Small Electric Motor Research Articles

Design of a pipeline sensor-based platform for soil water content monitoring

This paper presents a sensor-based platform that travels through an underground pipeline system and monitors the soil water content in real time. It consists of a modified commercial soil water sensor (Diviner 2000), which is placed on two circular articulated wheeled bases, each of them driven by a small wheeled electric motor. An electronic module allows the user to control the platform by sending commands (move one step forward or backwards) from the ground station. Experiments were carried out in laboratory conditions in an artificial tank 10 m long by 0.6 m wide, and with a depth of 0.4 m (total volume 2.4 m3). The PVC pipelines were placed horizontally at depths of 0.1 m and 0.3 m under the soil surface. The sensor-based platform demonstrated very good mobility and produced records of the soil water content in the different horizons. The recorded values were then plotted as volumetric water content (m3 m−3) versus time. The application to a border irrigation case study provided the spatial variability of the water content, so that precise information about the soil environment was gathered. Also, in a drip irrigation case study, the sensor-based platform gave important information about the technical stage of the drip irrigation system. Thus, the measurement of soil water using the proposed method is more effective than measuring the soil water status at a single point and assuming soil homogeneity.

자동 IV 주사 유량 자동 제어 및 네트워크 모니터링

AbstractIntravenous (IV) injection is widely used to supply Ringer solution directly into a vein in hospital. Generally, a passive injection method has been used, which causes the inconsistent flow rate of fluid and inappropriate control of injection time by a patient. It leads to an unnecessary nurse's overwork and decrement of IV injection's effect. To solve these problems, flow control infusion pumps have been developed. But because of relatively heavy weight and high price, its usage has been limited. In the present study, a new automatic IV injection system is developed. It is installed with a small pressing mechanism driven by a small electric motor to regulate the flow rate by pressing tube. Proportional integral derivative (PID) feedback control algorithm is applied to control the electric motor. The system is smaller in size and uses lower power than the existing commercial product. The newly developed system is also installed with networking capability, which enables monitoring the status of several automatic IV injection system at the same time.

More motor, less power [electric motors

Better control over component-level electric motors could yield massive energy savings, and a two-pronged attack is yielding results across a range of products. Improvements to efficiency standards for small electric motors could easily outweigh the energy consumption reductions in computers and their displays from now until the end of 2035, according to a report published earlier this year by the American Council for an Energy-Efficient Economy (ACEEE). What's more, this does not include the motors built into other equipment, such as air conditioners and washing machines.

Magnet makeover

In ancient times, they were considered magical objects with supernatural powers. These days, we just stick them on our refrigerators. Yet those little magnets deserve our admiration more than ever. Take laptop computers, with their slim hard drives. It became possible to manufacture the motors for those drives only after the development of especially powerful permanent magnets in the early 1980s. Such muscular magnets are now found in many other places as well-various household appliances, cellphones, and the small electric motors that operate accessories in our cars, to name a few. They are also critical in the brawny electric motors that propel hybrid vehicles and in the generators attached to many wind turbines. So they can help both to reduce energy consumption and produce green electric power. Because the magnets themselves are hidden away, many of us tend to take them for granted. We shouldn't, especially not now. The manufacture of most high-performance magnets requires neodymium, a rare earth element that's in short supply. Almost all of the world's production comes from China, which has increasingly restricted exports to ensure that it has enough to satisfy its own needs. So the price of neodymium has been skyrocketing. If the trend continues, pretty soon we'll have a real crisis on our hands.

Improved Direct Torque Control of Permanent Magnet Synchronous Electrical Vehicle Motor with Proportional-Integral Resistance Estimator

Electric vehicles (EVs) require fast torque response and high drive efficiency. This paper describes a control scheme of fuzzy direct torque control of permanent magnet synchronous motor for EVs. This control strategy is extensively used in EV application. With direct torque control (DTC), the electromagnetic torque and stator flux can be estimated using the measured stator voltages and currents. The estimation depends on motor parameters, except for the stator resistance. The variation of stator resistance due to changes in temperature or frequency downgrades the performance of DTC, which is controlled by introducing errors in the estimated flux linkage vector and the electromagnetic torque. Thus, compensation for the effect of stator resistance variation becomes necessary. This work proposes the estimation of the stator resistance and its compensation using a proportional-integral estimation method. An electronic differential has been also used, which has the advantage of replacing loose, heavy, and inefficient mechanical transmission and mechanical differential with a more efficient, light, and small electric motors that are directly coupled to the wheels through a single gear or an in-wheel motor.

