Overvolting/reversing a polymer cap

[Rodalco]

Re: Overvolting/reversing a polymer cap

I am in for blowing stuff up. Have 240-270 Volts with 32 Amps with 35 Amp variac to test with. Cap bank with 5 x 20 UF 6.6 kV Caps, but 14 Caps in total. Then 630 Volts at around 10 Amp to experiment with. Did a TV test with an old CRT TV which worked up to nearly 500 Volts AC.
First smoke the TV out with some smoke tablets, then ramp up the voltage to 320 and 420 and 490 Volts till the TV popped. great fun.

https://www.youtube.com/watch?v=mnMnOn_uU8U

[eccerr0r]

Re: Overvolting/reversing a polymer cap

To be honest, blowing up capacitors is not fun to me. The sole reason for blowing up the caps is to match behavior, assuming similar behavior means similar design. Yeah it's a bit of correlation is not causation but all these capacitors look so much alike, they all behave like capacitors, etc.

So, how to tell them apart? Destructive testing. Yes, opening them is destructive as well, but capacitors are all still spiral wound foil. So how else to tell them apart? Testing (inspecting) for dryness is kind of "soggy" (how do you tell? touch it? need it to evaporate?)

[Uranium-235]

Re: Overvolting/reversing a polymer cap

I put a 16v poly in a monitors 25v line. It worked fine all night, next day, sounded like a firecracker went off. Can was popped off

[eccerr0r]

Re: Overvolting/reversing a polymer cap

Interesting... so the videos aren't correct or not always typical?
Did the lead fuse or did it actually out gas?
Are you sure you have a real poly?

... do we need to open them, sniff them, and see if we get high on the https://www.badcaps.net/forum/showthread.php?t=74467 vapors to tell what it is?

[stj]

Re: Overvolting/reversing a polymer cap

solids can change, gas or heat-up(and potentially burn or explode)

[eccerr0r]

Re: Overvolting/reversing a polymer cap

Well, I never expected melt, but heat expansion is possible as well as electrochemical activity. Just wondering if the movie presented is typical behavior if subject to improper conditions.

The movie still didn't demonstrate reverse polarity, so that's still a mystery