Patent GB-190405213-A (GB)
Title: Improvements in and relating to Controlling Electric Motors.
Inventor: GEIPEL WILLIAM
Filed: 1904-03-02
Granted: 1905-04-01
Abstract: 5213. Geipel, W., Lange, F. M. T., and Mascord, G. W. March 2. Driving machines by electromotors.-Relates to controlling shunt-wound motors such as are used with printing machines &c. where the motors are required to run at various speeds, and consists of improvements in the method described in Specification No. 14,509, A.D. 1891, [Abridgment Class Dynamo - electric generators &c.]. The main motor C is driven by an intermediate generator B, adapted to produce a maximum voltage of half that required by the motor C when running at full speed, the generator B being driven by a motor A connected through the leads a, b to a source of power of constant voltage. When the speed of the main motor has attained the value corresponding to the maximum voltage of the generator B, which is half that of the voltage of the mains a, b, the armatures n, t are automatically connected in series across the mains a, b, the armature n acting to oppose the flow of current in the armature t, and the speed of the motor being then gradually increased to its maximum by inserting resistance in the fields of the generator B and motor C. The method of operation is as follows:-The motor A is started by operating the starting - switch D, which may be of any suitable form, and the handle N<3> of the switch N is moved to the left, when, the solenoid L becoming energized, the rod O (connected to which is a dash-pot O<1>) moves to the left, the brushes 10, 13 gradually cutting out the resistance 8* ..., 9* ... in series with the field m of the generator B, the speed of the motor C being thus gradually increased. The motion of the rod O may be regulated by the device described in Specification No. 5214, A.D. 1904, [Abridgment Class Dynamo-electric generators &c.]. When the rod O has moved into the position in which the brush 10 bridges the contacts 8<6>, 9<6>, the brush 22 of the change-over switch K connects the contacts 19, 21, thereby completing a circuit through the solenoid 24. A rod 25 carrying brushes 27, 31 and 26 is drawn down, and the armatures n, t thus connected in opposition across the mains a, b ; at the same time the circuit of the solenoid 24 is broken, and that of the solenoid 23 so connected up as to be completed when the brush 22 spans the contacts 19, 20. Further movement of the rod 0 to the left introduces resistance into the field circuit of the generator B, thereby decreasing the voltage across the armature n, with consequent increase of the voltage across the armature t, while at the same time the insertion of resistance 11* ..., 12* ... into the circuit of the field s also increases the speed of the main motor C. By moving the handle N<3> to the right, the various operations above described take place in the reverse order, while the speed of the motor C may be maintained constant at any definite value by placing the handle N<3> midway between the contacts 1, 2 when the motor has attained the required speed. The Provisional Specification also states that the voltage of the generator B may be diminished by reducing its speed.