Patent GB-190326273-A (GB)
Title: Improvements in Controlling Devices for Electric Motors.
Inventor: KOHLER GUSTAVUS ADOLPHUS EDWAR
Filed: 1903-12-01
Granted: 1904-03-24
Abstract: 26,273. Kohler, G. A. E. Dec. 1. Driving machines by electromotors.- Relates to the control from a distance of the motor for operating printing- presses &c. Push-buttons are provided, and control the circuits of relays or solenoids, which in turn control the resistance switch, reversing- switch, &c. One push-button serves to start the motor, the resistances being automatically cut out, a second stops it slowly, a third reverses, and the fourth serves to stop the motor suddenly in cases of emergency. Fig. 1 is a diagram of the circuits, and Fig. 3 shows the construction of a switch for cutting in or out resistances and performing other functions. The core B<1> of the solenoid B carries contacts B<2> rubbing over the resistance contacts B<3>. Normally the core is held up with the contacts B<2> on dead contacts B<6> by a catch controlled by a magnet E. The core is also fitted with a rod B<7> carrying contacts F<1> adapted to engage contacts F<4>, F<5>, F<6>, F<7>, F<8> according to its position. In the diagram, the power circuits are shown in heavy lines and the control circuits in fine lines. A push-button 1 (or any one of several such pushbuttons, at different places) serves to start the motor G<0>. On closing it, a circuit is closed through the electromagnet E, causing it to release the core B<1>, which slowly drops, being fitted with a dash-pot arrangement, as shown in Fig. 3, and cuts out resistance. At the first movement of the core B<1> the circuit of the solenoid A is closed at the contacts F<6>, F<7>, and the armature circuit of the motor is closed by the switch A<1> carried by its core. To stop the motor slowly, the pushbutton 2 is operated. This closes the circuit of the solenoid D, which closes the circuit of the solenoid B, and its core is slowly raised, introducing the resistances. Finally, the circuit of the solenoid A is opened, and the armature circuit opened at A'. To reverse the motor, the push 4 is closed. This closes a circuit through the solenoid D, closing the switch D' and completing a circuit through the coil B, lifting its core and making contact at F<5>, F<8>. This closes the circuit of a solenoid C, operating a switch C<1> and completing the armature circuit in the reverse direction. The motor continues running only so long as the switch 4 is closed. To stop the motor suddenly, the push 3 is operated. This breaks the circuit at K, and opens the circuit of the solenoid A, allowing the switch A' to open and A<2> to close. This short-circuits the armature, and stops the motor. In a modified arrangement, the core B<1> of the solenoid B, instead of having a switch at its upper end, carries an additional contact-piece H, Fig. 9, at its lower end, adapted to engage additional contacts H', H<3>, H<5>, H<6>, &c. having somewhat similar functions. The cores of the solenoids A, C carry sets of switches which control the motor circuits. The emergency switches 3 and connections are also somewhat differently arranged and the electromagnet E is fitted with auxiliary contacts E<4>, E<5> which are closed when the magnet is energized. In this arrangement the same set of contacts and resistances is used for both backward and forward running.