Doesn't all this gassing stuff happen every time a chip gets hot, the cools off? What's different?
Mike At 04:04 PM 6/3/98 -0700, Douglas Mckean wrote: >Well, > >Just for my two cents, 40,000 ft equates to roughly 1/5 the pressure at >sea level or almost 3 lbs/in^2 absolute compared against 14.7 lbs/in^2 >at sea level absolute. That leaves any type of plug or wall structure >of the capacitor having to withstand 11 lbs/in^2 across it. > >Also, the capacitor or even a transformer may have fluid inside and >leak. > >It also may involve a chip ingassing humidity once it's back on the >ground. >Why? Assume typical temp at 40,000 ft is nominally -70 degrees F. >Within >a matter of minutes the plane could be on the ground in some tropical >area. Condensation occurs on the chip, water forms, ingassing occurs >and now you've got a saturated chip. > >Regards, Doug > >[email protected] wrote: >> >> There is also an FAA? limit on the magnetic properties of air >> shipments. The gauss from the package must be within a stated >> maximum to avoid interference with navigational instrumentation. >> Even a concentrated shipment of small motors can exceed the >> limit due to the magnetized elements within. >> >> It has been five years since I was in EMC so I can't cite the >> actual standard or regulation. >> >> Don't know if this is what you were looking for...... >> >> George Alspaugh >> Product Safety >> >> Please respond to rbusche%[email protected] >> >> To: emc-pstc%[email protected] >> cc: (bcc: George Alspaugh) >> bcc: George Alspaugh >> Subject: Altitude >> >> This is not a safety or EMI question, but because this group has such >> broad backgrounds and diversity I am hoping that someone can comment. >> >> I have been asked by one of our customers to ensure that our equipment >> is capable of being shipped in an un-pressurized aircraft for altitudes >> of 30K to 40 K feet. This is a non operational requirement, but are >> there other concerns I should be aware of? I recall hearing that some >> commercial grade electrolytic could explode at high altitudes. >> >> Any comments or suggestions greatly appreciated. >> >> Rick Busche >> Evans & Sutherland >> Salt Lake City, Utah >> [email protected] > >
