eol.jsc.nasa.gov/ForFun/HDEV/
Thursday, November 27, 2014
Saturday, November 8, 2014
AC Generator frequency as a function of RPM
w - angular velocity.
f - frequency (number of cycles per second, expressed in Hz).
P - number of poles (= N + S poles. ).
P/2 - number of pole pairs. Above generator example has two poles and one pole pair.
Ns - number of revolutions per second
Nm - number of revolutions per minute
Nm=60*Ns.
w=2Pi*f = (P/2) * N * 2Pi * 1/sec
f=(P/2)*N/sec
f=(P/2)*Ns
f=(P/2)*Nm/60=P*N/120
f=P*Nm/120
Monday, November 3, 2014
Neodymium Magnet Physical Properties
(source: http://www.monroeengineering.com/NeodymiumMagnetPhysicalProperties.html)
Magnetic Characteristics
Material Type Residual Flux Density
(Br) Coercive Force
(Hc) Intrinsic Coercive Force (Hci) Max.Energy Product
(BH)max N35 11.7-12.1 KGs >11.0 KOe >12 KOe 33-35 MGOe N38 12.2-12.6 KGs >11.0 KOe >12 KOe 36-38 MGOe N40 12.6-12.9 KGs >11.0 KOe >12 KOe 38-40 MGOe N42 13.0-13.2 KGs >11.0 KOe >12 KOe 40-42 MGOe N45 13.3-13.7 KGs >11.0 KOe >12 KOe 43-45 MGOe N48 13.8-14.2 KGs >11.0 KOe >12 KOe 45-48 MGOe N50 14.1-14.5 KGs >11.0 KOe >11 KOe 48-50 MGOe N52 14.5-14.8 KGs >11.2 KOe >11 KOe 49.5-52 MGOe N35M 11.7-12.1 KGs >11.4 KOe >14 KOe 33-35 MGOe N38M 12.2-12.6 KGs >11.4 KOe >14 KOe 36-38 MGOe N40M 12.6-12.9 KGs >11.4 KOe >14 KOe 38-40 MGOe N42M 13.0-13.3 KGs >11.4 KOe >14 KOe 40-42 MGOe N45M 13.3-13.7 KGs >11.4 KOe >14 KOe 42-45 MGOe N48M 13.6-14.2 KGs >11.4 KOe >14 KOe 45-48 MGOe N50M 14.1-14.5 KGs >11.4 KOe >14 KOe 48-50 MGOe N33H 11.4-11.7 KGs >10.3 KOe >17 KOe 31-33 MGOe N35H 11.7-12.1 KGs >10.8 KOe >17 KOe 33-35 MGOe N38H 12.2-12.6 KGs >11.4 KOe >17 KOe 36-38 MGOe N40H 12.6-12.9 KGs >11.4 KOe >17 KOe 38-40 MGOe N42H 13.0-13.3 KGs >11.4 KOe >17 KOe 40-42 MGOe N45H 13.3-13.7 KGs >11.4 KOe >17 KOe 42-45 MGOe N48H 13.6-14.2 KGs >11.4 KOe >16 KOe 45-48 MGOe N30SH 10.8-11.2 KGs >10.1 KOe >20 KOe 28-30 MGOe N33SH 11.4-11.7 KGs >10.3 KOe >20 KOe 31-33 MGOe N35SH 11.7-12.1 KGs >10.8 KOe >20 KOe 33-35 MGOe N38SH 12.2-12.6 KGs >11.4 KOe >20 KOe 36-38 MGOe N40SH 12.6-12.9 KGs >11.4 KOe >20 KOe 38-40 MGOe N42SH 13.0-13.3 KGs >11.4 KOe >20 KOe 40-42 MGOe N45SH 13.3-13.7 KGs >11.4 KOe >19 KOe 43-45 MGOe N28UH 10.4-10.8 KGs >9.8 KOe >25 KOe 26-28 MGOe N30UH 10.8-11.2 KGs >10.1 KOe >25 KOe 28-30 MGOe N33UH 11.4-11.7 KGs >10.3 KOe >25 KOe 31-33 MGOe N35UH 11.7-12.1 