Patent GB-240151-A (GB)
Title: Improvements relating to electric distant control systems
IPC: G08C19/38
Filed: 1925-09-10
Abstract: 240,151. Granat, E., and Compagnie des Forges et AciÚries de la Marine et d'HomÚcourt. Sept. 20, 1924, [Convention date]. Selective distant control systems.-The movement of the brushes upon the commutator of a motor supplied with polyphase alternating current is reproduced at a distance by a receiver motor. The movements of several controlling parts at the transmitter may be added algebraically at the receiver. As shown in Fig. 1, the transmitter A comprises a motor having its rotor supplied with polyphase current by fixed brushes 7, 8, 9 which rest on the commutator and are connected to polyphase mains L. Brushes 10, 11, 12 also resting on the commutator are adapted for displacement, through a gear wheel 33 and pinion 32, by a controlling handle 31. The field of the motor comprises a polyphase winding 1 supplied by the mains L. The brushes 10, 11, 12 are connected through slip rings to line wires 16, 17, 18 connected to the polyphase rotor 20 of a receiver motor B, the stator of which has a polyphase winding 19 supplied by the mains L. When the brushes 10, 11, 12 are stationary, the frequency of the currents in the wires 16, 17, 18 is the same as the frequency of the current supplying the mains L. The stator and rotor of the receiver are thus supplied by currents having the same frequency so that the revolving fields of the stator and rotor have the same speed and consequently no mechanical couple is produced at the receiver. When, however, the brushes 10, 11, 12 are rotatably displaced, the frequency of the receiver rotor currents is varied, and the rotor is rotated until the brushes 10, 11, 12 are again brought to rest. The receiver thus repeats the movements of the control handle 31. By employing several transmitters and receivers, the algebraic sum of the movements of the controls of the transmitter may be given at the receivers. For example, two transmitters of the type shown in Fig. 1 may be connected to the polyphase windings of the stator and rotor of the receiver and the total movement of the rotor gives the algebraic sum of the movement of the control handles. The rotor of the receiver may control the movable brushes of a third transmitter which is connected to the rotor of a second receiver. The stator of this receiver may be connected to the movable brushes of a fourth transmitter and the system may be extended in a similar manner so that the final receiver gives the sum, of the movement of any number of controlling handles. Fig. 4 shows a modification of a system for adding two movements wherein a single transmitter is employed. The transmitter A comprises an electric motor having a rotor E provided with two commutators 1, 2. The rotor and stator and a set of movable brushes 9, 10, 11 controlled by a handle V<1> are supplied by polyphase mains L. Brushes 15, 16, 17 adapted to be displaced by a handle V<2>, are connected by line wires 21, 22, 23 to the rotor 30 of a receiver B, the stator of which is supplied by polypliase current. Movement of either set of movable brushes varies the frequency of the current in the lines 21, 22, 23 and causes the rotation of the receiver. The movements of the handles V<1>, V<2> may therefore be added at the receiver. In a modification, the stator of the receiver may be connected to a transmitter of similar construction so that four movements may be added. In a further modification a number cf transmitters of the type shown in Fig. 4 are used in such a manner that the rotatable brushes of the commutator 2 of each transmitter are connected with the movable brushes of the commutator 1 of the succeeding transmitter, the final transmitter being connected to a receiver of the type shown in Fig. 4. Specification 232,571 is referred to. The Specification as open to inspection under Sect. 91 (3) (a) states that an electric generator may be used as a transmitter. This subject-matter does not appear in the Specification as accepted.