Dielectric strength

[M Gregg]

SY,

Dielectric strength,

How does this link to bonding of electrons within atomic structure?

Regards
M. Gregg

 

[M Gregg]

So here is the first question:

What happens to the bonding of the electrons as the material ages?
I notice that if you measure insulation resistance value over a period "Years" the value will drop until flash over takes place.

Regards
M.Gregg

 

[M Gregg]

For anyone interested:

http://en.wikipedia.org/wiki/Insulator_(electrical)

Just gives some background might be of interest.

Regards
M. Gregg

 

[SY]

If you're reading Wikipedia, look at this:

Dielectric strength - Wikipedia, the free encyclopedia

It's actually a pretty good article. Note that vacuum has a dielectric breakdown voltage, and one that is rather intermediate in their list of materials.

 

[M Gregg]

If you're reading Wikipedia, look at this:

Dielectric strength - Wikipedia, the free encyclopedia

It's actually a pretty good article. Note that vacuum has a dielectric breakdown voltage, and one that is rather intermediate in their list of materials.

Yes the vacuum is interesting also the difference with extruded teflon Vs Film.

Looking at:

Avalanche breakdown - Wikipedia, the free encyclopedia

http://en.wikipedia.org/wiki/Disruptive_discharge

http://en.wikipedia.org/wiki/Breakdown_voltage <<<<vacuum

I still wonder about the reduction of insulation resistance over time. Apart from contamination and absorption which would make sense. The ambient temperature effects the insulation properties. However it does not say if this returns as ambient drops to normal. Or if the damage is done!

Regards
M. Gregg

 

[SY]

Electron avalanche - Wikipedia, the free encyclopedia

More applicable to materials like plastic or gases.

 

[BudP]

Two issues with dielectric materials in use. Temperature is an aging multiplier and corona is also. In transformers we exclude oxygen molecules, to the best of our ability, to allow maximum mtbf from the dielectric barriers that keep electrical gear from becoming Darwinian selection devices.

Different materials require different storage mechanisms to keep them from aging due to other environmental threats. An example is Kapton film, which must be kept from moisture and cold temperatures, which will accelerate that materials aging.

Bud

 

[M Gregg]

Thank's Bud,

Thats realy interesting.

Open question.
So what is happening to the materials to enable reduced resistance or increased conduction to take place? (aging)

Regards
M. Gregg

 

[M Gregg]

Thought I would post this because I found it interesting.

http://www.ipme.ru/e-journals/RAMS/no_21306/amin.pdf

Not quite what we are covering but still interesting!

Then this:

http://www2.le.ac.uk/departments/en...lectrical-insulation-and-dielectric-phenomena

Seems to be much closer.

Regards
M. gregg

 

[M Gregg]

This again may be interesting to some,

http://eprints.ecs.soton.ac.uk/16113/1/04543118.pdf

Just for interest.

http://www.allaboutcircuits.com/vol_1/chpt_12/8.html <<<easier

Over to SY's book I think.... Shive and Weber, "Similarities in Physics."

Regards
M. Gregg

 

[M Gregg]

I will have to look up the Electronics .com info above

I find the flash over of paper compared to a vacuum incredible.


Explains a few cathode resistor failures.

Now compare Air and a Vacuum....


Regards
M. Gregg