KGs >10.8 KOe >25 KOe 33-35 MGOe N38UH 12.2-12.6 KGs >11.4 KOe >25 KOe 36-38 MGOe N40UH 12.6-12.9 KGs >11.4 KOe >25 KOe 38-40 MGOe N28EH 10.4-10.8 KGs >9.8 KOe >30 KOe 26-28 MGOe N30EH 10.8-11.2 KGs >10.1 KOe >30 KOe 28-30 MGOe N33EH 11.4-11.7 KGs >10.3 KOe >30 KOe 31-33 MGOe N35EH 11.7-12.1 KGs >10.8 KOe >30 KOe 33-35 MGOe N38EH 12.2-12.6 KGs >10.8 KOe >30 KOe 36-38 MGOe
Thermal Characteristics
Neodymium Material Type Thermal Expansion Coeff. Maximum Operating Temp Curie Temp Thermal Conductivity %/¡ÆC ¡ÆC (¡ÆF) ¡ÆC (¡ÆF) kcal/m-h-¡ÆC N -0.12 176¡ÆF (80¡ÆC) 590¡ÆF (310¡ÆC) 7.7 NM -0.12 212¡ÆF (100¡ÆC) 644¡ÆF (340¡ÆC) 7.7 NH -0.11 248¡ÆF (120¡ÆC) 644¡ÆF (340¡ÆC) 7.7 NSH -0.10 302¡ÆF (150¡ÆC) 644¡ÆF (340¡ÆC) 7.7 NUH -0.10 356¡ÆF (180¡ÆC) 662¡ÆF (350¡ÆC) 7.7 NEH -0.10 392¡ÆF (200¡ÆC) 662¡ÆF (350¡ÆC) 7.7
The Thermal Characteristics listed above are values commonly associated with each magnet's grade or material. Actual performance in your application may vary with other factors, including the shape of the magnet, the Permeance Coefficient or load line, and how it is used in a circuit.
Physical and Mechanical Characteristics
Density
7.4-7.5 g/cm3
Compression Strength
110 kg/mm2
Bending Strength
25 kg/mm2
Vickers Hardness (Hv)
560-600
Tensile Strength
7.5kg/mm2
Young's Modulus
1.7 x 104 kg/mm2
Recoil Permeability
1.05 ¥ìrec
Electrical Resistance (R)
160 ¥ì-ohm-cm Heat Capacity 350-500 J/(kg.¡ÆC) Thermal Expansion Coefficient (0 to 100¡ÆC)
parallel to magnetization direction 5.2 x 10-6 /¡ÆC Thermal Expansion Coefficient (0 to 100¡ÆC)
perpendicular to magnetization direction -0.8 x 10-6 /¡ÆC
Plating Characteristics
Plating Type Overall Thickness Salt Spray Test Pressure Cooker Test NiCuNi (Nickel Copper Nickel) 15-21 ¥ìm 24 hours 48 hours NiCu + Black Nickel 15-21 ¥ìm 24 hours 48 hours NiCuNi + Epoxy 20-28 ¥ìm 48 hours 72 hours NiCuNi + Gold 16-23 ¥ìm 36 hours 72 hours NiCuNi + Silver 16-23 ¥ìm 24 hours 48 hours Zinc 7-15 ¥ìm 12 hours 24 hours
Each individual layer of Nickel and Copper are 5-7 ¥ìm thick. The Gold and Silver plating layers are 1-2 ¥ìm thick.
Test results shown to allow comparison between plating options. Performance in your application under your specific test conditions may vary. Salt Spray testing conducted with a 5% NaCl solution, at 35¡ÆC. Pressure Cooker Test (PCT) conducted at 2 atm, 120¡ÆC at 100% RH.
