Patent GB-402072-A (GB)
Title: Improvements in or relating to electric control means for internal combustion engine-electric generator power units
IPC: H02P9/00
Filed: 1932-04-04
Abstract: 402,072. Electromagnetic interrupters; motor control systems. WESTINGHOUSE ELECTRIC & MANUFACTURING CO., East Pittsburg, U.S.A.-(Assignees of Freeman, N. L.; 598, East End Avenue, and Storer, N. W.; 6818, Reynolds Avenue, both in Pittsburg, U.S.A.) April 4, 1932, No. 9629. Convention date, April 2, 1931. [Classes 38 (iii) and 38 (v).] A power unit consisting of an internal-combustion engine E and an electric generator G has a throttle mechanism T giving a number of speeds, each appropriate to a given position thereof, and regulating means for the excitation of the generator adapted to control the generator output to maintain constant speed, this means being adjusted in accordance with the throttle setting to respond differently at each setting whereby a different speed is maintained constant. The system comprises an auxiliary generator driven by the engine for excitation for regulation and for auxiliary purposes, and a source of constant potential such as a storage battery B whereby the auxiliary generator is excited to give a voltage proportional to o engine speed, and whereby the power unit may be started. The regulator comprises a relay V connected across the armature of the auxiliary generator to control the resistance in series with the field 35 of the generator G, and a dynamic control relay R V, also responsive to the voltage of the auxiliary generator A, causing vibration of the relay V. In the system described, when switches 3, 4 are closed the main generator operates as a starting motor with a series field 31 assisting the shunt field 35, and it charges the battery so long as idling speed is maintained ; the rate of charge may be adjusted by a switch 38 controlling resistance in series with the field 35, the field 31 preventing excessive charging. After starting, when the engine speed is raised above idling speed the dynamic control relay RV opens its contacts 16 causing contactors 14, 26 to open and disconnect the battery B from the generator G. The dynamic control relay RV is actuated against a spring 210 by a stationary coil 68 and a movable coil 67 in series connection. The movable coil is disposed in the air gap between a stationary armature 207 and a movable armature 208 so that a substantially uniform field is produced over the entire air gap and the range of movement of the coil 67. The figure shows its position when not energized. After opening its contacts 17 as the voltage of the auxiliary generator rises due to increasing speed of the power unit the relay next opens contact between 61 and 42 to remove the short circuit on a resistance 441 which prevents hunting, then vibrates upon contact 107 at the rate of 7 to 10 times per second to effect output regulation of the generator G. Under high speed conditions of the power unit it vibrates the contact 61 against the lower fixed contact at a rate gradually diminishing from about 100 times per second to cause intermittent to permanent shunting of the field 58 by the resistance 44 to prevent further rise of the auxiliary generator voltage. The system comprises traction motors which remain connected to the generator G throughout the running positions of the throttle controller TC the connections being effected by the automatic reverser on actuation of the reversing controller R from the idling position to its forward or reverse position after starting the engine by means of the push-button 9 or starting controller 8. Transition from series to parallel connection may take place in any position of the throttle controller by actuating the independently operable selector controller S and to avoid subjecting the motors to full generator voltage immediately, the regulator contactor V is de-energized the instant transition is to take place and the generator field reduced in consequence ; when the change is complete normal conditions are re-established. The selector controller is also adapted to increase the speed of the motors by shunting their series fields.