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Article: Major appliance. A major appliance is a non-portable or semi-portable machine used for routine housekeeping tasks such as cooking, washing laundry, or food preservation. Such appliances are sometimes collectively known as white goods, as the products were traditionally white in colour, although a variety of co... | Wikipedia - Major appliance - Summary | 243 | 1,391 | null |
Article: Mechanical filter. A mechanical filter is a signal processing filter usually used in place of an electronic filter at radio frequencies. Its purpose is the same as that of a normal electronic filter: to pass a range of signal frequencies, but to block others. The filter acts on mechanical vibrations which are ... | Wikipedia - Mechanical filter - Summary | 322 | 1,850 | null |
For example, filtering of audio frequency response in the design of loudspeaker cabinets can be achieved with mechanical components. In the electrical application, in addition to mechanical components which correspond to their electrical counterparts, transducers are needed to convert between the mechanical and electri... | Wikipedia - Mechanical filter - Summary | 203 | 1,168 | null |
Section: Elements. The elements of a passive linear electrical network consist of inductors, capacitors and resistors which have the properties of inductance, elastance (inverse capacitance) and resistance, respectively. The mechanical counterparts of these properties are, respectively, mass, stiffness and damping. In ... | Wikipedia - Mechanical filter - Elements | 339 | 1,738 | null |
Hence, M → C , S → 1/L , D → G where G is electrical conductance (the reciprocal of resistance, if there is no reactance). Equivalent circuits produced by this scheme are similar, but are the dual impedance forms whereby series elements become parallel, capacitors become inductors, and so on. Circuit diagrams using t... | Wikipedia - Mechanical filter - Elements | 346 | 1,728 | null |
Section: History > Harmonic telegraph. Mechanical filter design was developed by applying the discoveries made in electrical filter theory to mechanics. However, a very early example (1870s) of acoustic filtering was the "harmonic telegraph", which arose precisely because electrical resonance was poorly understood but ... | Wikipedia - Mechanical filter - History > Harmonic telegraph | 259 | 1,445 | null |
Section: History > Mechanical equivalent circuits. Once the basics of electrical network analysis began to be established, it was not long before the ideas of complex impedance and filter design theories were carried over into mechanics by analogy. Kennelly, who was also responsible for introducing complex impedance, a... | Wikipedia - Mechanical filter - History > Mechanical equivalent circuits | 343 | 1,442 | null |
These equations can be expressed as a matrix relationship in much the same way as the z-parameters of a two-port network in electrical theory, to which this is entirely analogous: [ V F ] = [ z 11 z 12 z 21 z 22 ] [ I v ] {\displaystyle {\begin{bmatrix}V\\F\end{bmatrix}}={\begin{bmatrix}z_{11}&z_{12}\\z_{21}&z_{22}\end... | Wikipedia - Mechanical filter - History > Mechanical equivalent circuits | 337 | 1,209 | null |
Section: History > Sound reproduction. An early application of these new theoretical tools was in phonographic sound reproduction. A recurring problem with early phonograph designs was that mechanical resonances in the pickup and sound transmission mechanism caused excessively large peaks and troughs in the frequency r... | Wikipedia - Mechanical filter - History > Sound reproduction | 338 | 1,823 | null |
In this theory, filter design is viewed essentially as an impedance matching problem. More advanced filter theory was brought to bear on this problem by Norton in 1929 at Bell Labs. Norton followed the same general approach though he later described to Darlington the filter he designed as being "maximally flat". Norton... | Wikipedia - Mechanical filter - History > Sound reproduction | 325 | 1,610 | null |
Section: History > Volume production. Modern mechanical filters for intermediate frequency (IF) applications were first investigated by Robert Adler of Zenith Electronics who built a 455 kHz filter in 1946. The idea was taken up by Collins Radio Company who started the first volume production of mechanical filters from... | Wikipedia - Mechanical filter - History > Volume production | 252 | 1,404 | null |
Section: Transducers > Magnetostrictive. A magnetostrictive material is one which changes shape when a magnetic field is applied. In reverse, it produces a magnetic field when distorted. The magnetostrictive transducer requires a coil of conducting wire around the magnetostrictive material. The coil either induces a ma... | Wikipedia - Mechanical filter - Transducers > Magnetostrictive | 331 | 1,537 | null |
