# Testing Vacuum Bottles



## Big John (May 23, 2010)

I don't know of any industry standard for failing a bad vacuum interrupter. The best I can say is that I've seen manufacturers specs that put acceptable leakage around 5uA, and in reality, I've tested bottles that were less than 1uA at 15kV. So it certainly gives an idea of what a good hipot would be.

I've never bothered with the dedicated bottle-testers because they often only give a pass fail reading, and that doesn't help with trending. A bottle may have jumped from 4uA to 40uA in a very short amount of time with few operations, but as far as a bottle-tester is concerned, it's still under the "trip threshold" so it's still good. Seems like those things could potentially allow you to overlook a serious problem. The only thing I can say to the advantage of dedicated testers is it avoids the risk that you can get with some DC hipots of accidentally exceeding the maximum test voltage on the bottle.

The best way I can suggest to the test in the absence of manufacturers data is to compare phases and compare vintages and look for severe deviations. 

Hopefully Zog pipes up because maybe he knows of a better standard. We actually just had a demo of a piece of equipment that he carries which can accurately trend vacuum integrity, and not just overall leakage like a hipot will. Looks pretty slick.


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## Zog (Apr 15, 2009)

We do that to all our bottles, it is how they do it at the factory when they build the bottles. Measure pressure, put it on a shelf for 6 months, measure pressure again, trend the data, and if it meets the 20-30 year design criteria it is shipped. We designed a way to conduct that test in the field, 15 years of R&D. 

Scary thing is VCB technology came out in the 80's, sold like crazy in the 80's and 90's, and now all those bottles are at that 20-30 design lifetime. The testing we do is based on the Penning discharge principle, which is interesting if you like molecular physics, but since not many do I will skip that, just goggle it if you care. 

Hipot test only tells you if it is good today, not if it will fail (And they fail dramtically) next week, or next year. We can actually say how much longer expected life is at the current leak rate. 2nd coolest thing we have invented.


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## GREGNC (Nov 13, 2007)

Our gear is 2300 volt we hipot the 
bottles every 6 months 5miliA or less
Is considered good.we also do
A micro ohm test with bottles closed
170 uohms or less is good. I have
Never done a hipot even close to
A fail.but we have changed out
Bottles due to micro ohm test.
Do any of you use micro ohm test?


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## Zog (Apr 15, 2009)

We see failed bottles every day. contact resistance does not tell you much for vacuum interrupters but it is a standard test. Contact erosion is a much better indicator of condition assessment.


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## GREGNC (Nov 13, 2007)

Do you feild test for other companies


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## Zog (Apr 15, 2009)

GREGNC said:


> Do you feild test for other companies


Yes, but more often it is part of a refirbishment in our shop.


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## Zog (Apr 15, 2009)

Here is what failures look like, usually there is damage to surrounding equipment, and sometimes people. 

http://vacuuminterrupterfailures.com/index.html


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## GREGNC (Nov 13, 2007)

We actually had one fail about 5 years ago
One bottle stuck when whem motor was cut off
Did quite a bit of damage at starter 
And lost a 1000 hp motor 
Fotunately no was hurt


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## GREGNC (Nov 13, 2007)

Zog said:


> We do that to all our bottles, it is how they do it at the factory when they build the bottles. Measure pressure, put it on a shelf for 6 months, measure pressure again, trend the data, and if it meets the 20-30 year design criteria it is shipped. We designed a way to conduct that test in the field, 15 years of R&D.
> 
> 
> are you talking about internal pressures of bottle or spring pressure to close contact


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## Zog (Apr 15, 2009)

GREGNC said:


> are you talking about internal pressures of bottle or spring pressure to close contact


Internal pressure of the bottle


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## Lone Crapshooter (Nov 8, 2008)

I want to thank everyone for their input.
LC


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