller 8 regulates the value of the traction motor field excitation during both motoring and regenerative braking operation. The controller 6 is mechanically coupled to a reverser 9-9<SP>1</SP> which controls contactors in both the main traction motor circuit and the control circuits for positioning the members 6, 7 and 8. Movement of the handle C of the master controller is adapted to energize the pilot motors 10 and 11 and move the controllers 6 and 7 forwardly. The traction motor armatures are connected in series and then the armature resistance is reduced. Further operation is afforded by connecting the traction motor armatures in series-parallel and again reducing, the resistance in circuit. The transition from one grouping of the traction motor armatures to another may be effected by the " bridge " method. The rate of advance of the controller 7 may be controlled by means of an acceleration relay the sensitivity of which is regulated by means of a handle Eff on the main controller, or through contacts on the controller 8. In the event of wheel-slip the acceleration relay may be rendered ineffective to provide further movement of the controller 7. Other precautions in the event of wheelslip may be afforded. When the master controller is positioned to provide reduced field excitation for the traction motors, a portion of the series armature resistance is first re-inserted, this resistance afterwards being removed. This operation is afforded by appropriate movement of the controllers 7 and 8. It is possible to effect a new grouping of the armatures of the traction motors without varying the field excitation, the controller 8 being stationary during such operation. When the master controller is actuated to provide gradual return from a position providing a high-speed grouping of the traction motor armatures with reduced-field excitation to one affording a low-speed grouping with fullfield excitation, the controller 8 is first moved to its full-field position, and then the controllers 6 and 7 are reversed, the controller 6 being moved only when full armature resistance obtains. When the return to a position of the master controller providing a lower-speed grouping of the traction motor armatures with reduced-field excitation is desired, contacts on the drum 7<SP>1</SP> are used to provide step-bystep movement of the controller 8. Gradual return of the auxiliary controllers to their "off" positions is provided by positioning the master controller at the first notch affording series-connection of the traction motor armatures, and then moving the arm C to the " off position. Quick-return is afforded by moving the arm C directly to the neutral position, During such quick return a main contactor 3 is maintained closed by means of a time-delay relay which is intermittently energized through contacts on the drums 61 and 71. Jamming of one of the controllers in an intermediate position leads to opening of the main contactor. For regenerative braking operation the handle C is moved to the notches Rec providing connection of the traction motor armatures in series, series-parallel, or parallel. The controller 8 operates to connect the traction motor field windings in series with an exciter E, the controller 6 is positioned to connect the armatures in the desired grouping, and the controller 8 remains stationary. The excitation of the machine E is regulated by means of the handle Eff and, when the traction motor voltage equals that of the supply, the coritactor 3 is closed and the controller 7 is moved to reduce the resistance R.