Patent GB-190721551-A (GB)
Title: Improvements in Control Systems for Electrically Propelled Vehicles
Inventor: COOPER WILLIAM
Filed: 1907-09-28
Granted: 1908-06-25
Abstract: 21,551. Cooper" W. Oct. 3, 1906, [date applied for under Patents Act, 1901]. Motor control systems. - Motors driving independent wheels of a vehicle are both cut out of circuit when their speeds differ, for example owing to slipping. The cut-out device consists of a differentially wound relay 44, of which each coil 46, 53 is placed across the terminals of one armature 1, 4, so that, when one motor speeds up due to a slip of the wheel, its back electromotive force increases and lessens the current through the corresponding relay coil. This raises a bridge 33 and breaks the switch-actuating circuits, all of which are threaded through the contacts 31, 32. The position a in the controller closes a switch 28 from a contact 23, and switches 12, 15, 17, 18 from a contact 24 through branching conductors 30. An additional switch 42 is closed from a contact 26 through a conductor 37 and fingers 40, 41, which are bridged, in the 'off' position of another switch 39. A wire 29 and its branches act as a common return for all the actuating circuits. The motors are thus connected in series between a shoe 9 and a return conductor 51, and in circuit with a throttle 43, resistances 47, 48, the switch 42, and resistances 49, 50. An accelerating circuit leaving the wire 27 passes through the throttle contacts to switch contacts 56, 58, and thence through the bridged contacts 60, 61 of the switch 42 to a switch 67, which controls the first step of resistance. The action of each resistance switch 67, 72, 77, 78 consists in first supplying its own actuating coil through contacts such as 66, and then as the switch operates, cutting out the circuit through the throttle and replacing it by current direct from the contact stud 23. This current is led by a branch of the wire 27 to a live stud 75 on a resistance short-circuiting switch 39 and bridged through a wire 27<1> to studs such as 73 in each resistance switch. The making of these actuating and maintaining circuits is continued automatically, the former being transmitted from switch to switch by wires a<1>, and the latter by wires b<1>. As soon as all the resistance has been cut out by the operation of all the switches up to switch 78, a conductor 79, taking up the actuating current of the switch 78, carries it through the switch 39 and a paralleling switch 85, both switches being off, to the coil of the switch 39, which closes and cuts out all the resistances leaving the motors in series, independently of the switch 42. The circuit of the latter is simultaneously broken at the studs 40, 41, and the circuit of the resistance switches is broken at the studs 74, 75. The operation of the switch 39 by bridging contacts 88, 89 energizes switches 91, 85, which put the motors in parallel with resistance, in series, this position being completed by the de-energizing of the switch 39 owing to the break in its circuit at the studs 83, 84. In this position, the resistance switches are operated as before, but from studs 92, 93, 94 of the switch 85. The position x of the controller operates switches 13,14,16,19, which reverses the direction of current in the armature. In positions b, y, the progressive accelerating action of the resistance switches''is stopped, the switches already energized being maintained closed by currents from the contacts 23.