Thermal Fluid Process in a Small Universal Electric Motor

This paper presents an investigation of the heat transfer and fluid flow process in a small universal electric motor, which employs a stamped metal axial flow cooling fan. A three-dimensional conjugate computational model is developed. An experimental testing system is built to measure the flow rates of cooling air at various rotation speeds. The agreement between the experimental data and the model predictions is reasonably good. The numerical approach presents detailed flow structures, temperature distributions, and quantitative heat flux data. The cooling flowpath, heat transfer process, and the fluid driving of the cooling fan are analyzed. Suggestions for universal motor development and cooling design are given.

Listen up and get involved: Standing waves—The unbalanced motor and musical string.

The experiments that will be demonstrated are Standing Waves—The Unbalanced Motor and Standing Waves—Musical String. The unbalanced motor experiment involves a small electric motor that provides tension in the string. Students will observe the effect of holding the string and slowly sliding their hand toward the unbalanced motor. For the musical string experiment, students will observe musical intervals (do-me, do-sol, do-do, etc.) with a tensioned piano string and the science behind musical notes.

Effects of Plasma Washing on Characteristics of Small Emall Electric Motor

Effects of Plasma Washing on Characteristics of Small Emall Electric Motor

Automatic knee flexion in lower limb orthoses

Lower limb orthoses are often plagued by a high rejection rate, due both to the excessive effort demanded from their users and to the lack of aesthetics of the resulting gait. These factors are caused, to a great extent, by the fact that orthoses force the whole gait to be performed with the knee articulation in full extension. This work presents a light and compact device, with a low energy consumption, that can improve the performance and the gait aesthetics of knee-ankle-foot orthoses (known as KAFO). To do so, we explore the natural dynamics of the lower limb through a spring that is attached to a standard orthosis system. We also add control circuitry, a small electric motor, sensors and microprocessors to the standard orthosis, so that we can control the whole gait in a relatively natural manner. We have designed the system through a large set of simulations and have shown that the passive dynamics of the lower limb, driven by a burst of energy from a spring at the beginning of the swing phase, is sufficient to reduce the compensation mechanisms required during the gait with orthosis. Thus, this strategy is an alternative to existing solutions relying on functional electrical stimulation (FES), which suffers from limitations such as rapid muscle fatigue and difficult motion control. We describe the design of the device, the model adopted for the swing phase of the gait, the numerical simulations performed and the tests we have conducted.

A perching mechanism for micro aerial vehicles

Micro Aerial Vehicles (MAVs) with perching capabilities can be used to efficiently place sensors in aloft locations. A major challenge for perching is to build a lightweight mechanism that can be easily mounted on a MAV, allowing it to perch (attach and detach on command) to walls of different materials. To date, only very few systems have been proposed that aim at enabling MAVs with perching capabilities. Typically, these solutions either require a delicate dynamic flight maneuver in front of the wall or expose the MAV to very high impact forces when colliding head-first with the wall. In this article, we propose a 4.6 g perching mechanism that allows MAVs to perch on walls of natural and man-made materials such as trees and painted concrete facades of buildings. To do this, no control for the MAV is needed other than flying head-first into the wall. The mechanism is designed to translate the impact impulse into a snapping movement that sticks small needles into the surface and uses a small electric motor to detach from the wall and recharge the mechanism for the next perching sequence. Based on this principle, it damps the impact forces that act on the platform to avoid damage of the MAV. We performed 110 sequential perches on a variety of substrates with a success rate of 100%. The main contributions of this article are (i) the evaluation of different designs of perching, (ii) the description and formal modeling of a novel perching mechanism, and (iii) the demonstration and characterization of a functional prototype on a microglider. (See accompanying video and http://lis.epfl.ch/microglider/perching.mpg.)

