Vanished pbc tracks (just want to share failure pictures)

[Miyuki]

Hi
I'm experimenting with design of welding inverter, full bridge topology
Yesterday I have spectacular failure, it was really BIG BANG
It use huge capacitor 4700uF at ~400V with datasheet ESR just 40mOhm so it have lot of pretty fast energy (I buy them cheap as old stock)

It was huge bright flash and stunning bang. When I turn everything off there was no visible damage at first but at second look, just see on your own eyes:

[alm]

Is this a case where you should cover tracks in solder for increased current handling capacity?

It was huge bright flash and stunning bang. When I turn everything off there was no visible damage at first but at second look, just see on your eyes:

Eye protection indeed sounds like a good idea.

[capt bullshot]

Been there, done that long time ago ...

But your results looks really clean and surgical, congratulations!

[Miyuki]

Is this a case where you should cover tracks in solder for increased current handling capacity?

In this case tracks worked as a good fuse, must measure transistors, they are not shorted (maybe opened will see), rectifier with PFC boost is intact and continue to work fine

[alm]

If the transistors survived, then you are lucky. Failures in these kind of circuits tend to take a whole bunch of expensive power semiconductors with them.

[MK]

usually expensive power transistors lay down their life protecting the fuse...

[hermit]

Not bullet proof, but a good place to start:

http://www.circuitcalculator.com/wordpress/2006/01/31/pcb-trace-width-calculator/

[DBecker]

Not bullet proof, but a good place to start:

http://www.circuitcalculator.com/wordpress/2006/01/31/pcb-trace-width-calculator/

That's probably not useful here.  These traces didn't overheat from a minor error in design calculations.  They delaminated so quickly that not even a scorch mark was left.

[ConKbot]

Impressive that there isn't any vapor deposited copper/copper oxide left either. I've put 30awg wire across a photoflash cap bank switched by a chunky SCR (intended for powering a disk launcher) and it left a nice copper colored coating on the binding posts. Perhaps the pcb glue (holding down the copper) vapor cloud pushed the copper vapor cloud away.

[marshallh]

Very impressive, top marks not even a single burn mark!

[alm]

Just nature's suggestion for a change in PCB layout I guess .