GB589584A - Improvements relating to electric telemetering systems - Google Patents

Abstract

589,584. Resistance measurements. BRITISH THOMSON-HOUSTON CO., Ltd. March 21, 1945, No. 7137. Convention date, March 22, 1944. [Class 37] [Also in Group XXXVIII] A direct-current telemetering device consists of a resistance of high temperature coefficient, which may be at a remote point, connected into the field circuit of an electromagnet so as to control the strength of the field produced by it and hence the position of a permanent magnet, situated in the field, and its associated pointer. In the Figure, the annular magnetic circuit 10 of highly permeable material, with air-gap 16, is magnetized by opposing coils 11 and 12 connected to battery 21. Cylindrical magnet 13, of high coercive force magnetic material, magnetized along a diameter, is rotatably mounted in its cylindrical axis coaxially with the annulus 10, and a damping ring 25, of conducting material, is interposed between it and the magnet 10. Coils 11 and 12 are both divided into two mutually opposing parts 11a, 11b and 12a, 12b respectively. 11a and 12a are connected across battery 21 in series with resistor 17 and 11b and 12b are similarly connected in series with resistors 22 and 23. The values of the latter resistors are so selected that with the temperature of resistor 17 at the lower end of the scale to be measured, the coils 12a and 12b balance magnetically, while at the higher end 11a and 11b balance, and the temperature range measurable is determined by the choice of values of 22 and 23. The device may be used to measure changes in the value of resistor 17 produced by mechanical means. In Fig. 2 (not shown), an alternative method of connecting coils 11 and 12 is indicated. Specification 552,168 is referred to.