Measurement Systems
Unit cgs System SI System English System Length (L) centimeter (cm) meter (m) inch (in) Flux (©ª) Maxwell Weber (Wb) Maxwell Flux Density (B) Gauss (G) Tesla (T) lines/in2 Magnetizing Force (H) Oersted (Oe) Ampere turns/m (At/m) Ampere turns/in (At/in) Magnetomotive Force (mmf or F) Gilbert (Gb) Ampere turn (At) Ampere turn (At)
Conversion Between Systems
cgs System to SI system 1 Oe = 79.62 At/m 10,000 G = 1 T 1 Gb = 0.79577 At 1 Maxwell = 1 Line = 10-8 Wb 1 G = 0.155 lines/in2
| Material Type | Residual Flux Density (Br) | Coercive Force (Hc) | Intrinsic Coercive Force (Hci) | Max.Energy Product (BH)max |
| N35 | 11.7-12.1 KGs | >11.0 KOe | >12 KOe | 33-35 MGOe |
| N38 | 12.2-12.6 KGs | >11.0 KOe | >12 KOe | 36-38 MGOe |
| N40 | 12.6-12.9 KGs | >11.0 KOe | >12 KOe | 38-40 MGOe |
| N42 | 13.0-13.2 KGs | >11.0 KOe | >12 KOe | 40-42 MGOe |
| N45 | 13.3-13.7 KGs | >11.0 KOe | >12 KOe | 43-45 MGOe |
| N48 | 13.8-14.2 KGs | >11.0 KOe | >12 KOe | 45-48 MGOe |
| N50 | 14.1-14.5 KGs | >11.0 KOe | >11 KOe | 48-50 MGOe |
| N52 | 14.5-14.8 KGs | >11.2 KOe | >11 KOe | 49.5-52 MGOe |
| N35M | 11.7-12.1 KGs | >11.4 KOe | >14 KOe | 33-35 MGOe |
| N38M | 12.2-12.6 KGs | >11.4 KOe | >14 KOe | 36-38 MGOe |
| N40M | 12.6-12.9 KGs | >11.4 KOe | >14 KOe | 38-40 MGOe |
| N42M | 13.0-13.3 KGs | >11.4 KOe | >14 KOe | 40-42 MGOe |
| N45M | 13.3-13.7 KGs | >11.4 KOe | >14 KOe | 42-45 MGOe |
| N48M | 13.6-14.2 KGs | >11.4 KOe | >14 KOe | 45-48 MGOe |
| N50M | 14.1-14.5 KGs | >11.4 KOe | >14 KOe | 48-50 MGOe |
| N33H | 11.4-11.7 KGs | >10.3 KOe | >17 KOe | 31-33 MGOe |
| N35H | 11.7-12.1 KGs | >10.8 KOe | >17 KOe | 33-35 MGOe |
| N38H | 12.2-12.6 KGs | >11.4 KOe | >17 KOe | 36-38 MGOe |
| N40H | 12.6-12.9 KGs | >11.4 KOe | >17 KOe | 38-40 MGOe |
| N42H | 13.0-13.3 KGs | >11.4 KOe | >17 KOe | 40-42 MGOe |
| N45H | 13.3-13.7 KGs | >11.4 KOe | >17 KOe | 42-45 MGOe |
| N48H | 13.6-14.2 KGs | >11.4 KOe | >16 KOe | 45-48 MGOe |
| N30SH | 10.8-11.2 KGs | >10.1 KOe | >20 KOe | 28-30 MGOe |
| N33SH | 11.4-11.7 KGs | >10.3 KOe | >20 KOe | 31-33 MGOe |
| N35SH | 11.7-12.1 KGs | >10.8 KOe | >20 KOe | 33-35 MGOe |
| N38SH | 12.2-12.6 KGs | >11.4 KOe | >20 KOe | 36-38 MGOe |
| N40SH | 12.6-12.9 KGs | >11.4 KOe | >20 KOe | 38-40 MGOe |
| N42SH | 13.0-13.3 KGs | >11.4 KOe | >20 KOe | 40-42 MGOe |
| N45SH | 13.3-13.7 KGs | >11.4 KOe | >19 KOe | 43-45 MGOe |
| N28UH | 10.4-10.8 KGs | >9.8 KOe | >25 KOe | 26-28 MGOe |
| N30UH | 10.8-11.2 KGs | >10.1 KOe | >25 KOe | 28-30 MGOe |
| N33UH | 11.4-11.7 KGs | >10.3 KOe | >25 KOe | 31-33 MGOe |
| N35UH | 11.7-12.1 KGs | >10.8 KOe | >25 KOe | 33-35 MGOe |
| N38UH | 12.2-12.6 KGs | >11.4 KOe | >25 KOe | 36-38 MGOe |
| N40UH | 12.6-12.9 KGs | >11.4 KOe | >25 KOe | 38-40 MGOe |