Section: Transducers > Piezoelectric. A piezoelectric material is one which changes shape when an electric field is applied. In reverse, it produces an electric field when it is distorted. A piezoelectric transducer, in essence, is made simply by plating electrodes on to the piezoelectric material. Early piezoelectric ... | Wikipedia - Mechanical filter - Transducers > Piezoelectric | 342 | 1,522 | null |
Section: Resonators. It is possible to achieve an extremely high Q with mechanical resonators. Mechanical resonators typically have a Q of 10,000 or so, and 25,000 can be achieved in torsional resonators using a particular nickel-iron alloy. This is an unreasonably high figure to achieve with LC circuits, whose Q is li... | Wikipedia - Mechanical filter - Resonators | 346 | 1,631 | null |
Section: Resonators > Resonator modes. It is usually possible for a mechanical part to vibrate in a number of different modes, however the design will be based on a particular vibrational mode and the designer will take steps to try to restrict the resonance to this mode. As well as the straightforward longitudinal mod... | Wikipedia - Mechanical filter - Resonators > Resonator modes | 221 | 1,097 | null |
Section: Circuit designs. There are a great many combinations of resonators and transducers that can be used to construct a mechanical filter. A selection of some of these is shown in the diagrams. Figure 6 shows a filter using disc flexural resonators and magnetostrictive transducers. The transducer drives the centre ... | Wikipedia - Mechanical filter - Circuit designs | 320 | 1,431 | null |
Figure 9 shows a filter using drumhead mode resonators. The edges of the discs are fixed to the casing of the filter (not shown in the diagram) so the vibration of the disc is in the same modes as the membrane of a drum. Collins calls this type of filter a disc wire filter. The various types of resonator are all partic... | Wikipedia - Mechanical filter - Circuit designs | 340 | 1,639 | null |
Section: Circuit designs > Semi-lumped designs. Frequencies of the order of megahertz (MHz) are above the usual range for mechanical filters. The components start to become very small, or alternatively the components are large compared to the signal wavelength. The lumped-element model described above starts to break d... | Wikipedia - Mechanical filter - Circuit designs > Semi-lumped designs | 346 | 1,728 | null |
The resonators are disc flexural resonators similar to those shown in figure 6, except that these are energised from an edge, leading to vibration in the fundamental flexural mode with a node in the centre, whereas the figure 6 design is energised in the centre leading to vibration in the second flexural mode at resona... | Wikipedia - Mechanical filter - Circuit designs > Semi-lumped designs | 253 | 1,156 | null |
Section: Circuit designs > Bridging wires. Bridging wires are rods that couple together resonators that are not adjacent. They can be used to produce poles of attenuation in the stopband. This has the benefit of increasing the stopband rejection. When the pole is placed near the passband edge, it also has the benefit o... | Wikipedia - Mechanical filter - Circuit designs > Bridging wires | 333 | 1,585 | null |
Section: Microelectromechanical filters. A new technology emerging in mechanical filtering is microelectromechanical systems (MEMS). MEMS are very small micromachines with component sizes measured in micrometres (μm), but not as small as nanomachines. These filters can be designed to operate at much higher frequencies ... | Wikipedia - Mechanical filter - Microelectromechanical filters | 348 | 1,569 | null |
Section: Adjustment. The precision applications in which mechanical filters are used require that the resonators are accurately adjusted to the specified resonance frequency. This is known as trimming and usually involves a mechanical machining process. In most filter designs, this can be difficult to do once the reson... | Wikipedia - Mechanical filter - Adjustment | 331 | 1,707 | null |
Article: Mechanical–electrical analogies. Mechanical–electrical analogies are the representation of mechanical systems as electrical networks. At first, such analogies were used in reverse to help explain electrical phenomena in familiar mechanical terms. James Clerk Maxwell introduced analogies of this sort in the 19t... | Wikipedia - Mechanical–electrical analogies - Summary | 327 | 1,881 | null |
Mechanical–electrical analogies are developed by finding relationships between variables in one domain that have a mathematical form identical to variables in the other domain. There is no one, unique way of doing this; numerous analogies are theoretically possible, but there are two analogies that are widely used: the... | Wikipedia - Mechanical–electrical analogies - Summary | 329 | 1,752 | null |
Section: Applications. Mechanical–electrical analogies are used to represent the function of a mechanical system as an equivalent electrical system by drawing analogies between mechanical and electrical parameters. A mechanical system by itself can be so represented, but analogies are of greatest use in electromechanic... | Wikipedia - Mechanical–electrical analogies - Applications | 331 | 1,862 | null |
