Things that go pooof/pop

[crust]

Along the lines of popping electrolytics. When I was a graduate student, I took a power electronics class which had a lab component. In the lab part one of the early projects was to build a buck converter. Rather than write your name on it though, you were to put an assigned number. Then the professor would randomly reassign projects. So now you had somebody elses (and you didn't know who) and some third person had yours. Then you had to debug their circuit and modify it (first to a boost, then you exchanged again and modified it to a buck-boost). In any case, one person mounted the cap backwards, but it managed to work (at least to some extent) for the few days they modified the project. But when the next person got the project, as they were working on it, the cap went off like a shotgun. It was *loud*, though the ensuing laughter was even louder.

 

[zachtheterrible]

It is, a high voltage current limited source (like the 25-30KV in a TV), doesn't have enough current to harm you, and it's why earth leakage trips (GFI's) trip out when a specific current leaking to ground occurs.

thats wut i thought!! (am i igniting a theory discussion here?)

 

[mstechca]

wanna pop a capacitor the most idiotic way?

do this:

step 1: take a refrigerator and snip the plug wire.
step 2: remove about 1/2 inch insulation at the end you cut. this end must be able to plug into the wall.
step 3: separate the ends so that the wire forms a Y shape.
step 4: connect an electrolytic capacitor with a low voltage rating (say 10V) to the wires. Now you will have a complete circuit.

and the fun step, step 5: PLUG IT IN!

and if you want to get more crazy, smash your monitor and take a capacitor from it.

Ok, I'm just being silly now, but hey, I'm following the subject

 

[jrz126]

I can make that much simpler, Just use a capacitor with long leads and cram it in a wall outlet. no refrigerator cord cutting needed

 

[zachtheterrible]

cheap extension cord if u dnt want a big brown burn spot on ur outlet :lol:
i REALLY gotta try this. i got a couple boards full of 100, 220, 100 uf 10v caps :twisted:

 

[zachtheterrible]

:twisted: hee heeeeeeeeee :twisted: i tried the cap popping w/ wonderful results. this is my tutorial for newbie cap poppers:

find an old piece o junk extension cord. i have a couple that are used for attaching things like christmas lights. now cut off about 6 inches so u have a piece of cord w/o the plugs. strip both ends of the cords. now put alligator clips on two of the ends. now attach the your capacitor to the alligator clips. make sure that you attach the clips as close as u can to the capacitor otherwise u might fry the capacitor's leads because they aren't meant for 120v :twisted: (thats where i went wrong). plug the other two ends of the cords into your extension cord OBVIOUSLY WHEN THE EXTENSION CORD IS NOT PLUGGED IN, DUH!!!!

now wut i like to do is plug the extension cord into my powerbar when the powerbar is not turned on. that way i have a switch that i can flick. also, the powerbar will automatically shut off if your two clips accidently touch each other, then u dont have 2 go out to the breaker box

dont use capacitors w/ vents on the top. if it has lines on the top of it, that means it has a vent. only use capacitors that are solid on top. the vents are there so that when the cap gets connected to too high of voltage, it doesnt blow up, it just goes ssssssssssssss. BORING :roll: !!


now, questions:
wut makes the biggest boom? i was using 47 uf caps rated @ 50v. i thought i had a bunch of 100 uf caps n stuff but i didnt.

i take it the voltage rating should be low and the uf high as u can get it.

where might i find some big caps w/o the bloody vents? i was thinkin of going to a thrift shop and picking up some really old piece of electronic equipment.

 

[jrz126]

The bigger cap value the better, also as long as the voltage rating is below 120Vrms, or maybe it could be above 120V because it's actually 169.7Vpeak. If it wasnt starting to snow here, I'd play with some LARGE caps that I have sitting around :twisted:

Maybe you can put some epoxy over the ones with the vents to seal them up for a bigger boom. :twisted:

Old electronics is great to salvage from. make sure it's the older stuff though, the newer stuff uses that surface mount stuff which cant be salvaged.

 

[ante]

Hi Jeff,

I like to see the chainsaw where the piston fits!

 

[jrz126]

It's not from a chainsaw, its from my lawn mower. :lol:
**broken link removed**
**broken link removed**
https://www.cardomain.com/member_pa...mages/3/web/435000-435999/435572_131_full.jpg

But seriously, if you're wondering, I got it from salvage at work, it's for a 4400 HP desiel locomotive engine. Paid 10 cents a pound so it cost me $13.70 (137 lbs :wink: )

It's amazing to think about 16 of these 137 lb pistons moving up and down 1170 times a minute.

I'm looking into possibly selling it if anyone is interested

 

[Nigel Goodwin]

That's only a baby piston!.

I watched a program a while back on a Korean ship builder, they make the biggest ships and biggest engines in the world. I can't remember the exact size of the pistons, but there was an access DOOR to the big ends, where you could walk in and examine them!. Certainly the pistons were measured in feet, not inches :lol:

 

[jrz126]

Yeah, yeah yeah...my friend was showing them to me online. but I'd like to see you fit one in your garage.
Seems like everyone I talk to about my piston always brings up the pistons in ships.

what exactly do you mean by the big ends? the upper half where the comression actually takes place?

 

[Nigel Goodwin]

Yeah, yeah yeah...my friend was showing them to me online. but I'd like to see you fit one in your garage.
Seems like everyone I talk to about my piston always brings up the pistons in ships.

That's because that's where BIG pistons are found :lol:

what exactly do you mean by the big ends? the upper half where the comression actually takes place?

No, the 'big end' is the bearing at the lower end of the connecting rod, the 'little end' is the bearing at the top of the connecting rod (inside the piston).

 

[Evil_Genius]

Big Ship Engines

**broken link removed**

Big End vs Little End. Pic = 100 words.

Everything is relative. Note the railing and the ladders. And only 6 cylinders. The term "to throw a wrench into the works" refers to just how easy it was to destroy such engines. They have such a slow cycle that you could easily toss a large tool into the cylinder via an open valve, and destroy the entire cylinder.

 

[jrz126]

At my place of buisness, they had some problems with some of the engines, and it turns out that some mechanic did in fact leave a wrench in there.