ULTRA-MINIATURE DIGITAL REMOTE MEASUREMENT SYSTEM FOR HARSH ENVIRONMENTS

Abstract

For the last dozen years, ELECTRICITE DE FRANCE has been using a digital telematry system mountable on the rotors of its generating machines in case of acceptance tests or after technical hitch, under difficult environmental conditions (125 degrees C and centrifugal acceleration of 100,000 m/s ). This system, manufactured by 2 SCHLUMBERGER, has proved itself in many test programs on high-power electrical motors, primary pumps of PWR reactors, steam turbines, alternators, etc. Today, the need is growing towards operational monitoring of equipment. Using this type of equipment in a monitoring system is a greater challenge. In fact, it is necessary to obtain an MTBF longer than the fuel refilling period (approximately 18 months) to make significant savings in product costs. A technological upgrade of the existing product was undertaken in late 1989. A very effective product capable of meeting the needs expressed is now available on the market. The system can be used to build systems with 1 to 63 channels with pass-bands ranging from 250 Hz to 10 kHz and very high precision (approximately 0.1%), under the above-mentioned environmental conditions. Its size, low power consumption, range of operating temperatures (-20 to 125 degrees C), resolution (12 bits), adaptability and capability of operating under conditions of acceleration and vibrations (100,000 M/s and 1000 m/s from 20 to 1000 Hz), make it a 2 2 unique product of its type. Although designed for use on rotating machines, these devices, thanks to the designs and technologies used, are compatible with other types of applications. The central equipment is also modular, a change in the structure of the rotor-mounted system does not call any of the investments into question; only the equipment’s software configuration is modified. A full line of standard equipment for reception, decommutation, recording and processing is available. This paper is intended to show how this product was developed so as to meet the main constraints of a system mounted on rotating machines. Problems related to installation on the machine, the power supply to the system and data transmission are not dealt with here. A short video film will illustrate our analysis.