Section: Forming an analogy. Electrical systems are commonly described by means of a circuit diagram. These are network diagrams that describe the topology of the electrical system using a specialised graph notation. The circuit diagram does not try to represent the true physical dimensions of the electrical components... | Wikipedia - Mechanical–electrical analogies - Forming an analogy | 338 | 1,760 | null |
There is a wide choice of variables that can be used, but most commonly used are a power conjugate pair of variables (described below) and the pair of Hamiltonian variables derived from these. There is a limit to the applicability of this lumped element model. The model works well if the components are small enough tha... | Wikipedia - Mechanical–electrical analogies - Forming an analogy | 350 | 1,813 | null |
In the electrical domain, a transmission line, a basic distributed element component, can be included in the model with the introduction of the additional element of electrical length. The transmission line is a special case because it is invariant along its length and hence the full geometry need not be modelled. Anot... | Wikipedia - Mechanical–electrical analogies - Forming an analogy | 181 | 1,013 | null |
Section: Forming an analogy > Power conjugate variables. The power conjugate variables are a pair of variables whose product is power. In the electrical domain the power conjugate variables chosen are invariably voltage (v) and current (i). Thus, the power conjugate variables in the mechanical domain are analogs. Howev... | Wikipedia - Mechanical–electrical analogies - Forming an analogy > Power conjugate variables | 262 | 1,283 | null |
The Hamiltonian variables in the electrical domain are charge (q) and flux linkage (λ) because, ∂ H ∂ q = − d λ d t = v {\displaystyle {\frac {\partial {\mathcal {H}}}{\partial q}}=-{\frac {d\lambda }{dt}}=v} (Faraday's law of induction) and, ∂ H ∂ λ = d q d t = i {\displaystyle {\frac {\partial {\mathcal {H}}}{\partia... | Wikipedia - Mechanical–electrical analogies - Forming an analogy > Hamiltonian variables | 333 | 971 | null |
Section: Classes of analogy. There are two principal classes of analogy in use. The impedance analogy (also called the Maxwell analogy) preserves the analogy between mechanical, acoustical and electrical impedance but does not preserve the topology of networks. The mechanical network is arranged differently to its anal... | Wikipedia - Mechanical–electrical analogies - Classes of analogy | 301 | 1,704 | null |
Section: Classes of analogy > Impedance analogies. Impedance analogies, also called the Maxwell analogy, classify the two variables making up the power conjugate pair as an effort variable and a flow variable. The effort variable in an energy domain is the variable analogous to force in the mechanical domain. The flow ... | Wikipedia - Mechanical–electrical analogies - Classes of analogy > Impedance analogies | 336 | 1,670 | null |
Section: Classes of analogy > Through and across analogies. Through and across analogies, also called the Trent analogy, classify the two variables making up the power conjugate pair as an across variable and a through variable. The across variable is a variable that appears across the two terminals of an element. The ... | Wikipedia - Mechanical–electrical analogies - Classes of analogy > Through and across analogies | 307 | 1,587 | null |
Section: Classes of analogy > Other energy domains. The electrical analogy can be extended to many other energy domains. In the field of sensors and actuators, and for control systems using them, it is a common method of analysis to develop an electrical analogy of the entire system. Since sensors can be sensing a vari... | Wikipedia - Mechanical–electrical analogies - Classes of analogy > Other energy domains | 294 | 1,546 | null |
Section: Transducers. A transducer is a device that takes energy from one domain as input and converts it to another energy domain as output. They are often reversible, but are rarely used in that way. Transducers have many uses and there are many kinds, in electromechanical systems they can be used as actuators and se... | Wikipedia - Mechanical–electrical analogies - Transducers | 346 | 1,697 | null |
Section: History. James Clerk Maxwell developed very detailed mechanical analogies of electrical phenomena. He was the first to associate force with voltage (1873) and consequently is usually credited with founding the impedance analogy. This was the earliest mechanical–electrical analogy. However, the term impedance w... | Wikipedia - Mechanical–electrical analogies - History | 348 | 1,928 | null |
According to Warren P. Mason the efficiency of ship electric foghorns grew from less than one per cent to 50 per cent. The bandwidth of mechanical phonographs grew from three to five octaves when the mechanical parts of the sound transmission were designed as if they were the elements of an electric filter (see also Me... | Wikipedia - Mechanical–electrical analogies - History | 257 | 1,379 | null |
