Identity of this component that caught fire so I may curse at it properly - Page 1
Forum section: electronics / beginners

author: Purduephotog
author_rank: Regular Contributor
timestamp: October 17, 2017, 01:58:22 am
content: Just had an event. Swore I heard chirping... Figured out eventually it was the UPS. Many words used.What is this component that appears to have melted and vented? The relays are shot too... Figure that was the plastic smell.Fuse intact, the GFCI outlet that fed it tripped. Smoke alarm didn't trigger.

author: ataradov
author_rank: Super Contributor
timestamp: October 17, 2017, 02:18:09 am
content: Looks like a capacitor. See what the remaining labels say.

author: Purduephotog
author_rank: Regular Contributor
timestamp: October 17, 2017, 02:33:07 am
content: Yeah... Soon as I can stand the smell. Breathing is still tough.Looks like it was a cardboard tube with actual leads and one of which went thru what looked like a current sense.I'll try for a better photo later. Just pissed off.

author: David Hess
author_rank: Super Contributor
timestamp: October 17, 2017, 03:58:05 am
content: It is a plastic film capacitor but I do not think it is part of differential (X class capacitor) or common mode (Y class capacitor) interference suppression because of that AC current transformer. Instead, I suspect it is the series capacitor in a resonate switching converter.

author: fonograph
author_rank: Frequent Contributor
timestamp: October 17, 2017, 05:00:55 am
content: What is that device? What year was it manufactured?

author: David Hess
author_rank: Super Contributor
timestamp: October 17, 2017, 05:06:53 am
content: Quote from: fonograph on October 17, 2017, 05:00:55 amBased on the visible date codes, it was manufactured in the second half of 1995.

author: onesixright
author_rank: Frequent Contributor
timestamp: October 17, 2017, 07:08:59 am
content: , looking at the components around the cap (?), guessing, it got freaking hot!

author: Gyro
author_rank: Super Contributor
timestamp: October 17, 2017, 08:42:58 am
content: Quote from: David Hess on October 17, 2017, 03:58:05 amYes, definitely a plastic film capacitor, too big to be an X cap. Possibly to try to clean up the output waveform of the UPS. It's not a moisture sensitive Rifa metalized paper so those comments don't apply. It has maybe suffered an overstress (instant or over time) which has caused it to self-heal itself to death.If you're lucky, you may be able to read the value but given that you will need to replace the melted relays etc. and de-carbonize the PCB, it is probably beyond reasonable resurection.Edit: Looking at the amount of metal, it may even be a film and foil type (non-self healing) rather than metalized film.

author: stj
author_rank: Super Contributor
timestamp: October 17, 2017, 09:44:41 am
content: if you fix it, make sure you use a very high current replacement.i know they make them for solar devices.

author: NivagSwerdna
author_rank: Super Contributor
timestamp: October 17, 2017, 12:25:15 pm
content: C6 looks a bit absent. Crack in relay and is that other relay really as melted as it looks?

author: Purduephotog
author_rank: Regular Contributor
timestamp: October 17, 2017, 04:54:18 pm
content: Quote from: NivagSwerdna on October 17, 2017, 12:25:15 pmIf by melted you mean slumped over and oozing like a classic surrealistic painting, yes.The second ups plugged into the outlet was dead battery. The big one (pictured) was flashing. It may have still been supplying power... I don't know.No I probably won't try to fix it. Burned all the way on the backside too. Fr4 is shot in that area.I'll salvage the big transformer and the mosfets... Or at least the sinks... But I think it's headed to the recycler.Batteries read 13.6v when I ripped them out.

author: Karlo_Moharic
author_rank: Regular Contributor
timestamp: October 17, 2017, 06:51:04 pm
content: Axial electrolytical capacitor

author: bjcuizon
author_rank: Frequent Contributor
timestamp: October 18, 2017, 08:08:01 am
content: Quote from: Karlo_Moharic on October 17, 2017, 06:51:04 pmYeah, its a cap..it has foil all over the place.This should be featured on EEVSmokeBy the way, @Karlo_Moharic I thought you were Simon for a while. Hehe

author: Gyro
author_rank: Super Contributor
timestamp: October 18, 2017, 08:33:38 am
content: Quote from: Karlo_Moharic on October 17, 2017, 06:51:04 pmNope, sorry. An electrolytic would vent through the end with the seal. That one is plastic encapsulated, no Aluminium can.

author: Purduephotog
author_rank: Regular Contributor
timestamp: October 21, 2017, 01:42:25 am
content: Quote from: bjcuizon on October 18, 2017, 08:08:01 amIt certainly smoked- the whole house reeked for a day until I got the fumes dissipated. Has convinced me to install one of the big 8" turbo fans I have out a window, such that I can vent the house. Oh well, another project.In all honesty, thanks everyone for the help. I've mailed APC; they requested photos, I've sent them, no followups since then. Really just wanted to know what happened, if it was a known issue, and whether or not to junk any/all other units I've got or do PM/replacement on them. It's hard to find good UPSs at decent prices (for a reason, I know).The main unit was going to be rewired to work off a flooded marine battery with 200AH capacity. Power the VOIP, phone, modem, and router. I'm going to be rethinking that for a bit and include some sort of firesupression or chemical fire retardant in an easily disintegrate bag (if fire, dump fire suppressant).

author: Gregg
author_rank: Super Contributor
timestamp: October 21, 2017, 02:27:35 am
content: Fire suppressant can get awfully messy, especially the white powdered stuff that becomes conductive as soon as some moisture gets to it. A CO2 fire extinguisher would be a better bet. Halon used to be an option, but is frowned upon by environmentalists.What you need is an emergency power off switch (EPO) that will disconnect both the battery and line in. Without power to sustain the fire, circuit board fires usually don't burn too long; the smell is another issue.