Vaporized fuses? - Page 1
Forum section: electronics / general

author: ftransform
author_rank: Frequent Contributor
timestamp: March 31, 2013, 03:24:55 am
content: So, I had an appliance crap out on me with a fuse. The fuse is in the type of holder that prevents it from sliding out, it has little tabs that prevents it from doing so.This fuse popped while the appliance was working (with a loud bang no less). Had it not been for the copper vapor that condensed on the PCB and the housing above it I would have thought that someone forgot to put a fuse in.I would have thought that the endcaps for the fuse would have remained inside of the holders, but there is literarly no trace of it, unless it shot out and fell somewhere deep into the appliance, but that compartment is pretty well sealed, and there is of course no trace of glass.Did the whole fuse literally vaporize? Or do I need to look further?I have no idea what kind of fuse it was, ceramic or glass or what.The fuse holder is of this type:http://ram-e-shop.com/oscmax/catalog/images/thumbs/Fuse_holderS.JPG

author: NiHaoMike
author_rank: Super Contributor
timestamp: March 31, 2013, 04:32:10 am
content: Maybe they cheaped out and just used a strand of wire?

author: SeanB
author_rank: Super Contributor
timestamp: March 31, 2013, 06:35:51 am
content: They are in there somewhere, you probably should find then as they may fall on something else and blow it as well. Replace with a ceramic version of the fuse, using the right rating. That is why you do not use glass fuses on mains, if there is enough energy in the circuit then the fuse explodes. The ceramic at worst will crack, it is much more able to withstand the energy of blowing.

author: Rerouter
author_rank: Super Contributor
timestamp: March 31, 2013, 06:42:50 am
content: its not really the energy of blowing, rather the very rapid increase in temperature and pressure of the air captured inside the thing which sometimes shatters the glass,

author: ftransform
author_rank: Frequent Contributor
timestamp: March 31, 2013, 07:19:36 am
content: Quote from: SeanB on March 31, 2013, 06:35:51 amSamsung fails.

author: Psi
author_rank: Super Contributor
timestamp: March 31, 2013, 08:34:11 am
content: They might be doing the same thing i doI put a fuseholder on the PCB but ship the product with no fuse installed, Instead i have a secondary SMT fuse in parallel with the holder.That way i save money (SMT fuses are cheaper) and the consumer can always put a glass fuse in if it blows.

author: NiHaoMike
author_rank: Super Contributor
timestamp: March 31, 2013, 05:23:13 pm
content: That doesn't make much sense since it's usually a shorted primary side semiconductor that blows the fuse.

author: ftransform
author_rank: Frequent Contributor
timestamp: March 31, 2013, 06:02:15 pm
content: That's what I thought at first (aftermarket fuses). See the first half of the appliance blew a long time ago, and I did not know why (I thought a mosfet failed, its a induction stove).So two burners worked.Now the same failure happened (by putting a pot which is not ferrous enough, causing it to overload). I remember one fuse being missing with a tiny scorch mark, but this was several years ago, I don't remember if the other fuse was present. This was before I really got into electronics, so I figured no burnt out fuse = no fuse installed at factory, and it was some kind of manufacturing defect.I have been thinking back for a while now, and I think that there was in fact 1 glass fuse (which has now went kaboom), but I might be making this memory up.I don't understand why samsung would skimp out on fuses in a expensive stove...But the two condensed copper spots/burn marks on the metal casing above the fuse holders clearly show there were two explosions.I feel like a fail because I used this stove with two burners for the last 3 years, when all I had to do is replace a fuse (I hope).What I think happened is the litz coil discharged into ground and blew the fuse up. The first time this explosion happened I was standing right near the stove and I heard a loud explosion and saw a very bright spark (through the heavily tinted glass). I was trying to make pastrami by pressure cooking roast beef with spices, but I did not realize the pot I was using was made of aluminum. Normally the stove has a sensor which needs to detect a ferrous metal but it turned out that the little tray inside the aluminum pressure cooker (so the food being cooked is outside of the steam water) was made of steel, which triggered the sensor, and allowed current into the coil, somehow causing an overload and a spark to jump.I never looked on the bottom of the covering for litz coil electronics because it is a heavy lid, so I just set it aside and looked at this PCB.Let this be a lesson, look beyond the PCB for clues into device failure.I felt like it was the horror movie where everything looks alright, then the guy looks up and he sees the monster/body hanging from the ceiling.

author: M. András
author_rank: Super Contributor
timestamp: March 31, 2013, 06:25:04 pm
content: wait isnt induction heating supposed to work on every metal?

author: NiHaoMike
author_rank: Super Contributor
timestamp: March 31, 2013, 06:32:23 pm
content: Aluminum and copper are more conductive than iron, so they could possibly overload an induction heater designed to only work with iron.

author: SeanB
author_rank: Super Contributor
timestamp: March 31, 2013, 06:55:45 pm
content: You need a ferrous material to get the inductance high enough in the coil. You do get pots and pans with a copper bottom and a steel insert specifically for induction cooker use. I just use cast iron cookware.

author: ftransform
author_rank: Frequent Contributor
timestamp: March 31, 2013, 06:59:28 pm
content: I am so fucking annoyed by these fuses, I have no idea what type I need because they disappeared and its not written on the board.These fucking dickheads want me to buy a god damn manual so they can tell me what value of a fuse I need? Jesus H chirst I wanna go vandalize Samsung corporate headquarters right now.Fuck their god damn mother fucking piece of shit sales model.Also fuck people who sell manuals. Just post the copies online and find some other way to make yourself useful to society and earn a wage. Fucking pieces of shit keeping information hidden for profit. It's like some form of extortion. Human beings make me sick. The thought of paying 25$ for a god damn amperage value makes me sick.

author: c4757p
author_rank: Super Contributor
timestamp: March 31, 2013, 07:08:20 pm
content: I think you missed a "fuck" right around the third sentence or so.

author: SeanB
author_rank: Super Contributor
timestamp: March 31, 2013, 07:11:49 pm
content: Model number?

author: ftransform
author_rank: Frequent Contributor
timestamp: April 01, 2013, 01:17:01 pm
content: I swear to god that god damn fuse vaporized there is no sign of it anywhere. I suppose it might have fell through the tiny hole on the side somewhere into the ovens insulated walls.....

author: SeanB
author_rank: Super Contributor
timestamp: April 01, 2013, 04:50:47 pm
content: Generally in an oven, stove or microwave the fuses are invariably in the region of 10A, though some are 15A. If it has the old ES screw in fuses they were normally 15 and 20A units.

author: M. András
author_rank: Super Contributor
timestamp: April 01, 2013, 07:52:50 pm
content: they could simply use din rail mounted circuit breakers would be better then a little glass or ceramic fuse