Article: Mechatronics. Mechatronics engineering, also called mechatronics, is the synergistic integration of mechanical, electrical, and computer systems employing mechanical engineering, electrical engineering, electronic engineering and computer engineering, and also includes a combination of robotics, computer scien... | Wikipedia - Mechatronics - Summary | 333 | 1,636 | null |
Section: Description. A mechatronics engineer unites the principles of mechanics, electrical, electronics, and computing to generate a simpler, more economical and reliable system. Engineering cybernetics deals with the question of control engineering of mechatronic systems. It is used to control or regulate such a sys... | Wikipedia - Mechatronics - Description | 210 | 1,120 | null |
Section: Subdisciplines > Mechanical. Mechanical engineering is an important part of mechatronics engineering. It includes the study of mechanical nature of how an object works. Mechanical elements refer to mechanical structure, mechanism, thermo-fluid, and hydraulic aspects of a mechatronics system. The study of therm... | Wikipedia - Mechatronics - Subdisciplines > Mechanical | 323 | 1,592 | null |
Section: Subdisciplines > Electronics and electricals. Electronics and telecommunication engineering specializes in electronics devices and telecom devices of a mechatronics system. A mechatronics engineer specialized in electronics and telecommunications have knowledge of computer hardware devices. The transmission of... | Wikipedia - Mechatronics - Subdisciplines > Electronics and electricals | 273 | 1,578 | null |
Section: Subdisciplines > Robotics. Robotics is one of the newest emerging subfield of mechatronics. It is the study of robots and how they are manufactured and operated. Since 2000, this branch of mechatronics is attracting a number of aspirants. Robotics is interrelated with automation because here also not much huma... | Wikipedia - Mechatronics - Subdisciplines > Robotics | 164 | 812 | null |
Section: Subdisciplines > Computer. The Internet of things (IoT) is the inter-networking of physical devices, embedded with electronics, software, sensors, actuators, and network connectivity which enable these objects to collect and exchange data. IoT and mechatronics are complementary. Many of the smart components as... | Wikipedia - Mechatronics - Subdisciplines > Computer | 221 | 1,124 | null |
Article: Mobility analogy. The mobility analogy, also called admittance analogy or Firestone analogy, is a method of representing a mechanical system by an analogous electrical system. The advantage of doing this is that there is a large body of theory and analysis techniques concerning complex electrical systems, espe... | Wikipedia - Mobility analogy - Summary | 304 | 1,748 | null |
Section: Elements. Before an electrical analogy can be developed for a mechanical system, it must first be described as an abstract mechanical network. The mechanical system is broken down into a number of ideal elements each of which can then be paired with an electrical analogue. The symbols used for these mechanical... | Wikipedia - Mobility analogy - Elements | 277 | 1,499 | null |
Section: Elements > Resistance. The mechanical analogy of electrical resistance is the loss of energy of a moving system through such processes as friction. A mechanical component analogous to a resistor is a shock absorber and the property analogous to inverse resistance (conductance) is damping (inverse, because elec... | Wikipedia - Mobility analogy - Elements > Resistance | 199 | 892 | null |
Section: Elements > Inductance. The mechanical analogy of inductance in the mobility analogy is compliance. It is more common in mechanics to discuss stiffness, the inverse of compliance. A mechanical component analogous to an inductor is a spring. An inductor is governed by the constitutive equation, v = L d i d t {\d... | Wikipedia - Mobility analogy - Elements > Inductance | 267 | 909 | null |
Section: Elements > Capacitance. The mechanical analogy of capacitance in the mobility analogy is mass. A mechanical component analogous to a capacitor is a large, rigid weight or a mechanical Inerter. A capacitor is governed by the constitutive equation, i = C d v d t {\displaystyle i=C{\frac {dv}{dt}}} The analogous ... | Wikipedia - Mobility analogy - Elements > Capacitance | 220 | 705 | null |
Section: Elements > Inertance. A curious difficulty arises with mass as the analogy of an electrical element. It is connected with the fact that in mechanical systems the velocity of the mass (and more importantly, its acceleration) is always measured against some fixed reference frame, usually the earth. Considered as... | Wikipedia - Mobility analogy - Elements > Inertance | 189 | 913 | null |
The two terminals of an inerter, unlike a mass, are allowed to have two different, arbitrary velocities and accelerations. The constitutive equation of an inerter is given by, F = B ( d u 2 d t − d u 1 d t ) = B d Δ u d t {\displaystyle F=B\left({\frac {du_{\mathrm {2} }}{dt}}-{\frac {du_{\mathrm {1} }}{dt}}\right)=B{\... | Wikipedia - Mobility analogy - Elements > Inertance | 336 | 1,223 | null |
