SPECIAL PURPOSE MACHINES D.VENKATESH G.MADAN L6EE924 Y5EE840 EMAIL: [email protected] EMAIL:[email protected] Phone: 9963510494 Phone: 9963510494 R.V.R & J.C.COLLEGE OF ENGINEERING Chandramoulipuram Chowdavram GUNTUR - 19 ABSTRACT: Day by day the interest on Nano generator special machines increases. Because Researchers have these machines serves for several demonstrated a prototype nanometer- applications.For instance,the nano scale generator that produces continuous generator could drive biological sensors direct-current electricity by harvesting by making use of wind energy or water mechanical energy from such flow,eliminating the need for external environmental sources as ultrasonic batteries.This not only reduces the waves, mechanical vibration or blood device cost but also at the same time flow. The nanogenerators take advantage reduces the entire equipment size. of the unique coupled piezoelectric and Integrated starter generator semiconducting properties of zinc oxide which is used in electric vehicles acts as nanostructures, which produce small a bidirectional energy converter as a electrical charges. motor when powered by the battery or a generator when driven by the engine.Linear motors are used to propel high speed MagLev trains.Micro motors plays an important role in computer hard drives,optics,sensors and actuators.A special type of outer rotor motors used to drive the polygonal rotating mirrors which are mounted directly on the rotor in laser printers. Our paper tries to introduce some of these machines and their applications in various fields.The recent developed technology of nano Fabrication begins with growing an generators is included and its working is array of vertically-aligned nanowires also explained. approximately a half-micron apart on 2 gallium arsenide, sapphire or a flexible Nano motor polymer substrate. A layer of zinc oxide is grown on top of substrate to collect Even smaller motors the current. The researchers also have been made using nanotechnology. fabricate silicon “zig-zag” electrodes, An example is shown below. It consists which contain thousands of nanometer- of a tiny gold slab rotor, about 100 nm scale tips made conductive by a platinum square, mounted on concentric carbon coating. nanotubes.The outer tube carries the rotor, driven by electrostatic electrodes, The electrode is then lowered rotating around an inner tube which acts on top of the nanowire array, leaving just as a supporting shaft. By applying enough space so that a significant voltage pulses of up to 5 Volts between number of the nanowires are free to flex the rotor plate and stators, the position, within the gaps created by the tips. speed and direction of rotation of the Moved by mechanical energy such as rotor can be controlled. It measures waves or vibration, the nanowires about 500 nanometers across, 300 times periodically contact the tips, transferring smaller than the diameter of a human their electrical charges. By capturing the hair. tiny amounts of current produced by hundreds of nanowires kept in motion, the generators produce a direct current output in the nano-Ampererange. If we had a device like this in our shoes when we walked, we would be able to generate our own small current to power small electronics.Anything that makes the nanowires move within the generator The motor was built from can be used for generating power. Very multiwalled nanotubes created in an little force is required to move them. electric arc and deposited on the flat silicon oxide surface of a silicon wafer. A rotor, nanotube anchors and opposing 3 stators were then simultaneously shaped glass fibre circuit board which patterned in gold around the selected rotates in the air gap between pairs of nanotubes using electron beam permanent magnets arranged around the lithography. A third stator was already periphery of the disk. The windings fan buried under the silicon oxide surface. out in a series of radial loops around the The silicon was then etched to create a surface of the disk. The magnets are trough beneath the rotor with sufficient arranged alternatively north and south so clearance for the rotor to rotate.Possible that the magnetic fields in the air gaps of applications are moveable mirrors for adjacent magnet pairs are in opposite optical switches or paddles for moving directions. The magnets are held in place fluids. by two iron end caps in a compact "pancake" shaped block to complete the Axial Field Motors magnetic circuit. Current is fed to the rotor windings via brushes through Axial field motors precious metal commutator segments have been developed for applications printed on the disc. which require short, flat, "pancake" construction. Printed Circuit (PCB) or "Pancake" Motor: The printed circuit motor is an example of an ironless or coreless motor with several unique features. The pancake construction uses an axial magnetic field to achieve the short