Sirshendu Saha

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Papers by Sirshendu Saha

Study of a Noncontact Flow Transducer Using Semicylindrical Capacitive Sensor

IEEE Transactions on Instrumentation and Measurement, 2021

The fluid flow rate through a pipeline is a very important process variable in any process plant ... more The fluid flow rate through a pipeline is a very important process variable in any process plant that is required to be measured accurately. In this article, a new noncontact semicylindrical capacitive flow sensing technique has been developed and studied. The proposed capacitive sensor consists of two semicylindrical curved copper plates mounted on the outside surface of an insulating pipeline near the turbulence region produced at the junction of a larger diameter pipe and a smaller diameter pipe. Here the insulating pipeline section between the copper plates along with the flowing fluid acts as a composite dielectric material of the sensing capacitor. The semicylindrical curved copper plates along with two lead wires are rigidly mounted without any air gap on the larger diameter pipe using a thin layer of araldite. A mathematical relation between the sensor capacitance and flow rate is derived in this article. This capacitance is found to vary nonlinearly with flow rate and is measured using an op-amp-based DeSauty bridge-type transducer circuit where a similar capacitor with the same fluid at zero flow is used as a dummy capacitor. A prototype unit of the proposed transducer is designed, developed and tested experimentally. The static characteristic curves drawn from the experimental results are found to follow the derived mathematical equation to a very good extent with good repeatability.

Study of a modified non-contact Hall sensor-based flow transducer using centrifugal and momentum force principle

ISA Transactions, 2022

The paper describes a modified non-contact Hall sensor based centrifugal and momentum force type ... more The paper describes a modified non-contact Hall sensor based centrifugal and momentum force type flow transducer with simple design, low cost and rugged construction. In this transducer two identical permanent magnets are fixed on the two ends of the common balance lever on which sensing U-tube and dummy U-tube are placed at equal distances from the pivot. The movement of lever ends with variation of flow rate, changes the magnet positions with respect to the two identical Hall sensors fixed at two locations just below the magnets. Thus the outputs of the Hall sensors supplied from a stabilized DC source vary with the variation of flow rate. The difference between these outputs is a DC voltage signal non-linearly related with flow rate.

Study of an accurate electronic power measurement technique using modified current transformer and potential transformer

Transactions of the Institute of Measurement and Control, 2019

In high tension power measurement, potential transformer (PT) and current transformer (CT) are us... more In high tension power measurement, potential transformer (PT) and current transformer (CT) are used in order to reduce high tension voltage and current, respectively. But both PT and CT suffer from ratio error and phase angle error, which may produce severe error in power measurement. In the present paper, modified designs of PT and CT are combined to develop an electronic power measurement circuit in order to reduce the measurement errors. The modified PT and CT have reduced phase angle error and ratio error. In the power measurement circuit, the instantaneous product of the outputs of these PT and CT is determined by using a simple light emitting diode (LED)-light dependent register (LDR) or LED-LDR-based product circuit. The operation of the proto type power measurement unit designed in the present work has been experimentally tested and the measured outputs are compared with the readings of laboratory standard wattmeter. The experimental results are reported in the paper. Very g...

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A Temperature Compensated Non-Contact Pressure Transducer Using Hall Sensor and Bourdon Tube

IEEE Sensors Journal, 2019

The present paper describes, the design of a simple non-contact type pressure transducer using Bo... more The present paper describes, the design of a simple non-contact type pressure transducer using Bourdon tube and Hall sensor where the effect of atmospheric temperature is compensated. In this design, a pressure sensing Hall IC is fixed with the nonmagnetic aluminum casing of a Bourdon gauge in front of a tiny disc type permanent magnet rigidly attached with the free tip of the Bourdon tube. With the increase of pressure of the fluid inside the Bourdon tube, the free end along with the magnet moves towards the Hall sensor and the magnetic field intensity due to the magnet on the Hall sensor increases with increase of pressure. Due to this magnetic field, the outputs of Hall sensor and the transducer circuit consisting of a differential amplifier and an instrumentation amplifier, increase with the increase of pressure of fluid inside the Bourdon tube. The transducer circuit consists of a unity gain differential amplifier circuit where the output of a second identical temperature sensing Hall IC is subtracted from the pressure sensing Hall IC output in order to compensate the effect of ambient temperature in the proposed transducer. The theoretical equations describing the operation of the transducer are derived in the paper. The static characteristic curves of a prototype design of the transducer are determined experimentally. The experimental results are reported in the paper. The characteristics curves are found to follow the theoretical equations with good repeatability and are free from ambient temperature effect.