Energy provided in pushing the plunger in will be returned when the plunger moves in the opposite direction, hence the device stores energy rather than dissipates it just like a block of mass. However, the actual mass of the inerter can be very small, an ideal inerter has no mass. Two points on the inerter, the plunger... | Wikipedia - Mobility analogy - Elements > Inertance | 267 | 1,270 | null |
Section: Elements > Transducers. Electromechanical systems require transducers to convert between the electrical and mechanical domains. They are analogous to two-port networks and like those can be described by a pair of simultaneous equations and four arbitrary parameters. There are numerous possible representations,... | Wikipedia - Mobility analogy - Elements > Transducers | 306 | 1,137 | null |
Section: Improvements. While the early results were successful, the RoboTuna was not able to replicate the bursts of acceleration that real tuna were able to manage. Researchers improved the design using a genetic algorithm, in which the best systems will "get to have virtual offspring", according to researcher David B... | Wikipedia - RoboTuna - Improvements | 158 | 809 | null |
Article: Rotary encoder. A rotary encoder, also called a shaft encoder, is an electro-mechanical device that converts the angular position or motion of a shaft or axle to analog or digital output signals. There are two main types of rotary encoder: absolute and incremental. The output of an absolute encoder indicates t... | Wikipedia - Rotary encoder - Summary | 179 | 874 | null |
Section: Technologies. Mechanical: Also known as conductive encoders. A series of circumferential copper tracks etched onto a PCB is used to encode the information via contact brushes sensing the conductive areas. Mechanical encoders are economical but susceptible to mechanical wear. They are common in human interfaces... | Wikipedia - Rotary encoder - Technologies | 329 | 1,584 | null |
Section: Basic types > Absolute. An absolute encoder maintains position information when power is removed from the encoder. The position of the encoder is available immediately on applying power. The relationship between the encoder value and the physical position of the controlled machinery is set at assembly; the sys... | Wikipedia - Rotary encoder - Basic types > Absolute | 174 | 889 | null |
Section: Absolute encoder > Absolute rotary encoder > Mechanical absolute encoders. A metal disc containing a set of concentric rings of openings is fixed to an insulating disc, which is rigidly fixed to the shaft. A row of sliding contacts is fixed to a stationary object so that each contact wipes against the metal di... | Wikipedia - Rotary encoder - Absolute encoder > Absolute rotary encoder > Mechanical absolute encoders | 216 | 1,038 | null |
Section: Absolute encoder > Absolute rotary encoder > Magnetic absolute encoders. The magnetic encoder uses a series of magnetic poles (2 or more) to represent the encoder position to a magnetic sensor (typically magneto-resistive or Hall Effect). The magnetic sensor reads the magnetic pole positions. This code can be ... | Wikipedia - Rotary encoder - Absolute encoder > Absolute rotary encoder > Magnetic absolute encoders | 331 | 1,551 | null |
Section: Absolute encoder > Ways of encoding shaft position > Standard binary encoding. An example of a binary code, in an extremely simplified encoder with only three contacts, is shown below. In general, where there are n contacts, the number of distinct positions of the shaft is 2n. In this example, n is 3, so there... | Wikipedia - Rotary encoder - Absolute encoder > Ways of encoding shaft position > Standard binary encoding | 322 | 1,381 | null |
Section: Absolute encoder > Ways of encoding shaft position > Single-track Gray encoding. If the designer moves a contact to a different angular position (but at the same distance from the center shaft), then the corresponding "ring pattern" needs to be rotated the same angle to give the same output. If the most signif... | Wikipedia - Rotary encoder - Absolute encoder > Ways of encoding shaft position > Single-track Gray encoding | 187 | 878 | null |
Section: Incremental encoder. The rotary incremental encoder is the most widely used of all rotary encoders due to its ability to provide real-time position information. The measurement resolution of an incremental encoder is not limited in any way by its two internal, incremental movement sensors; one can find in the ... | Wikipedia - Rotary encoder - Incremental encoder | 303 | 1,472 | null |
A rotary incremental encoder has two output signals, A and B, which issue a periodic digital waveform in quadrature when the encoder shaft rotates. This is similar to sine encoders, which output sinusoidal waveforms in quadrature (i.e., sine and cosine), thus combining the characteristics of an encoder and a resolver. ... | Wikipedia - Rotary encoder - Incremental encoder | 325 | 1,524 | null |