Continuous-Flow, Rapid Lysis Devices for Biodefense Nucleic Acid Diagnostic Systems

Two mechanical lysis devices have been developed as compact, robust components to provide rapid sample preparation for nucleic acid diagnostic systems. One such component, known as the Micro Bead-Beater™ (μBB™, BBTM, Claremont BioSolutions, Upland, CA), is a compact device that is capable of ultrarapid lysis (>90% lysis in 30 s) of micro volumes (<80 μL) of Bacillus spores in a continuous-flow format or in a disposable single-tube format. The μBB is also capable of processing much larger volumes of solutions containing spores or vegetative cells using a continuous-flow mode. A second mechanical lysis device designed as a disposable component is the microfluidic bead blender, which uses a small electric motor to spin vanes within the bead-laden solution. DNA quantification results using dsDNA-binding fluorescence dyes and real-time PCR are presented, comparing the lysis of Bacillus subtilis spores using the μBB™ with other well-known lysis techniques. Nanoscale imaging results obtained using scanning electron microscopy and transmission electron microscopy on B. subtilis spores lyzed using the μBB™ are also presented

Enabling Coupled Quantitative Genomics and Proteomics Analyses from Rat Spinal Cord Samples

Translational research is progressing toward combined genomics and proteomics analyses of small and precious samples. In our analyses of spinal cord material, we systematically evaluated disruption and extraction techniques to determine an optimum process for the coupled analysis of RNA and protein from a single 5-mm segment of tissue. Analyses of these distinct molecular species were performed using microarrays and high resolution two-dimensional gels, respectively. Comparison of standard homogenization with automated frozen disruption (AFD) identified negligible differences in the relative abundance of genes (44) with all genes identified by either process. Analysis on either the Affymetrix or Applied Biosystems Inc. gene array platforms provided good correlations between the extraction techniques. In contrast, the AFD technique enabled identification of more unique proteins from spinal cord tissue than did standard homogenization. Furthermore use of an optimized CHAPS/urea extraction provided better protein recovery, as shown by quantitative two-dimensional gel analyses, than did solvent precipitation during TRIzol-based RNA extraction. Thus, AFD of tissue samples followed by protein and RNA isolation from separate aliquots of the frozen powdered sample is the most effective route to ensure full, quantitative analyses of both molecular entities.

Geometry effects on conjugate natural convection heat transfer in vertical eccentric annuli

PurposeTo explore the effect of the annulus geometrical parameters on the induced flow rate and the heat transfer under the conjugate (combined conduction and free convection) thermal boundary conditions with one cylinder heated isothermally while the other cylinder is kept at the inlet fluid temperature.Design/methodology/approachA finite‐difference algorithm has been developed to solve the bipolar boundary‐layer equations for the conjugate laminar free convection heat transfer in vertical eccentric annuli.FindingsNumerical results are presented for a fluid of Prandtl number, Pr=0.7 in eccentric annuli. The geometry parameters of NR2 and E (the fluid‐annulus radius ratio and the eccentricity, respectively) have considerable effects on the results.Practical implicationsApplications of the obtained results can be of value in the heat‐exchanger industry, in cooling of underground electric cables, and in cooling small vertical electric motors and generators.Originality/valueThe paper presents results that are not available in the literature for the problem of conjugate laminar free convection in open‐ended vertical eccentric annular channels. Geometry effects having been investigated by considering fluid annuli having radii ratios NR2=0.1 and 0.3, 0.5 and 0.7 and four values of the eccentricity E=0.1, 0.3, 0.5 and 0.7. Moreover, practical ranges of the solid‐fluid conductivity ratio (KR) and the wall thicknesses that are commonly available in pipe standards have been investigated. Such results are very much needed for design purposes of heat transfer equipment.

