600 volt, 3 phase surge protection

[mivey]

I've never seen a solid state device fail owing to mechanical force. So, the probability of such an event is vanishingly small in my experience.

It is obvious in your picture in #66 that the mechanical stresses caused the catastrophic failure. The melting was a secondary event caused by the shrapnel.








Not!

 

[Besoeker]

It is obvious in your picture in #66 that the mechanical stresses caused the catastrophic failure. The melting was a secondary event caused by the shrapnel.

After it had taken down a bunch of innocent bystanders, a stray dog, and a red light.....

Slightly more seriously, I have observed mechanical movement from resulting from high currents though not anything remotely close to being a catastrophic failure.
I'm sure such failures can and have happened with some systems.

But, my simple point to the Maharajah is that I have never seen such a failure on a solid state device. It would seem that he hasn't either.
Hence my comment about improbability rather than impossibility.

 

[T.M.Haja Sahib]

Bes the general secretary,
But improbable is no fact. So destruction of SPD by mechanical force of current is a possible event, irrespective of you agree or not.

 

[Besoeker]

Bes the general secretary,
But improbable is no fact. So destruction of SPD by mechanical force of current is a possible event, irrespective of you agree or not.

Hence my comments about improbability rather than impossibility.
See post #82.

 

[T.M.Haja Sahib]

Hence my comments about improbability rather than impossibility.

You admitted the possibility. :thumbsup:
See

Bes, why fixated on the idea of SPD destruction by thermal energy of current only? Consider the possibility of its destruction by mechanical force of the current and either can occur independently.

 

[Besoeker]

You admitted the possibility.

But not the extreme improbability
.

 

[T.M.Haja Sahib]

I was thinking you got rid of at least one of your fixations. :slaphead:

 

[Besoeker]

I was thinking you got rid of at least one of your fixations. :slaphead:

Which part of this don't you understand?

I've never seen a solid state device fail owing to mechanical force. So, the probability of such an event is vanishingly small in my experience.

Where is the possibility of mechanical failure, however remote, excluded?
It isn't.

I thus conclude that you're arguing for the sake of arguing on a topic of which, by your own admission, you have zero experience.
Unless you have something of substance to add, I suggest you add nothing.

 

[T.M.Haja Sahib]

Where is the possibility of mechanical failure, however remote, excluded?

Here

But not the extreme improbability
.

Thus
Bes, you contradict yourself.

 

[mivey]

I suggest you add nothing.

Status quo?

 

[Besoeker]

Bes, you contradict yourself.

There is no contradiction between the meaning of a remote possibility and an extreme improbability.

Now, do as I suggested and toddle off unless and until you have something useful to contribute.

 

[T.M.Haja Sahib]

There is no contradiction between the meaning of a remote possibility and an extreme improbability.

The problem is you admit neither the remote possibility nor the extreme improbability.

 

[T.M.Haja Sahib]

Now, do as I suggested and toddle off unless and until you have something useful to contribute.

At least you should be kind enough to admit me in the role of a reporter interviewing you, a mega expert on solid state devices. Will you, Bes?

 

[Besoeker]

The problem is you admit neither the remote possibility nor the extreme improbability.

My post #74 "So, the probability of such an event is vanishingly small in my experience."
A vanishingly small probability is an extreme improbability.

I have given my opinion on failure mode with my justification for it based on physics and on experience. I included a picture in support of that opinion.

Here are a couple more pictures* of a fairly big device - I put a ruler next to it for scale.
The interdigitated structure might or might not give you a clue about what this particular device is.

The second picture is a close up of the damage. Once again it clearly shows melting, this time in several places.
Things generally

Now, unless you are going to add something constructive or informative to the thread, I suggest you scuttle off.

*The quality of the pictures. They were taken with a pretty inexpensive digital camera.

 

[T.M.Haja Sahib]

My post #74 "So, the probability of such an event is vanishingly small in my experience."
A vanishingly small probability is an extreme improbability.

My only point which you never seem to grasp is

But improbable is no fact. So destruction of SPD by mechanical force of current is a possible event, irrespective of you agree or not.

 

[kwired]

He said the possibility is very small, not that it was impossible. He then mentions that in his years of experience he has never seen it happen, even more confirmation that it is not likely, yet he never used the word impossible just in case there is ever that rare occasion. Why can't you leave it for what it says, or show us some evidence on the contrary?

 

[Besoeker]

He said the possibility is very small, not that it was impossible. He then mentions that in his years of experience he has never seen it happen, even more confirmation that it is not likely, yet he never used the word impossible just in case there is ever that rare occasion. Why can't you leave it for what it says, or show us some evidence on the contrary?

Thanks kwired.

 

[Besoeker]

My only point which you never seem to grasp is

But improbable is no fact. So destruction of SPD by mechanical force of current is a possible event, irrespective of you agree or not

Improbable doesn't mean impossible hence my comments about improbability rather than impossibility.

So let's get back to the topic.
I've provided information, experience and pictures of my basis for catastrophic failures of solid state devices being a result of excessive energy.
Yet you call my experience questionable (whilst you have none) and suggest mechanical failure could be a possibility.
No one has denied that such a possibility exists. However remote that possibility might be.
And no one, yourself included, has actually cited a single example of such a failure. Not a single one.

So, I think the topic has been done to death.
If you have something constructive to add, put up. Otherwise shut up.

 

[wirenut1980]

mike_kilroy,

It is about the heating effect in each case.
With the high amplitude currents for short durations you get the intense localized heating damage because the power is so intense it does not have time to spread out via thermal conduction.

Often times manufactures play games with joule ratings. From the data sheet note that the 360 joule rating is at 2 milliseconds.

Regarding your above example:
The 8/20 figure is not a division. It is stating an 8 usec rise time and 20 usec decay to 50% level waveform. To be totally accurate you need a complex equation but you might approx. it by using 20 usec. Then the numbers come a lot closer. Next consider that the clamping voltage will be much greater at the higher current (Perhaps as much as a factor of 3x).

I think this post should have pretty much ended the discussion, but it remains. Well said ELA.

I always took the max current rating from the manufacturer to mean that for surge currents above that rating, the SPD is not guaranteed to protect the load. (Due to thermal heating, :lol.

 

[T.M.Haja Sahib]

If you have something constructive to add, put up. Otherwise shut up.

Listen, Bes. You never said any thing about the possibility of the SPD destruction by mechanical force of current until I brought it up. Don't you think it is something constructive?

Moreover I brought up this possibility to stress the fact that a SPD can be destroyed by the action of current alone without its surge energy any thing to do with it.

I think now things are clear to you. Are not they?