Section: Career. Shchokin received his primary and secondary education in Ukraine. He received his Engineering Diploma from Odessa Polytechnic Institute in 1967. From 1976 until 2001, Shchokin taught Theoretical Mechanics, Mechanics of Machines, Resistance of Materials, Applied Mechanics, Machine Design, Robotics and A... | Wikipedia - Borys Shchokin - Career | 255 | 1,365 | null |
Section: Effects of SCR values. Higher SCR requires lower reactance X S {\displaystyle X_{S}} that in practice means a larger air gap. Both high and low levels of SCR have their benefits: low SCR: in case of a short circuit, the current is proportional to SCR, therefore generators with low SCR require less protection a... | Wikipedia - Short circuit ratio (synchronous generator) - Effects of SCR values | 347 | 1,606 | null |
Section: Effects of construction. The larger the SCR, the smaller is alternator reactance (Xd) and inductance Ld. This is the result of larger air gaps in generator design (As in Hydro generators or Salient Pole Machines). It results into Machine loosely coupled to the grid, and its response will be slow. This increase... | Wikipedia - Short circuit ratio (synchronous generator) - Effects of construction | 254 | 1,190 | null |
Section: History and origins. While spinmechatronics has been recognised only recently (2008) as an independent field, hybrid spin-mechanical system development dates back to the early nineteen-nineties, with devices combining spintronics and micromechanics emerging at the turn of the twenty-first century. One of the l... | Wikipedia - Spinmechatronics - History and origins | 340 | 1,805 | null |
Section: Key constitutive technologies > Micro- and nano- mechatronics. MEMS: micro-electromechanical systems are the key ingredient of micro-mechatronics. Micro-electromechanical systems are – as the name suggests – devices with significant dimensions in the micrometre regime or less. Highly suited to integration with... | Wikipedia - Spinmechatronics - Key constitutive technologies > Micro- and nano- mechatronics | 267 | 1,313 | null |
Section: Key constitutive technologies > Spintronics. Spintronic magnetoresistance is a major scientific and commercial success story. Today, most families own a spintronic device: the giant-magnetoresistive (GMR) hard disk read head in their computer. The science that gave rise to this phenomenal business opportunity ... | Wikipedia - Spinmechatronics - Key constitutive technologies > Spintronics | 166 | 791 | null |
Section: Operation. In microwave cooking, susceptors are built into paper packaging of certain foods, where they absorb microwaves which penetrate the packaging. This process raises the susceptor patch temperature to levels where it may then heat food by conduction or by infrared radiation. Conduction heating occurs wi... | Wikipedia - Susceptor - Operation | 243 | 1,145 | null |
Section: Design and use. Susceptors are usually made of metallised film, ceramics or metals (such as aluminium flakes). Susceptors meant to heat foods by direct conduction may be seen in the gray lining of packaging directly holding the food, and generally in good contact with it. For this reason, products meant to be ... | Wikipedia - Susceptor - Design and use | 296 | 1,387 | null |
Section: Safety sensors. A door operator may use sensors to prevent the door from coming into contact with a user. Full Energy operators require at least 3 sensors. Low-energy operators are not required to have safety sensors, as the door is allowed to come in contact with a user, given that the kinetic energy of the m... | Wikipedia - Swing-door operator - Safety sensors | 342 | 1,626 | null |
In that case, the operator stops the door. The sensitivity of infrared sensors must be reduced at the end of the opening angle, if it starts seeing a wall next to the door, so it may not confuse it with a user. Laser based sensors increase the safety by learning the surroundings of the door and dynamically adapt their ... | Wikipedia - Swing-door operator - Safety sensors | 155 | 752 | null |
Section: Opening technologies. The majority of the operators open the door directly or through an arm. Overhead concealed mount—the operator is mounted above the door and rotates the door directly, through its pivot. Surface mount, push (scissor arm)—the operator is mounted on the wall above the door, on the approach s... | Wikipedia - Swing-door operator - Opening technologies | 206 | 947 | null |
Section: Internal technologies. Operators are powered by an electric motor. They differ in how they use the motor's energy to open the door. Operators use various internal technologies. Some are built on top of a standard door closer. To open the door, the operator forces the closer in the opening direction. Then, the ... | Wikipedia - Swing-door operator - Internal technologies | 330 | 1,535 | null |
Typically, the compressor can be located up to 200 feet away ensuring that noise is not a factor. A typical life expectancy of a pneaumtic system is 10–15 years except the compressor. Best application of a pneumatic system is in a residential environment where usage is limited to 30–40 times a day. Of the electromechan... | Wikipedia - Swing-door operator - Internal technologies | 205 | 957 | null |