The conical pendulum: the tethered aeroplane

The introductory physics lab curriculum usually has one experiment on uniform circularmotion (UCM). Physics departments typically have several variable-speed rotators in storagethat, if they work, no longer work well. Replacing these rotators with new ones is costly,especially when they are only used once a year. This article describes how an inexpensive(≈$10) tethered aeroplane, powered by a small electric motor, can be used to study UCM. Theaeroplane is easy to see and entertaining to watch.For a given string length and air speed, a tethered aeroplane quickly finds a stable, horizontal,circular orbit. Using a digital video (DV) camcorder, VideoPoint Capture, QuickTimeplayer, metre sticks and a stopwatch, data on the aeroplane’s motion were obtained. Thelength of the string was varied from 120 to 340 cm while the air speed ranged from 200 to480 cm s−1. For each string length and air speed, the period of the orbit and the diameter of the pathwere carefully measured. Theoretical values of path radii were then calculated usingNewton’s second law. The agreement between experiment and theory was usually betterthan 2%.

Characterization of machines for processing of waste materials

The paper presents the machines for processing of waste materials in agriculture. There are many waste materials from which it is possible by means of suitable machines to obtain the product which can be favourably used. The aim of crushing of waste materials is to reduce their volume and to use them favourably. For crushing small waste wood and branches into matchwood, small tractor-driven machines and electric motor machines are used. Larger machines for the biomass preparation are more capable and more expensive; they have their own drive and a motor output of more than 200 kW. The paper discusses testing of the new crushing machine Terminator 5000S-181024 of Komptech make for different materials to be crushed. The test includes crushing of different types of materials of different densities by means of new crushing rolls. Capacity of the machine and the required split clearance for the individual type of material on the crushing roll are indicated. Further, the Terminator 5000S-181002 and the Crambo 5000 were mutually compared concerning capacity of waste wood crushing.

Maximum possible induced flow rates in open‐ended vertical eccentric annuli with uniform heat flux

PurposeObtaining the maximum possible flow rates that can be induced by free convection in open‐ended vertical eccentric annuli under fundamental thermal boundary conditions of the fourth kind (heating or cooling one of the annulus walls with a uniform heat flux while keeping the other wall at ambient temperature). Obtaining the maximum possible flow rates that can be induced by free convection in open‐ended vertical eccentric annuli under fundamental thermal boundary conditions of the fourth kind (heating or cooling one of the annulus walls with a uniform heat flux while keeping the other wall at ambient temperature).Design/methodology/approachThe fully‐developed laminar free convection momentum equation has been solved numerically using an analytical solution of the governing energy equation.FindingsResults are presented to show the effect of the annulus radius ratio and the dimensionless eccentricity on the induced flow rate, the total heat absorbed by the fluid, and the fully developed Nusselt numbers on the two boundaries of the annulus for a fluid of Prandtl number 0.7.Practical implicationsApplications of the obtained results can be of value in the heat‐exchanger industry, in cooling of underground electric cables, and in cooling small vertical electric motors and generators.Originality/valueThe paper presents a solution that is not available in the literature for the problem of fully developed free convection in open‐ended vertical eccentric annular channels under thermal boundary conditions of the fourth kind. Also presents the maximum possible induced flow rates, the total heat absorbed by the fluid, and the Nusselt numbers on the two boundaries of the annulus. The effects of N and E (the radius ratio and eccentricity, respectively) on these results are presented. Such results are very much needed for design purposes of heat transfer equipment.

Fingertip control

Dear Diary, I've known for some time what my project is going to be. It's based on a practical we did last year, about half way through the AS course. It was magic. By the end of the lesson, we all had small electric motors, which could be turned on by just touching two wires with a finger. It was such fun that we all took photos of the circuit with our mobiles and sent them off to our mates in the Common Room. The idea of using a tiny current in my skin to control a much larger current appeals.

Operation algorithm for a parallel hybrid electric vehicle with a relatively small electric motor

In this paper, operation algorithms for a parallel HEV equipped with a relatively small motor are investigated. For the HEV, the power assist and the equivalent fuel algorithms are proposed. In the power assist algorithm, an electric motor is used to assist the engine which provides the primary power source. In the equivalent fuel algorithm, the electric energy stored in the battery is considered to be an equivalent fuel, and an equivalent brake specific fuel consumption for the electric energy is proposed. From the equivalent fuel algorithm, distribution of the engine power and the motor power is determined to minimize the fuel consumption for a given battery state of charge (SOC) and a required vehicle power. It is found from the simulation results that the fuel economy and the final battery SOC depend on the motor discharge energy and it is the best way to charge the battery only by the regenerative braking, not by the engine to improve the overall fuel efficiency of the HEV with the relatively small motor.

