GB500714A - Improvements relating to electrical transmission systems - Google Patents

Abstract

500,714. Electric signalling systems. SPERRY GYROSCOPE CO., Ltd., HARDING, W. C., and NISBET, R. H. May 7, 1937, No. 36627/38. Divided out of 498,738. [Class 40 (i)] Signals from a transmitter of the step-bystep type or of the selsyn " type are used to excite the windings of a constantly running generator so that receivers can be supplied with currents for positioning them. In Fig. 1, the generators 62, 63 and 64 are driven by a motor 65, and their field windings 67, 68 and 69 are energized by a step-by-step transmitter 70. Each segment 71, 72, 73 of the transmitter is connected to the negative terminal of the D.C. supply through a field winding and the contact brushes 74 and 75 are connected to the positive terminal. The field windings are energized singly or in pairs as the contact brushes rotate. The negative brushes of the generators are all connected to a line 76 so that four lines 76 to 79 are necessary. A three-line system using three generators is also described. In Fig. 3, a single generator 86 is used, the transmitter being similar to that in Fig. 1. The transmitter segments 71<1>, 721 and 731 are connected to equidistant tapping points on the stator winding. The rotor has a commutator connected to a closed winding and three brushes 80, 81, 82 spaced 120‹ apart rest on the commutator so that the voltages between the pairs of brushes are proportional to the excitation currents in the windings 67<1>, 68<1> and 69<1> of the stator. The brushes 80, 81 and 82 are connected through compensating windings 83, 84 and 85 on the stator to the lines 77<1>, 78<1> and 791 respectively. These compensating coils prevent distortion of the exciting field by the currents withdrawn from the rotor. Specification 433,494, [Group XX], is referred to in the Provisional Specification.