Section: Classification. Sensors used in the automatic door industry typically fall into four categories: Microwave sensors used to detect motion of a person as they approach an automatic door, Reflective optical sensors that are mounted on the door header, and detect the presence of a person in the door path Camera ba... | Wikipedia - Triangulation sensor - Classification | 155 | 836 | null |
Section: Functionality. In most cases, an optical triangulation sensor is mounted near the top of the swinging door frame, inside a long extruded aluminum tube with an optical window facing the floor. An 880 nm LED light source emits a collimated, near-infrared light beam. The beam bounces off the floor and is received... | Wikipedia - Triangulation sensor - Functionality | 262 | 1,283 | null |
Article: V curve. In synchronous machines, the V curve (also spelled as V-curve) is the graph showing the relation of armature current as a function of field current in synchronous motors keeping the load constant. The name comes from an observation made by W. M. Mordey in 1893 that the curve resembles a letter V. The ... | Wikipedia - V curve - Summary | 334 | 1,272 | null |
At the low values of the field current, the power factor is low, so the armature current is high (and lagging). As the field current increases, the power factor increases too, until the unity power factor is reached (the armature current decreases to its minimum when the motor reaches this normal excitation). If the fi... | Wikipedia - V curve - Summary | 190 | 837 | null |
Article: Vapor etching. Vapor etching refers to a process used in the fabrication of Microelectromechanical systems (MEMS) and Nanoelectromechanical systems (NEMS). Sacrificial layers are isotropically etched using gaseous acids such as Hydrogen fluoride and Xenon difluoride to release the free standing components of t... | Wikipedia - Vapor etching - Summary | 205 | 957 | null |
Section: HF vapor etching > Etch chemistry > Etch reaction with water catalyst. If water is used, the H2O is adsorbed at the SiO2 surface and forms silanol groups can never form.SiO2 + 2 H2O → Si(OH)4 The HF reacts with the silanol groups and forms SiF4 and H2O according to the following reaction.Si(OH)4 + 4 HF → SiF4 ... | Wikipedia - Vapor etching - HF vapor etching > Etch chemistry > Etch reaction with water catalyst | 153 | 562 | null |
Section: HF vapor etching > Etch chemistry > Etch reaction with alcohol catalyst. Alternatively, different alcohols such as methanol, ethanol, 1-propanol or IPA can be used to initiate the reaction. An example for this reaction, using methanol (CH3OH) is given below. Firstly the HF and the methanol are absorbed to the ... | Wikipedia - Vapor etching - HF vapor etching > Etch chemistry > Etch reaction with alcohol catalyst | 347 | 983 | null |
Section: XeF2 vapor etching > Etch systems. The synthesis of XeF2 is an endothermic process which results in a white powder which sublimes at low pressures. (P < 4 Torr) The low vapor pressure allowed early researchers and engineers to use it in comparatively simple set ups. Modern vapour etch tools are more sophistica... | Wikipedia - Vapor etching - XeF2 vapor etching > Etch systems | 163 | 760 | null |
Section: XeF2 vapor etching > Etch chemistry. The general etch reaction is summarized by the following equation.2 XeF2 + Si → SiF4 + 2 XeThe detailed etch kinetic is more complex reaction consisting of four steps. After the etchant has been mass transported to the silicon surface, the xenon difluoride is absorbed on th... | Wikipedia - Vapor etching - XeF2 vapor etching > Etch chemistry | 275 | 865 | null |
Article: Wind turbine. A wind turbine is a device that converts the kinetic energy of wind into electrical energy. As of 2020, hundreds of thousands of large turbines, in installations known as wind farms, were generating over 650 gigawatts of power, with 60 GW added each year. Wind turbines are an increasingly importa... | Wikipedia - Wind turbine - Summary | 204 | 1,088 | null |
Section: History. The windwheel of Hero of Alexandria (10–70 CE) marks one of the first recorded instances of wind powering a machine. However, the first known practical wind power plants were built in Sistan, an Eastern province of Persia (now Iran), from the 7th century. These "Panemone" were vertical axle windmills,... | Wikipedia - Wind turbine - History | 343 | 1,609 | null |
The batteries powered various electrical tools and lamps, as well as a threshing machine. Friedländer's windmill and its accessories were prominently installed at the north entrance to the main exhibition hall ("Rotunde") in the Vienna Prater. In July 1887, Scottish academic James Blyth installed a battery-charging mac... | Wikipedia - Wind turbine - History | 330 | 1,596 | null |