Breathing new life into the biology classroom.

An increasing number of exciting experiments for teaching biology is becoming available, but teacher training and institutional reform are also needed to integrate them into curricula

Vacuum Bazookas, Electric Rainbow Jelly and 27 Other Saturday Science Projects

11R65. Vacuum Bazookas, Electric Rainbow Jelly and 27 Other Saturday Science Projects. - NA Downie (Air Prod and Chem, Blasingstoke, UK). Princeton UP, Princeton. 2001. 253 pp. Softcover. ISBN 0-691-00986-4. $18.95.Reviewed by A Nachman (4808 45th Street NW, Washington DC 20016).The book in question is intended (by the author) to motivate (or further motivate) youngsters to pursue science/technology. He does this by describing 29 projects (each description between 5 and 10 pages with quite nice figures) of various levels of difficulty (which he himself rates) that can be done at home. The author commendably provides reasonably clear instructions for making and then employing the devices in each case and further provides some little historical context for the device or the principle the device illustrates. He also provides some “Science and Math” narrative (in a few cases involving calculus which would not be communicable to youngsters) and a narrative called “The Surprising Parts” which confronts the subtleties of the phenomena within each project. It is these sections that elevate this book above the “Mr. Wizard” or “Mr. Nye the Science Guy” level.This reviewer believes that some of these projects (about 1/2) are indeed of interest to the ASME community either as a teaching aid (even for undergraduates) or for self-amusement. Interestingly neither of the two projects mentioned in the title rate highly with this reviewer. The Jell-O project involves mobility of certain colored gels under an electric field (the relative differences serves to spread them into a rainbow within a petri dish) while the Bazooka project, though indeed mechanical, is not very interesting (a T-shaped tube driven by a vacuum cleaner which can shoot ping-pong balls). More interesting are projects which demonstrate some (possibly) counterintuitive phenomena. These include a pole which is vibrated by a small electric motor (many projects require a small electric motor) and which has one or more washers which can thereby be made to slide “up” the pole as well as almost stand still. The title of Hovering Rings for this project is quite apt. The explanation in terms of nodes and traveling waves on the pole (and of course friction between the washers and the pole) is well written. A related project shows that a pendulum can be kept in the vertical (plumb bob end closest to the ceiling) position by the expedient of suitably vibrating the other end with a small electric motor. Those who have been exposed to serious nonlinear oscillations material would not be surprised, but undergraduates might be, and this is a demonstration that could be undertaken in a classroom. Once again the explanation is sound. There is a project (Fishy Boat) which, while not so easy to make (it requires having a model boat and being willing to “modify” it as instructed), is really interesting. It argues that the single oar Venetian gondola method for boat propulsion has some merit in that the back-and-forth motion is well matched by the workings of a steam engine and a real case could be made for using it to navigate weed infested swamps, since it has no propeller to get tangled and is quiet. The next project argues that one could replace the rudder in a ship with a rotating cylinder (Rotarudder) and exploit the Magnus effect. Not a new idea, but still the accompanying narrative is very good and sending undergraduates from an introductory fluids course to read these few pages will be rewarding to them. There is a project for guiding a mobile toy car using a light beam (a warm-up exercise for laser-guided bombs!), and this is actually an excellent project for an introductory class in control theory—this reviewer regards this as the best project in this book—and another for cracking nuts using a snapped string (cracks the shell without crushing the meat). The discussion on the forces generated by such a suitably deployed string is just the sort of thing an undergraduate engineering student needs to read. The nonmechanical projects are also fun to read. This reviewer especially liked the toothless gearwheels made from magnets and the homemade amplifier. While this reviewer thinks every person who teaches general science (and especially physics) in any grade up to 12 should obtain Vacuum Bazookas, Electric Rainbow Jelly and 27 Other Saturday Science Projects, he cannot make the same recommendation to the AMR reader. He can only say that this book is entertaining and edifying and is not expensive, so if the AMR reader has the slightest inclination toward books such as this one, then the impulse to buy should not be stifled.