flat construction. Radial field PCB Operating Principle: motors are also possible. Traditional electric motors Construction: have a radial magnetic field or flux with The rotor windings are printed, the rotor current flowing axially along stamped or welded onto a thin, disc the length of the rotor. In typical printed 4 circuit motors the construction is Since the rotor does not have drag a reversed. The magnetic field is axial lump of iron around, it has very low (oriented along the axis of the machine) inertia and can run up to speed very and the current flows radially from the quickly. Because of the many axis to the edge of the disc and back commutator segments and the low again. A tangential force on the disk is current capability of the windings, the created by the current passing through PCB motor is only suitable for low the magnetic fields in the air gaps power applications and is not suitable for between the pole pairs of the permanent continuous operation. It is however ideal magnets. So that the return current does for servo systems and industrial controls not cancel out the effect of the outgoing and automotive applications such as current, the return wire is physically electric window winders. separated or displaced to one side from the outgoing wire by the width of the Outer Rotor Motors magnet. In this way it interacts with the magnetic field of the adjacent magnet There are many designs using which is in the opposite direction and this construction, mostly for small sizes. thus reinforces the tangential force on Two examples of low power motors are the disk. shown below. High power versions are used for "in wheel" automotive In many ways it is similar applications. to Faraday's 1831disk or homopolar motor which used a single magnet and Inside Out Motor was driven by a unidirectional current These are permanent fed by brushes at the centre and on the magnet motors with the moving magnets periphery of the disk. arranged around the periphery of a multi pole fixed stator carrying the field Applications : windings. The printed circuit motor is a very compact and light weight design making it useful in confined spaces. 5 Because of the low inertia and friction free rotor, the toroidal motor is capable of speeds up to 25,000 RPM. Suitable for low power applications it is used for example to drive the polygonal rotating mirrors which are mounted directly on the rotor in laser printers. Integrated starter Used for automotive generator(ISG): drive systems including in-wheel motors. Low power versions used in small cooling fans and direct drive The electronically controlled record. integrated starter generator used in mild hybrid electric vehicles (HEVs) Toroidal Coil Motor combines the automotive starter and alternator into a single machine. This is an "inside out" brushless permanent magnet motor with a toroidal wound stator covered by a cup shaped permanent magnet outer rotor. "Design of a Switched Reluctance Machine for Extended Speed Operation" 6 The conventional starter is a low speed, The system voltage in a mild HEV is 42 high current DC machine, while the Volts which means that, for the same alternator is a variable speed 3 phase ac cranking power as a 12 Volt machine, machine. the starter current can be reduced. The ISG has four important functions in Typical power throughput is between a hybrid vehicle application 5kW and 15 kW with a possible peak power of 70 kW for cold cranking. • It enables the "start-stop" The brushless function, turning off the engine when the ISG design eliminates one rotating vehicle is stationary saving fuel. machine completely as well as the • It generates the electrical energy associated commutator and brushes from to power all the electrical ancillaries. the DC machine and the sliprings and • It provides a power boost to brushes from the AC machine. The assist the engine when required, starter solenoid, the Bendix ring (starter permitting smaller engines for gear) and the pulley or gear drive to the similar performance. alternator are also no longer needed and • In some configurations it because of the higher system voltage, the recuperates energy from regenerative diameter and weight of the copper braking. cabling is also reduced substantially. The savings however come at a cost. The In a typical system must be integrated with several implementation (below), the ISG is a subsystems as follows short axis, large diameter "pancake" shaped switched reluctance machine • An AC/DC converter to rectify mounted directly on the end of the the generator output voltage. engine crankshaft between the engine • A DC/DC converter to supply the and the clutch in the gearbox bell vehicle's electrical power system housing.The ISG is a bi-directional voltages. energy converter acting as a motor when • Power electronics and software powered by the battery or a generator to control the ISG current, voltage, when driven by the engine.