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Size: 649
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← Revision 7 as of 2018-08-19 21:09:51 ⇥
Size: 1209
Comment:
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| Deletions are marked like this. | Additions are marked like this. |
| Line 6: | Line 6: |
| ---- | |
| Line 8: | Line 7: |
| . Tek 7000 series oscilloscopes used 25 KHz primary switcher | |
| Line 10: | Line 8: |
| . Aluminum resistivity from Physics Hypertextbook ValPolyakov.txt 2004 (missing linefeeds) | . Tektronix 7000 series oscilloscopes (designed in the 1970s) used 25 KHz switching power supplies . Aluminum resistivity from Physics Hypertextbook !ValPolyakov.txt 2004 (missing linefeeds) |
| Line 15: | Line 15: |
| || 300 || 2.7e-8 || 262 || 34 || 2.6 || 0.83 || || 400 || 3.9e-8 || 314 || 41 || 3.1 || 0.99 || |
|| 300 || 2.7e-8 || 262 || 34 || 2.6 || 0.83 || || 400 || 3.9e-8 || 314 || 41 || 3.1 || 0.99 || |
| Line 19: | Line 19: |
Reactive power supplies resistive drops in the rotor. Run capacitors on big induction motors supply less than a percent of total power to maintain 90 degrees out-of-phase currents in rotor windings. Aluminum specific heat is 910 J / Kg-K according to engineeringtoolbox.com (at what temperature???) According to [[ http://webbook.nist.gov/cgi/cbook.cgi?ID=C7429905&Mask=2&Type=JANAFS&Plot=on#JANAFS | this ]], specific heat increases from about 900 J/Kg-K at 298 C to 1300 J/Kg-K . The slope steepens near 300 K. |
Motor Track
Notes
- Tektronix 7000 series oscilloscopes (designed in the 1970s) used 25 KHz switching power supplies
Aluminum resistivity from Physics Hypertextbook ValPolyakov.txt 2004 (missing linefeeds)
Temp |
Resis |
Skin |
60 Hz |
10 KHz |
100 KHz |
K |
ohm m |
mm-√Hz |
mm |
mm |
mm |
200 |
1.6e-8 |
201 |
26 |
2.0 |
0.64 |
300 |
2.7e-8 |
262 |
34 |
2.6 |
0.83 |
400 |
3.9e-8 |
314 |
41 |
3.1 |
0.99 |
600 |
6.1e-8 |
393 |
51 |
3.9 |
1.24 |
800 |
8.7e-8 |
469 |
61 |
4.6 |
1.48 |
Reactive power supplies resistive drops in the rotor. Run capacitors on big induction motors supply less than a percent of total power to maintain 90 degrees out-of-phase currents in rotor windings.
Aluminum specific heat is 910 J / Kg-K according to engineeringtoolbox.com (at what temperature???)
According to this, specific heat increases from about 900 J/Kg-K at 298 C to 1300 J/Kg-K . The slope steepens near 300 K.