31-01-2010, 02:51 PM
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31-01-2010, 02:51 PM
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31-01-2010, 07:41 PM
Abstract:
Electrodynamic tethers are long conducting wires which is used to power satellite , the one deployed from the tether satellite, The gravity gradient field (also known as the "tidal force") will tend to orient the tether in a vertical position. If the tether is orbiting around the Earth, it will be crossing the Earth's magnetic field lines at orbital velocity (7-8 km/s!). The motion of the conductor across the magnetic field induces a voltage along the length of the tether. This voltage can be up to several hundred volts per kilometer.which is based on electromagnetic principles as generators, by converting their kinetic energy to electrical energy, An EDT takes advantage of two basic principles of electromagnetism: current is produced when a conductive wire moves through a magnetic field, and the field exerts a force on the current, or as motors, converting electrical energy to kinetic energy. Electric potential is generated across a conductive tether by its motion through the Earth's magnetic field. The choice of the metal conductor to be used in an electrodynamic tether is determined by a variety of factors. Such as high electrical conductivity, and low density. Secondary factors, depending on the application, include cost, strength, and melting point. An EDT system is made up of two masses in orbit connected by a long, flexible, electrically conductive cable; the tether is essentially a wire that moves through the magnetic field of the Earth (or another planet or large body) please read http://www.highfrontierArchive/Jt/Tether...804050.pdf http://en.wikipediawiki/Electrodynamic_tether http://www.spacebusinesstechnology/techn...41109.html
21-02-2010, 12:45 PM
please read https://seminarproject.net/Thread-electr...ull-report for getting full report of Electro Dynamic Tether
03-02-2011, 10:58 AM
is there a ppt for this report ?
25-02-2012, 09:14 PM
can u send me the ppt for electrodynamic tether seminar topic
15-06-2012, 11:29 AM
Electro dynamic tether
Electrodynamic tether.docx (Size: 924.24 KB / Downloads: 37) Tether propulsion Main article: Tether propulsion As part of a tether propulsion system, crafts can use long, strong conductors (though not all tethers are conductive) to change the orbits of spacecraft. It has the potential to make space travel significantly cheaper. It is a simplified, very low-budget magnetic sail. It can be used either to accelerate or brake an orbiting spacecraft. When direct current is pumped through the tether, it exerts a Lorentz force against the magnetic field, and the tether accelerates the spacecraft. Uses for ED Tethers Over the years, numerous applications for electrodynamic tethers have been identified for potential use in industry, government, and scientific exploration. The table below is a summary of some of the potential applications proposed thus far. Some of these applications are general concepts, while others are well-defined systems. Many of these concepts overlap into other areas; however, they are simply placed under the most appropriate heading for the purposes of this table. All of the applications mentioned in the table are elaborated upon in the Tethers Handbook.[1] Three fundamental concepts that tethers possess, that will be discussed within this thesis are gravity gradients, momentum exchange, and electrodynamics. Kirchoff’s Voltage Law Since the current is continuously changing along the bare length of the tether, the potential loss due to the resistive nature of the wire is represented as . Along an infinitesimal section of tether, the resistance ‘dRt’ multiplied by the current traveling across that section ‘I(y)’ calculates the resistive potential loss. After evaluating KVL & KCL (above 2 equations) for the system, the results will yield a current and potential profile along the tether, as seen in above figure. This diagram shows that, from point A of the tether down to point B, there is a positive potential bias, which increases the collected current. Below that point, the V − Vp becomes negative and the collection of ion current begins. Since it takes a much greater potential difference to collect an equivalent amount of ion current (for a given area), the total current in the tether is reduced by a smaller amount. Then, at point C, the remaining current in the system is drawn through the resistive load (Rload), and emitted from an electron emissive device (Vemit), and finally across the plasma sheath (Vcathode). The KVL voltage loop is then closed in the ionosphere where the potential difference is effectively zero. Voltage and current NASA has conducted several experiments with Plasma Motor Generator (PMG) tethers in space. An early experiment used a 500 meter conducting tether. In 1996, NASA conducted an experiment with a 20,000-meter conducting tether. When the tether was fully deployed during this test, the orbiting tether generated a potential of 3,500 volts. This conducting single-line tether was severed after five hours of deployment. It is believed that the failure was caused by an electric arc generated by the conductive tether's movement through the Earth's magnetic field.[9] |
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