Patent GB-1160559-A (GB)
Title: Telemetering Systems
Inventor: WARDLE LEONARD GEORGE
IPC: G01K1/02
Filed: 1965-09-24
Abstract: 1,160,559. Measuring electrically. ENGLISH ELECTRIC CO. Ltd. Sept. 23, 1966 [Sept. 24, 1965], No.40754/65. Heading G1N. A device for monitoring a parameter, e.g. the temperature, of a rotating member, e.g. the windings of the rotor of a current generator, at selected positions throughout the member comprises sensitive elements, e.g. resistors or thermocouples, located at the selected positions, each associated with an R. F. generator and aerial, to generate separate output signals modulated in accordance with the magnitude of the parameter, and a stationary signal receiving aerial mounted adjacent the member for successively receiving the modulated output signals from the transmitting aerials, spaced circumferentially of the member, as the member is rotated. In the embodiment, thirty two platinum resistance gauges 6, (not all shown), Figs. 1, 3 (former not shown), are arranged throughout the rotor (5), each forming part of a D.C. bridge circuit whose output is connected to an oscillator 44, see also Fig. 4 (not shown), so that the output signal of the oscillator, generated in the inductive aerial 10, is frequency modulated. Each bridge is energized from a power pack 43 including a rectifier bridge and smoothing network, in turn energized through transformer 50, aerials 42, 41, (or slip rings), from a power supply 40. In a modification, an A.C. bridge network may be used, the power pack being omitted. The signal transmitting aerials 10-25 and 110-125, Fig. 2, are arranged in two annular tracks round a hub secured to the rotor, each track being associated with a receiving aerial 30, 130, which is connected via an amplifier 45 to a temperature register 46 in which the sensing signals are printed out or visually displayed. If desired the equipment may be arranged to give a control and/or alarm signal when one or more of the temperatures monitored exceeds a pre-set magnitude. Also provided on the tracks, alternating with the signal transmitting aerials, are pairs of linked counter aerials 10A-25A and a pair of linked marker aerials 26. These aerials, together with stationary counter aerials 31, 131 and marker aerials 27 provide means by which the sensed signals can be identified. In operation, one of each pair of aerials 31, 131, 27 continuously emits R.F. signals, the other of the pairs of aerials thus receives a signal only when a pair of linked rotating aerials are in correspondence with the pair of stationary aerials. Thus for each rotation of the rotor a marker signal is generated, which is fed to a marker register 47, and 32 counter signals are received and fed to the register 47 alternately from each track, each time the signal receiving aerials 30, 130 are lined up with one signal transmitting aerial in each track. The register 47 is arranged to operate on the temperature register 46 to provide identification of the sensed signals received. The frequency of the counter and marker signals is arranged to be different from that of the sensed signals in order to prevent interference between them. In a modification the aerials 10-25, 110, 125, 30, 130 may be made of conductive plates, e.g. of copper, transmission being through capacitative rather than inductive coupling. The counter aerials may then be omitted, counter signals being derived from stationary aerials which inductively sense the areas of conductive material. The marker aerial may then be formed of a dummy capacitative aerial, detected by a marker aerial similar to the counter aerials.