Ferranti Plc

Ferranti International Plc

John D Davidson

Donald A Campbell

Alexander G Gillies

Peter G Moore

An assembly is provided including two members capable of relative rotation about a common axis, and with electrical interconnections extending between the two members, the assembly, being for example, part of a gimbal system, wherein the electrical interconnections may be divided into two groups, selected such that, because of the voltages, and/or currents, carried by the electrical interconnections, it is desired that the electrical interconnections of one group are screened electrically from the electrical interconnections of the other group, by a screen which does not extend along the whole length of either group. An annulus-defining, rotatable, member is provided which is closed at one end, between radially inner and outer, constituent member sections, and a second, fixed, hollow, cylindrical member divides the annulus into radially inner and outer constituent sections, wherein a tape, comprising one group of electrical interconnections, extends between the intermediate member and the outer member section; and another tape, comprising the other group of electrical interconnections, extends between the intermediate member and the inner member section; the two tapes being loosely coiled, in the same direction, in the associated inner and outer annular sections, the assembly being so constructed and arranged that the tapes are screened electrically from each other by the intermediate member.

Assembly including two members capable of relative rotation and with

A servo system 10 (FIG. 1) for positioning a sighting mirror 11 connected to a pulley 16 comprises a drive motor 13 rigidly connected to a drive pulley 15 in turn coupled by a tensioned drive belt to the pulley 16. Angular position of the motor or pulley 15 is measured by sensor 18 and passed by way of phase advance network 19 and amplifier 21 to produce an error signal for the drive motor. The pulley 16 is outside of the servo loop and any oscillations induced in the tensioned belt at its resonant frequency, possibly originating from electrical noise in the servo loop, will be uncontrollable. To avoid such oscillation and retain a simple construction the belt tension is set (25) to a value producing a belt resonant frequency outside the operating bandwidth of the servo system and the feedback loop includes a notch filter 20 tuned to the belt resonant frequency which prevents electrical noise in the system from inducing along-axis oscillation of the drive belt and consequential position jittering of the mirror sightline.

Growing community of inventors

Lothian, United Kingdom

John D Davidson