Motor Control Handbook A Guide For Electrical Contractors

Electrical temperature measurement The measurement of temperature is of special importance in numerous processes, with around 45% of all required measurement points associated with temperature. Applications include smelting, chemical reactions, food processing, energy measurement, and air conditioning. The applications mentioned are so very different, as are the service requirements imposed on the temperature sensors, their principle of operation, and their technical construction. In industrial processes, the measurement point is often a long way from the indication point; this may be demanded by the process conditions, with smelting and annealing furnaces, for example, or because central data acquisition is required. Often there is a requirement for further processing of the measurements in controllers or recorders. The direct-reading thermometers familiar to us all in our everyday life are unsuitable for these applications; devices are needed that convert temperature into another form, an electrical signal. Incidentally, these electrical transducers are still referred to as thermometers, although, strictly speaking, what is meant is the transducer, comprising the sensor element and its surrounding protection fitting. In industrial electrical temperature measurement, pyrometers, resistance thermometers, and thermocouples are in common use. There are other measurement systems, such as oscillating quartz sensors and fiber-optic systems that have not yet found a wide application in the industry

Summary ITU-T Recommendation L.77 describes methods to install optical cables inside sewer ducts, which applies to both the cable installation and the pre-installation of an infrastructure, if requested. This Recommendation covers both man- and non-man-accessible sewer ducts. This Recommendation is not intended to address all of the safety concerns, if any, associated with its use. Therefore, it shall be the responsibility of the user of this Recommendation to establish appropriate health and safety practices and determine the applicability of regulatory limitations, if any, prior to its use.