Patent GB-191507177-A (GB)
Title: Improvements in Switching-over Systems for Electrical Lighting Installations for Railway Trains and the like.
Inventor: GROB HUGO
IPC: H02J7/34
Filed: 1915-05-12
Abstract: 7177. Grob, H. May 12. Lighting and heating system s.-Relates to automatic switching arrangements in train - lighting systems having an intermittently-working generator. The invention consists of an arrangement whereby, with decreasing dynamo speed, automatic switching-apparatus for restoring the connexion of the generator, batteries, and lamps, to their condition at rest is operated by increasing exciting- current. The invention is shown applied to a train-lighting system wherein the dynamo A has two armature windings and two commutators, one supplying a higher and the other a lower voltage. The functions of the two commutators in exciting and regulating the dynamo are as described in Specifications 14,059/07 and 2719/11, [Class 35, Dynamo-electric, generators &c.]. The present invention is concerned with the manner in which switches F, F<1>, G, G<1> are automatically actuated to change the circuits as required. Each of the switches comprises two movable contact members coupled together, and the normal position of the contact members, when the dynamo is at rest, is such that the points 20, 21 are respectively connected to the points 13, 15 and the points 22, 23 respectively to the points 17, 19, all the four contact members lying on the right-hand side of the middle off-position shown. In this condition, the low-voltage commutator is connected to the dynamo exciting-coil B, the high-voltage commntator is disconnected, and two batteries C<1>, C<3> are connected in parallel to feed the lamps D. When the dynamo starts and attains a sufficient potential through self-excitation, an electro-magnet coil H' in a high-resistance connexion between points 11, 20 moves the switches F, F<1> over to the left-hand side, thereby putting the battery C<1> on charge and connecting the full dynamo voltage in parallel with the battery C<2> to feed the lamps. As a result of the change, current is supplied to an electro-magnet winding H' in the charging-circuit, and the switch is held on firmly in its new position as long as the current flows in the proper direction. The dynamo voltage, continuing to rise relatively to that of the battery C<2>, after a time reverses current through an electro-magnet winding H', which moves the switches G, G<1> over to the left-band side and thereby connects the exciting coil B to the battery 0<2> and puts the lamps on to high-voltage commutator of the dynamo. A switch E acting later when the dynamo voltage rises to the limit, breaks the self - exciting connexion, and reduces the dynamo voltage to a small amount below that of the battery C<2>. The winding H<4> now carries the whole of the exciting-current, which depends on the amount by which the dynamo voltage is below that of the battery C', and diminishes as the dynamo speed increases. When, afterwards, the dynamo speed decreases, the current in the coil H<4> increases and, at a value determined by the adjustment of the switching -apparatus, returns the switches G, G<1> to the position occupied during rest. Specification 24,537/14 also is referred to.