----- Original Message -----
Sent: Friday, May 11, 2007 8:19 PM
Subject: [FlyRotary] Re: EC2
question
If you use them, derate well. For a 14V power source use at
least 25V parts, 50V would be better. The dielectric contains oxygen that
feeds the fire once it gets started. I work in the avionics business and we
aren't allowed to use them in new designs.
Geeze, Jim. Here I've been using tantalum
capacitors in my circuit boards. Are these failure modes spontaneous or
are they triggered by something like over voltage, over temp, etc. I
guess I'm a bit surprised at the violence of their demise - I would think
something like that would have curtailed their use in electronic
circuits.
Ed
----- Original Message -----
Sent: Friday, May 11, 2007 5:50 PM
Subject: [FlyRotary] Re: EC2 question
Al,
I would be very careful about adding any tantalum capacitors.
Back when I worked as an electronic technician I discovered the failure
mode of these devices.
They start off with a little leakage current.
As they leak the get hotter.
The hotter they get the more they leak.
This continues until they build to critical temp and then explode
sending a molten projectile 10 feet or more.
I actually had some blowup while testing and they burnt a hole in
the floor
10-20 feet away.
After that I always made sure that there was a
metal cover over the unit being tested.
Just a word to the wise.
Jim
Al Gietzen <ALVentures@cox.net> wrote:
SNIP
47uf, 16V tantalum were added to each processor
Pin 8 of
connector is now grounded.
Pin 28 of connector is now
grounded.
Al