GB234335A - Improvements in loading coil cases - Google Patents

Abstract

234,335. Western Electric Co., Ltd., (Western Electric Co., Inc.). Sept. 3, 1924. Addition to 153,995. Inductances.-A loading unit for a telephone system comprises a casing divided into magnetic shielded compartments containing separate groups of coils and their connections. The invention is particularly applicable to four-line repeater circuits employing separate lines for transmitting signals in opposite directions; any coupling between the loading coils of the two lines gives rise to excessive cross-talk. The apparatus shown comprises a casing 3 divided by partitions 6, 7 into compartments in each of which is mounted a spindle 4 on which loading coils are assembled. The shaded parts of the partitions 7 are extended above the others so as to divide the whole case into two main compartments 11, 12, each containing loading coils of lines transmitting in one direction only forming groups A, B respectively. In some cases loading coils of group A may be mounted in the lower part of the central space 13 and the corresponding coils of group B in the upper part. the two sets being separeated by an earthed washer. The cable stub comprising a shielded group of wires 15 surrounded by a group 14 enters the casing at the top of the compartment 11. The wires 14 are connected to the appropriate coils of group A and the wires 15 shielded by metallic tape 16 are led into the compartment 12 through a hole 8 in the partition, and connected to group B. The leads 17 to the group A coils in compartment 13 are led through insulated bushings 19 placed in a slot in the partition and are run down on the side opposite to that on which the B group connections are run.