GB1182855A - Improvements in or relating to the Reduction of Wheel Slip in Locomotives. - Google Patents

Abstract

1,182,855. Control of motors. HAWKER SIDDELEY DYNAMICS Ltd. 27 Jan., 1969 [26 Jan., 1968], No. 4287/68. Heading H2J. In a system for reducing wheel slip in railway locomotives in which the energizing voltage is temporarily removed (from all motors) when slip is detected the rapid build-up of current consequent upon restoration of the voltage is checked at a value less than that which obtained when slip was detected, further increase occuring only at a slower rate. The object is to prevent the immediate recurrance of slip. The current in each motor M (there may be six), is detected by a magnetic dependent resistor 11 in a C-core 12 surrounding each bus-bar 14. The current signals are differentiated at 19 to provide rate of change signals which are combined and amplified at 20. If the rate of change exceeds a threshold value in a device 21 this is deemed to be due to wheel slip and an over-ride signal is applied to the regulator 17 of a diesel driven generator 15 to reduce its output to zero. The rate signal is also applied to a memory circuit 22 which comprises an integrating capacitor, the charge on which represents motor current, and when slip occurs this discharges at a predetermined rate. When slip has ceased the voltage is restored and the current rapidly increases to a value corresponding to the now reduced charge on the capacitor, and further increase occurs at a rate determined by the charging rate of the capacitor. The slip signal may also be applied to an engine regulator 18 to prevent undesired governor reset and the system may be combined with one in which motor currents are compared and a small reduction of current is made if this indicates " creep " or slip at high speed, but this arrangement is not described in detail.