| N28EH | 10.4-10.8 KGs | >9.8 KOe | >30 KOe | 26-28 MGOe |
| N30EH | 10.8-11.2 KGs | >10.1 KOe | >30 KOe | 28-30 MGOe |
| N33EH | 11.4-11.7 KGs | >10.3 KOe | >30 KOe | 31-33 MGOe |
| N35EH | 11.7-12.1 KGs | >10.8 KOe | >30 KOe | 33-35 MGOe |
| N38EH | 12.2-12.6 KGs | >10.8 KOe | >30 KOe | 36-38 MGOe |
Thermal Characteristics
| Neodymium Material Type | Thermal Expansion Coeff. | Maximum Operating Temp | Curie Temp | Thermal Conductivity |
| %/¡ÆC | ¡ÆC (¡ÆF) | ¡ÆC (¡ÆF) | kcal/m-h-¡ÆC | |
| N | -0.12 | 176¡ÆF (80¡ÆC) | 590¡ÆF (310¡ÆC) | 7.7 |
| NM | -0.12 | 212¡ÆF (100¡ÆC) | 644¡ÆF (340¡ÆC) | 7.7 |
| NH | -0.11 | 248¡ÆF (120¡ÆC) | 644¡ÆF (340¡ÆC) | 7.7 |
| NSH | -0.10 | 302¡ÆF (150¡ÆC) | 644¡ÆF (340¡ÆC) | 7.7 |
| NUH | -0.10 | 356¡ÆF (180¡ÆC) | 662¡ÆF (350¡ÆC) | 7.7 |
| NEH | -0.10 | 392¡ÆF (200¡ÆC) | 662¡ÆF (350¡ÆC) | 7.7 |
Physical and Mechanical Characteristics
Density
| 7.4-7.5 g/cm3 |
Compression Strength
| 110 kg/mm2 |
Bending Strength
| 25 kg/mm2 |
Vickers Hardness (Hv)
| 560-600 |
Tensile Strength
| 7.5kg/mm2 |
Young's Modulus
| 1.7 x 104 kg/mm2 |
Recoil Permeability
| 1.05 ¥ìrec |
Electrical Resistance (R)
| 160 ¥ì-ohm-cm |
| Heat Capacity | 350-500 J/(kg.¡ÆC) |
| Thermal Expansion Coefficient (0 to 100¡ÆC) parallel to magnetization direction | 5.2 x 10-6 /¡ÆC |
| Thermal Expansion Coefficient (0 to 100¡ÆC) perpendicular to magnetization direction | -0.8 x 10-6 /¡ÆC |
| Plating Type | Overall Thickness | Salt Spray Test | Pressure Cooker Test |
| NiCuNi (Nickel Copper Nickel) | 15-21 ¥ìm | 24 hours | 48 hours |
| NiCu + Black Nickel | 15-21 ¥ìm | 24 hours | 48 hours |
| NiCuNi + Epoxy | 20-28 ¥ìm | 48 hours | 72 hours |
| NiCuNi + Gold | 16-23 ¥ìm | 36 hours | 72 hours |
| NiCuNi + Silver | 16-23 ¥ìm | 24 hours | 48 hours |
| Zinc | 7-15 ¥ìm | 12 hours | 24 hours |
Test results shown to allow comparison between plating options. Performance in your application under your specific test conditions may vary. Salt Spray testing conducted with a 5% NaCl solution, at 35¡ÆC. Pressure Cooker Test (PCT) conducted at 2 atm, 120¡ÆC at 100% RH.
Measurement Systems
| Unit | cgs System | SI System | English System |
| Length (L) | centimeter (cm) | meter (m) | inch (in) |
| Flux (©ª) | Maxwell | Weber (Wb) | Maxwell |
| Flux Density (B) | Gauss (G) | Tesla (T) | lines/in2 |
| Magnetizing Force (H) | Oersted (Oe) | Ampere turns/m (At/m) | Ampere turns/in (At/in) |
| Magnetomotive Force (mmf or F) | Gilbert (Gb) | Ampere turn (At) | Ampere turn (At) |
Conversion Between Systems
| cgs System to SI system |
| 1 Oe = 79.62 At/m |
| 10,000 G = 1 T |
| 1 Gb = 0.79577 At |
| 1 Maxwell = 1 Line = 10-8 Wb |
| 1 G = 0.155 lines/in2 |
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