A forerunner of modern horizontal-axis wind generators was in service at Yalta, USSR, in 1931. This was a 100 kW generator on a 30-meter (98 ft) tower, connected to the local 6.3 kV distribution system. It was reported to have an annual capacity factor of 32 percent, not much different from current wind machines. In th... | Wikipedia - Wind turbine - History | 342 | 1,721 | null |
Section: Efficiency. Conservation of mass requires that the mass of air entering and exiting a turbine must be equal. Likewise, the conservation of energy requires the energy given to the turbine from incoming wind to be equal to that of the combination of the energy in the outgoing wind and the energy converted to ele... | Wikipedia - Wind turbine - Efficiency | 343 | 1,406 | null |
Further inefficiencies, such as gearbox, generator, and converter losses, reduce the power delivered by a wind turbine. To protect components from undue wear, extracted power is held constant above the rated operating speed as theoretical power increases as the cube of wind speed, further reducing theoretical efficienc... | Wikipedia - Wind turbine - Efficiency | 330 | 1,692 | null |
In an Ege University experiment, three wind turbines, each with three blades with a diameter of one meter, were constructed with blades made of different materials: A glass and glass/carbon epoxy, glass/carbon, and glass/polyester. When tested, the results showed that the materials with higher overall masses had a grea... | Wikipedia - Wind turbine - Efficiency | 161 | 830 | null |
Section: Types > Horizontal axis. Large three-bladed horizontal-axis wind turbines (HAWT) with the blades upwind of the tower (i.e. blades facing the incoming wind) produce the overwhelming majority of wind power in the world today. These turbines have the main rotor shaft and electrical generator at the top of a tower... | Wikipedia - Wind turbine - Types > Horizontal axis | 328 | 1,714 | null |
In high winds, downwind blades can also be designed to bend more than upwind ones, which reduces their swept area and thus their wind resistance, mitigating risk during gales. Despite these advantages, upwind designs are preferred, because the pulsing change in loading from the wind as each blade passes behind the supp... | Wikipedia - Wind turbine - Types > Horizontal axis | 217 | 1,044 | null |
Section: Types > Vertical axis. Vertical-axis wind turbines (or VAWTs) have the main rotor shaft arranged vertically. One advantage of this arrangement is that the turbine does not need to be pointed into the wind to be effective, which is an advantage on a site where the wind direction is highly variable. It is also a... | Wikipedia - Wind turbine - Types > Vertical axis | 345 | 1,829 | null |
Section: Design and construction > Components. Wind turbines convert wind energy to electrical energy for distribution. Conventional horizontal axis turbines can be divided into three components: The rotor, which is approximately 20% of the wind turbine cost, includes the blades for converting wind energy to low-speed ... | Wikipedia - Wind turbine - Design and construction > Components | 224 | 1,111 | null |
Section: Technology > Blade materials > Glass and carbon fibers. The stiffness of composites is determined by the stiffness of fibers and their volume content. Typically, E-glass fibers are used as main reinforcement in the composites. Typically, the glass/epoxy composites for wind turbine blades contain up to 75% glas... | Wikipedia - Wind turbine - Technology > Blade materials > Glass and carbon fibers | 216 | 973 | null |
Section: Technology > Costs. As of 2019, the capital cost of a wind turbine was around $1 million per megawatt of nameplate capacity, though this figure varies by location; for example, such numbers ranged from a half million in South America to $1.7 million in Asia. For the wind turbine blades, while the material cost... | Wikipedia - Wind turbine - Technology > Costs | 157 | 771 | null |
Section: Technology > Non-blade materials. Wind turbine parts other than the rotor blades (including the rotor hub, gearbox, frame, and tower) are largely made of steel. Smaller turbines (as well as megawatt-scale Enercon turbines) have begun using aluminum alloys for these components to make turbines lighter and more ... | Wikipedia - Wind turbine - Technology > Non-blade materials | 175 | 894 | null |
Section: Technology > Material supply. A 2015 study of the material consumption trends and requirements for wind energy in Europe found that bigger turbines have a higher consumption of precious metals but lower material input per kW generated. The material consumption and stock at that time was compared to input mater... | Wikipedia - Wind turbine - Technology > Material supply | 324 | 1,641 | null |
Between 110,000 and 115,000 metric tons of fiber glass would be required per year, a 14% increase. Rare-earth metal use would not increase much compared to available supply, however rare-earth metals that are also used for other technologies such as batteries which are increasing its global demand need to be taken into... | Wikipedia - Wind turbine - Technology > Material supply | 343 | 1,609 | null |
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