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Study of a Modified LVDT Type Displacement Transducer With Unlimited Range

IEEE Sensors Journal, 2018

The conventional LVDT is generally used as displacement transducer but has some limitations such ... more The conventional LVDT is generally used as displacement transducer but has some limitations such as small linear range, measurement errors due to stray capacitance effect, electromagnetic interference effect, and core loss effect. In this paper, a modified LVDT type displacement transducer has been proposed in order to overcome these limitations of conventional LVDT. The proposed LVDT will consist of only two identical coils instead of three coils of conventional LVDT. This design does not require any excitation coil. In this design, two identical coils wound on a former made of ferromagnetic material act as displacement sensing inductive coils with specially designed movable core. The design has been analyzed under three cases. It has been shown that the range of the displacement transducer is about 50% of the overall length of the sensor under two cases like conventional LVDT and is about 100% of the overall length of the sensor under the third case. So in this paper, a displacement transducer has been designed and tested experimentally considering only the third case with unlimited range equal to the entire length of the sensor. The transducer consists of an op-amp-based differential inductance measuring circuit and an output instrumentation amplifier. The performance equations of this sensor under three cases and of the transducer under third case are derived in the paper. The experimental results reported in the paper are found to follow the derived equations with very good linearity and repeatability.

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An improved technique of capacitance measurement of solar cells

Proceedings of the 2015 Third International Conference on Computer, Communication, Control and Information Technology (C3IT), 2015

It is very much important to design an efficient and reliable power conditioner with detailed stu... more It is very much important to design an efficient and reliable power conditioner with detailed study on measurement of AC parameter of solar cell (especially the cell capacitance). In this paper, we measured the capacitance of GaAs/Ge and Silicon (BSFR) solar cells under dark condition over a wide range of bias voltages using low level sine wave signal of desired amplitude. The approach of sinusoidal wave method offers the accurate and most economic way of studying the capacitance of semiconductor devices. Here frequency domain techniques have been used. It is shown that for GaAs/Ge solar cell, it exhibits only transition capacitance while Silicon (BSFR) solar cell exhibited both transition and diffusion capacitances.

Study of a Modified Capacitance-Type Level Transducer for Any Type of Liquid

IEEE Transactions on Instrumentation and Measurement, 2014

ABSTRACT The conventional capacitance-type liquid level sensor consists of an insulated solid met... more ABSTRACT The conventional capacitance-type liquid level sensor consists of an insulated solid metallic rod electrode immersed in the liquid contained in a metallic storage tank, or two such identical electrodes in a nonmetallic storage tank. Such metallic rods may suffer from the self-inductance effect which varies nonlinearly with the level. In this paper, we present a modified capacitance-type level sensor in which effect of self-inductance of the metallic rod has been eliminated. The theoretical equations describing the operation of the sensor are derived. The sensor is designed and tested experimentally and is found to follow the theoretical equations. The experimental results are also presented. A very good linearity of the sensor is observed.

An improved technique of measurement of high A.C. voltage

2014 First International Conference on Automation, Control, Energy and Systems (ACES), 2014

High a. c. voltage is generally measured by a potential transformer instead of an a.c. volt meter... more High a. c. voltage is generally measured by a potential transformer instead of an a.c. volt meter in order to avoid the hazards of high voltage. The conventional potential transformer is specially designed step down transformer where almost accurate voltage between primary and secondary is maintained to obtain output voltage directly proportional to input voltage. But this measurement suffers from ratio error and phase angle error, due to the effects of secondary current, magnetizing current and eddy current. In the present paper attempts have been made to reduce these currents by an improved design technique of the transformer. The technique has been utilized to fabricate a low voltage prototype unit. Its performance characteristics have been experimentally studied in a storage oscilloscope. The experimental results are reported in this paper. From these results a very good linear response with negligible phase angle error has been observed.