Transducers differential transformer

Linear-Variable-Differential-Transformer and Reluctive Pressure Transducers. In ahnear-vatiable-differential-transformer (LVDT) pressure transducer, the pressure to be measured is fed to a Bourdon tube or diaphragm. The motion of this element is transferred to the... 

Of special interest in scale-control systems is the type in which the motion of the scale beam is sensed by a differential transformer or a group of load cells. The output of such devices is proportional to the displacement of the scale beam, which in turn is proportional to the amount of material in the weigh bucket. Many designs use loadsensing devices such as strain gauges or transducers. These eliminate the need for a scale-beam mechanism. The weigh vessel is mounted directly on the load-sensing devices. This provides many benefits in... 

Linear-variable-differential-transformer (LVDT) transducers, 20 652-653 Linear velocity, exponents of dimensions in absolute, gravitational, and engineering systems, 8 584t Lineatin, 24 473 Line-block coders, 7 691 Line-edge roughness (LER), 15 181 Line exposures, in photography, 19 209-210 Linen... 

An associated type of transducer is the Linear Variable Differential Transformer (LVDT) which is essentially a transformer with a single primary winding and two identical secondary windings wound on a tubular ferromagnetic former. The primary winding is energised by an a.c. source (see Fig. 6.13). 

Other types of transducers used in process measurements include mechanical drivers such as gear trains and electrical drivers such as a differential transformer or a Hall effect (semiconductor-based) sensor. 

Another type of inductance transducer, illustrated in Figure 8, utilizes two coils wound on a single tube and is commonly referred to as a Differential Transformer. 

The operation of proximity sensors can be based on a wide range of principles, including capacitance, induction, Hall and magnetic effects variable reluctance, linear variable differential transformer (LVDT), variable resistor mechanical and electromechanical limit switches optical, photoelectric, or fiber-optic sensors laser-based distance, dimension, or thickness sensors air gap sensors ultrasonic and displacement transducers. Their detection ranges vary from micrometers to meters, and their applications include the measurement of position, displacement, proximity, or operational limits in controlling moving components of valves and dampers. Either linear or angular position can be measured ... 

Linear variable differential transformer (LVDT, Fig. 2) is a device that produces voltage proportional to the position of a core rod inside a cylinder body. It measures displacement or a position of an object relative to some predefined zero location. On tablet presses, LVDTs are used to measure punch displacement and in-die thickness. They generally have very high precision and accuracy, but there are numerous practical concerns regarding improper mounting or maintenance of such transducers on tablet presses. 

Tensile and compressive tests were performed at room temperature with a tensile testing machine (DY25, Adamel-Lhomargy). For the tensile tests, strain measurements were performed with an extensometer (EX-10) at a strain rate of 3.3 x 10-4 s-1, using ISO-60 standard specimens. Samples of dimension 20 x 12 x 6 mm were deformed in a compression cage between polished steel plates. The nominal strain was determined by averaging the results from two linear variable differential transformer (LVDT) transducers. The strain rate used was 8.3 x 10"4 s-1. 

Allard E M 1962 Sound and pressure signals obtained from a single intracardiac transducer IRE Trans. Bio-Med. Electron. BME-9 74-7 van Citters R L 1966 Mutual inductance transducers Methods in Medical Research vol XI, ed R F Rushmer (Chicago Year Book), pp 26-30 Reddy N P and Kesavan S K 1988 Linear variable differential transformers Encyclopedia of Medical Devices and Instrumentation ed J G Webster (New York Wiley) pp 1800-6... 

Current generated in a transducing circuit such as photocell, differential transformer, strain gauge, bridge, radiation detector, capacitor, or inductor. 

Changes in the dimensions of a sample are detected by a mechanical, optical or electrical transducer although the transducer is usually a linear variable differential transformer (LVDT). The sample may be positioned either vertically or horizontally. The latter usually introduces friction between the sample and the support tube, which may be reduced to acceptable levels but never totally eliminated (l). Vertical dilatometers overcome the prob-... 

Linear position transducers The simplest form is a linear potentiometer, where the position of the slider is proportional to the output voltage. Linear variable differential transformers (LVDls) move a metal core between primary and secondary coils to produce a voltage proportional to core position. 

The third type transducer is very similar to the first type except the slug of a linear differentieJ. transformer or variable Inductance Is mounted on one diaphragm eind the coils of a differential transformer or inductance coil of a variable inductance is mounted on the other diaphragm. Differential pressure is then sensed by the relative movement between the coil and slug. 

The heart of this system is a pair of parallel, balanced sample support arms which oscillate freely around flexture pivots. Designed for low friction and precise balance, the natural frequency of the sample support system is less than 3 Hz, minimizing system contributions to damping. A schematic of this device is shown in Fig. 1. To make a measurement, a material of known dimensions is clamped between the two sample arms. The sample-arm-pivot system is oscillated at its resonant frequency by an electromechanical transducer. Frequency and amplitude of this oscillation are detected by a linear variable differential transformer (LVDT) positioned at the opposite end of the active arm. The LVDT provides a signal to an electromechanical transducer, which in turn keeps the sample oscillating at constant amplitude. 

Transducer - dii-s9r (1924) n. A device that transforms the value of a physical variable into an electrical signal, usually voltage or current. Examples are thermocouple, pressure transducer, linear variable differential transformer (a motion transducer), tachometer generator, and force cell. 

Displacements of the test specimen relative to the table or relative displacements between parts of the specimen are monitored either with Celesco draw wire displacement transducers or with Linear Variable Differential Transformers (LVDT), whichever is most convenient... 

FIGURE 18.2 Gross displacement transducers (a) potentiometers, (b) variable differential transformers (VDT), (c) synchros (typical connection), (d) resolvers (typical connection), (e) absolute position encoders, (f) code track for incremental position encoder. 

Figure 14.6. Schematic diagram of the three-point support flexural test h, sample thickness LVDT, Linear Variable Differential Transformer displacement transducer R = 46.75 mm [69]...

With a similar principle, the apparatus of Chompff uses Segel-Pochettino geometry if of Fig. 5-1) with a thin foil to contain the viscoelastic liquid between the cylinders. The displacement of the inner cylinder is measured by a differential transformer and the force on the outer cylinder by a ferroelectric ceramic transducer. The frequency range is from 1 to 2500 Hz, and good temperature control is provided over an extremely wide range. The moduli G and G" arp obtained as in equations 19 and 20, with the form factor b specified by equation 13. A related apparatus with continuous recording at constant frequency has been described by Date. ... 

The displacement transducer shown in Fig. 5 is generally one of two types. A linear-variable differential transformer (LVDT) is effectively a transformer where the coupling to the secondary winding(s) is a function of the position of a movable magnetic core. A capacitive displacement transducer (CDT) is a capacitor where the... 

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