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| Laminated launch loop rotors will have good magnetic properties and will rapidly disperse and oxidize in the atmosphere after a rotor-release catastrophe. | Laminated launch loop rotors will have good magnetic properties and will rapidly disperse and oxidize in the atmosphere after a rotor-release catastrophe. Worst case, thin flakes survive and cut. |
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| . [[ http://metglas.com/products/magnetic_materials/2605SA1.asp | Metglas 2605SA1 ]] looks good, higher temperature than 2605HB1M. . [[ attachment:2605sa1.pdf | datasheet ]] downloaded 2017/02/11 |
[[ http://metglas.com/products/magnetic_materials/2605SA1.asp | Metglas 2605SA1 ]] looks good, higher temperature than 2605HB1M. [[ attachment:2605sa1.pdf | datasheet ]] downloaded 2017/02/11 |
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| ||<-2:> '''Metglas 2605SA1''' || || Curie temperature || 395C / 668K || || saturation induction || 1.56 Tesla || || resistivity || 1.3 μΩ-m || || thickness || 23 μm || || density || 7.18 g/m³ || || Tensile Strength || 1 GPa || || Elastic Modulus || 100 GPa || || Thermal Expansion || 7.6 ppm/°C || || Iron || 85 to 95% || || Silicon || 5 to 10% || || Boron || 1 to 5% || ||<-2> 60 Hz and 1.4 T || || Induction at 80 A/m || ≥1.35 T || || Core Loss || ≤0.17 W/kg || ||Exciting Apparent Power* || 1.1 (VA/kg) || |
||<-5:> '''Metglas 2605SA1''' || || Curie temperature || 395C / 668K || || saturation induction || 1.56 Tesla || || thickness || 23 μm || || density || 7.18 g/cm³ || || Thermal Expansion || 7.6 ppm/°C || || Iron vaporization temp || 3140 K || || Tensile Strength || 1 GPa || || Elastic Modulus || 100 GPa || || Iron || 85 to 95% || || [[ https://www.cdc.gov/niosh/npg/npgd0344.html | IDLH Fe₂O₃]] || 2.5g/m³ || || Silicon || 5 to 10% || || [[ https://www.cdc.gov/niosh/npg/npgd0552.html | IDLH SiO₂]] || 3.0g/m³ || || Boron || 1 to 5% || || [[ https://www.cdc.gov/niosh/idlh/1303862.html | IDLH B₂O₃]] || 2,0g/m³ || || resistivity || 1.3 μΩ-m || ||<-2> || ||<-2> 60 Hz and 1.4 T || || Induction at 80 A/m || ≥1.35 T || || Core Loss || ≤0.17 W/kg || ||Exciting Apparent Power* || 1.1 (VA/kg) || |
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| The core loss appears proportional to (frequency × flux )² . | || [[attachment:2605SA1_coreloss.jpg | {{attachment:2605SA1_coreloss.jpg}}]] || Core loss appears proportional <<BR>>to (frequency × flux )^1.8^ .<<BR>><<BR>> Figure from datasheet. || Naively, assume that the rotor is excited at 100 KHz and produces 150 KN of thrust against a payload moving at a relative speed of 3 km/s with a wavelength of 0.1 m, an excitation frequency of 30 KHz. Assume a similar synchronous frequency (it will actually be slightly lower). Assume a sled length of 100 meters. || force on payload || 150 KN || || payload speed || 11 km/s || || track coil pitch || 0.11 m || || track field frequency || 100 KHz || || rotor speed || 14 km/s || || rotor coil pitch || || || rotor field frequency || || |
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| == Failure and oxidation == Iron has a specific heat of 25.1 J/(mol·K), vaporizes at 3140K, and has a heat of vaporization of 340 kJ/mol . Naively, to go from 400K to vaporization requires 410 kJ/mol or 16 MJ/kg . The rotor moves at 14 km/s, the kinetic energy is 98 MJ/kg, so there is more than enough energy to vaporize the rotor foil and ignite it. '''Further study and experimentation needed'''; perhaps most of the energy will end up heating the surrounding air, and the foil will fragment and fall to the ocean surface and then the sea floor. |
Rotor Lamination
Laminated launch loop rotors will have good magnetic properties and will rapidly disperse and oxidize in the atmosphere after a rotor-release catastrophe. Worst case, thin flakes survive and cut.
Metglas 2605SA1 looks good, higher temperature than 2605HB1M. datasheet downloaded 2017/02/11
Metglas 2605SA1 |
||||
Curie temperature |
395C / 668K |
|
saturation induction |
1.56 Tesla |
thickness |
23 μm |
|
density |
7.18 g/cm³ |
Thermal Expansion |
7.6 ppm/°C |
|
Iron vaporization temp |
3140 K |
Tensile Strength |
1 GPa |
|
Elastic Modulus |
100 GPa |
Iron |
85 to 95% |
|
2.5g/m³ |
|
Silicon |
5 to 10% |
|
3.0g/m³ |
|
Boron |
1 to 5% |
|
2,0g/m³ |
|
resistivity |
1.3 μΩ-m |
|
|
|
60 Hz and 1.4 T |
|
Induction at 80 A/m |
≥1.35 T |
|
Core Loss |
≤0.17 W/kg |
|
Exciting Apparent Power* |
1.1 (VA/kg) |
|
Core loss appears proportional |
Naively, assume that the rotor is excited at 100 KHz and produces 150 KN of thrust against a payload moving at a relative speed of 3 km/s with a wavelength of 0.1 m, an excitation frequency of 30 KHz. Assume a similar synchronous frequency (it will actually be slightly lower). Assume a sled length of 100 meters.
force on payload |
150 KN |
payload speed |
11 km/s |
track coil pitch |
0.11 m |
track field frequency |
100 KHz |
rotor speed |
14 km/s |
rotor coil pitch |
|
rotor field frequency |
|
Failure and oxidation
Iron has a specific heat of 25.1 J/(mol·K), vaporizes at 3140K, and has a heat of vaporization of 340 kJ/mol . Naively, to go from 400K to vaporization requires 410 kJ/mol or 16 MJ/kg . The rotor moves at 14 km/s, the kinetic energy is 98 MJ/kg, so there is more than enough energy to vaporize the rotor foil and ignite it. Further study and experimentation needed; perhaps most of the energy will end up heating the surrounding air, and the foil will fragment and fall to the ocean surface and then the sea floor.