Patent GB-399890-A (GB)
Title: Improvements in and relating to automatic switch gear employed in connection with electrical installations of railway vehicles or the like
IPC: H02J7/14
Filed: 1932-04-20
Abstract: 399,890. Variable-speed generator systems. KARIM, F., Railway Road, Lahore, Punjab, India. April 20, 1932, No. 11343. [Class 38 (iv).]. Relates to a fine wire double battery train lighting &c. system and consists in using a single switch mechanism to perform the functions of the auto-cut in and out switch, battery change-over switch and embarkation lighting switch previously used. Electromagnets 58, 58a, Fig. 6, have shunt and series windings connected in the generator circuit and suspended between them an armature 55 having coils 56, 56a wound in opposite directions. These coils are energized alternately from the generator by contacts mounted on a sliding frame 74 which is reset by each movement of the armature. When the armature is in the centre, brushes 61, 61a engage a contact 63 to which is connected the load and place the batteries connected to 62, 62a in parallel across the load. The paralleling main 69a is connected to the load by a sliding contact 80 and the embarkation lighting circuit 66, 66a is completed by brushes 65, 65a engaging a bridgepiece 67. When the generator voltage is sufficient the armature will move either to the right or to the left according to the position of the sliding frame 74. In the position shown it will move to the left. In that position contact 61 is moved into engagement with generator contact 79 thus connecting the battery to the generator, but leaving the other battery connected to the load. Sliding contact 80 connects the paralleling main to the generator and the embarkation lighting circuit is broken by brush 65 being moved out of contact with contact 67. When the generator fails the current in the shunt winding reverses and the armature is repelled. This gives positive action and avoids sticking. In a modification, Fig. 9, the switching mechanism is operated by a solenoid having a plunger 86 which in its lowest position is supported by a pivoted guide 104, Fig. 11, which can be moved into two positions. In the raised position of the plunger a pin 107 on the link 102 engages a spring lever 109 and rocks it about a pivot 112. With the guide in the position shown the lever will be rocked anticlockwise and it resets the guide so that on a fresh energization the lever will be moved clockwise. Mounted on the spindle of lever 109 are two levers 114, 115, Fig. 9, connected by spring links 116, 117 to levers carrying contacts 45, 47, Fig. 10. Mounted between these levers is a lever carrying a contact 46 connected to the paralleling main. This lever has an arm 125 which engages the outer levers, so that when either is moved the centre contact is carried with it. When the plunger is in its lowest position the contacts 45, 46, 47 engage a bar contact 44, Fig. 9, connected to the load but when it is in its raised position one of the outer contacts and the middle are moved into engagement with a bar contact 43 connected to the generator. The embarkation lighting circuit is broken bv a roller 49 being moved out of engagement with a sprung contact 48 by means of a spring link 106 connected with a lever 126 on which the roller is mounted.