GB640521A - Improvements in cooler systems for generator electric locomotives - Google Patents

Abstract

640,521. Automatic, temperature control systems. GENERAL MOTORS CORPORA.- TION. July 18, 1947, No. 19250. Convention date, Oct. 5, 1945. [Class.38 (iv)] A cooler system for a generator electric locomotive having an engine with radiators through which an engine coolant is circulated, comprises an engine-driven alternator interconnected with a plurality of induction motors adapted to drive fans for the respective radiators. A sequential start-up of the fan motors as the coolant temperature rises above a predetermined minimum, and a simultaneous shut-down of the fan motors as the coolant temperature falls below the minimum is caused by relaycontrolled switches under the control of a coolant-temperature responsive device. The electric locomotive comprises a power-generating unit including an internal-combustion engine 5 (Fig. 1) connected to a traction generator 7 in turn connected to a three-phase alternator 9 for supplying power at frequencies proportional to the engine speed to four induction motors Ml-M4 driving cooling fans 29. The motors draw air through shutter vanes 37 (Fig. 2), and engine cooling radiators 25, and expel the air through air exhaust stacks 27 in the roof of the locomotive. The shutter vanes are controlled by an electric pneumatic shutter valve 43 (Fig. 4) included in a control circuit together with a temperature switch 77 responsive to the temperature of the water circulating in the radiators and which includes a thermally-expansible element 95 secured at one end to a stationary member 96 and at the other end to a stepped contact 97 adapted to engage successively fixed contacts 101, 103, 105, 106, 107 and 108. If the temperature of the cooling water reaches a given value slightly below the minimum value for which cooling is applied, the bar 97 engages the contact 101, thus setting up a holding circuit for the winding of a current relay 81. If the temperature of the cooling water further increases to the minimum value, the bar 97 engages the contact 103, thus energizing the relay 81 which in turn completes a circuit through the windings of two sequence relays, 83, 85, and energizes the valve 43 causing the shutters 37 to open. A holding circuit is also made ready for the motor contactors 87, 89, 91 and 93. Further increases in temperature cause contacts 105-108 to be engaged successively by the bar 97, causing successive energization of fan motors M4, M2, M3 and M1, respectively. Due to the holding circuits of the various relays all the motors continue to operate until the temperature of the cooling water falls below the minimum when the relay 81 is released, causing the motors to shut down simultaneously. The sequence relays 83, 85 are adapted on release to be rocked so that the next time the temperature rises the fan motors are operated in the reverse sequence to ensure even wear.