发明名称 Improvements relating to the dynamo-electric braking of electrically propelled railway vehicles
摘要 751,925. Control of D.C. motors. KINGS MILL, H. L. Aug. 24, 1954 [Sept. 11, 1953]. No. 24570/54. Drawings to Specification. Class 38(3) Relates to a system of combined regenerative and rheostatic braking for traction motors with series-parallel control, the range of speed and braking-effort obtained during series regeneration being extended to include the range normally covered by parallel regeneration by the inclusion of substantially the whole of the starting resistance in series with the motor armatures. After the motors have been initially' connected in series for regenerative operation, the field strength is automatically increased and then the series resistance is gradually removed as the speed is decreased, whereupon a transition to rheostatic braking is effected, the fields of the motors being deenergied before rheostatic braking connections are established and re-energized as soon as these connections have been made. Maximum field strength is maintained during removal of the rheostatic braking resistance, which is controlled by sequentially-actuated contactors, until only one section of resistance remains in circuit with each motor for a period whereupon this section is removed and the fields of the motors are weakened. When the motors are initially arranged for regeneration and the voltage' developed by the motors does not reach a sufficient value in a given time interval. the line connections are not completed and the rheostatic braking circuits are established. The time interval referred to may be measured bv the rate of growth of field current acting on a relay. An over-voltage relay interrupts the field circuits of the motors and makes the rheostatic braking connections when there is an over voltage during regenerative operation. The speeds of the motors are regulated during braking operation by means of a current limit relay which controls the rate of increase of field strength and removal of series resistance, and this relay may have a bias coil which is excited in different directions' and in different degrees according to the position of a brake controller whereby the permissible braking current is altered on different notches of the controller. Alternatively, the contacts of the current limit relay may be supplied from a contact on the brake controller which can be opened when it is desired to reduce the rate of deceleration. A constant voltage exciter may be provided for the motor field windings, the field strength being varied by means of a series resistance controlled by sequentially-actuated contactors.
申请公布号 GB751925(A) 申请公布日期 1956.07.04
申请号 GB19540024570 申请日期 1954.08.24
申请人 HENRY LLEWELYN KINGSMILL 发明人
分类号 B60L7/12;B60L7/22 主分类号 B60L7/12
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