Resistance temperature detector

HT motors must have a minimum six numbers of resistance temperature detectors (RTDs) (See section 12.8). 

Embedded temperature detectors are resistance temperature detectors (RTDs) or resistance thermometers or thermocouples, built within the machine during manufacture at points that are not accessible when the machine has been assembled. This method is generally employed for the likely hot spots of a machine such as the slot portion and the overhangs of the stator windings. 

This is a later introduction in the sensing of temperature compared to the more conventional types of temperature devices available in an embedded temperature detector (ETD), such as a thermocouple or a resistance temperature detector (RTD) described below. Thermistors can be one of the following types ... 

Verifying temperature is the second most important aspect of any compressor operation. As with pressure, the basic form of measurement is a simple temperature gauge. The construction of the gauges is quite varied, ranging from a bimetallic device to the filled systems. When transmis sion is involved, the sensor becomes quite simple, taking the form v)l a thermocouple or a resistance temperature detector (RTD). The monitor does the translation from the native signal to a temperature readout ()r signal proportional to temperature. 

Resistance temperature detector. In the low-medium temperature range, thermometers based on resistometry are often used. A reference high-accuracy thermometer is the platinum resistance temperature detector which may be used as an interpolation standard in the temperature range from the triple point... 

Thermistors These are resistance temperature detectors composed of semiconductor materials. 

Temperature sensors, such as RTDs (resistance temperature detectors), thermocouples, and thermistors, can be installed directly in the thrust bearing to measure metal temperature. 

Metal Oxide-Polymer Thermistors. The variation of electrical properties with temperature heretofore described can be used to tremendous advantage. These so-called thermoelectric effects are commonly used in the operation of electronic temperature measuring devices such as thermocouples, thermistors, and resistance-temperature detectors (RTDs). A thermocouple consists of two dissimilar metals joined at one end. As one end of the thermocouple is heated or cooled, electrons diffuse toward... 

There are two principal classes of this type of sensor, viz. (i) resistance thermometers (resistance temperature detectors)—which are constructed from normal metallic conducting materials, and (ii) thermistors—which are bulk semiconductor sensors. 

The Resistance Temperature Detector (RTD) or Resistance Thermometer The variation of resistance with temperature 0 for metals can be expressed by ... 

Resistance Temperature Detector (RTD) Type Normal Operating Range (K.) Accuracy (K) Comments... 

Fic. 6.25. Typical resistance temperature detector element of circular cross-section ... 

Resistance temperature detector (RTD) Venturi Elastic element Chain gauge Mass spectrometry (MS)... 

Temperature is by far the more frequently measured state variable and is considered in some detail hereafter. Basic temperature measurement in a batch reactor must regard, at least, the reacting mixture and the heat exchange fluid. To this goal, the devices most widely used are thermocouples and resistance temperature detectors (RTD). 

Because temperature is one of the most important parameters of a material, many instruments have been developed to measure it. One type of detector used is the resistance temperature detector (RTD). The RTD is used at many DOE nuclear facilities to measure temperatures of the process or materials being monitored. 

Resistance temperature detectors (RTDs) are summarized below. 

FIGURE 6.15 Schematic drawings (top view) depicting (a) the capture and separation electrode, heater, and resistive temperature detector (RTD) module on the silicon substrate (b) the electrophoresis channel layout on the glass substrate and (c) the assembled device consisting of the glass channel bonded on top of the silicon substrate [95]. Reprinted with permission from Wiley-VCH Verlag. 

Whatever the scale or method of culture (T-flask, Schott bottle, spinner flask, or bioreactor), the temperature of the culture medium with which the cells are in contact is always a fundamental state variable, because it interferes with growth and the production process. However, it is a process variable that is easy to monitor and control. On a small scale the culture flask is usually put in a thermostatically controlled incubator, where the measured value of a thermometer sends a sign to turn the heating on or off ( on-off control ). In bioreactors, there are equivalent systems, as will be seen later. Usually, however, a resistance thermometer sensor type is used (resistance temperature detector or RTD), the electric... 

Thermocouples are usually not accurate enough for the precise measurement of temperature differences and are not fast enough to detect highspeed variations in temperature. Resistance temperature detectors (RTDs) can detect temperature differences of 5°C (10°F) at a measurement error of 0.02°C ( 0.04°F). If higher-speed response is desired, thermistors or infrared detectors should be considered. 

In the category of electronic thermometers, the thermocouples (TCs), resistance temperature detectors (RTDs), thermistors, integrated circuitry (IC), and radiation thermometers will be discussed in separate subsections. The IC and diode detectors will be discussed in connection with cryogenic thermometry. Their characteristics are shown in Figure 3.161. 

As was shown in Figure 3.159, cryogenic temperatures can be detected by integrated circuit diodes types K, T, and E thermocouples (TCs) class A and B resistance temperature detectors (RTDs) acoustic and ultrasonic thermometers germanium and carbon resistors and paramagnetic salts. As TCs and RTDs will be discussed in separate subsections, here the focus will be on the other sensors. 

Figure 2.1 Thermal behavior of a thermistor [1] and a platinum resistance temperature detector (RTD) [2],...

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