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0toShifty posted:And the tire BECAME the Michelin Man. Wow that tire is hosed. Edit quote for new page
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Aug 17, 2016 02:02
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I wonder if there was any visible damage on the outside.
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Aug 17, 2016 03:09
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Edit for clarity We found the cause of this  it was 0toShifty posted:And the tire BECAME the Michelin Man. tater_salad fucked around with this message at 20:26 on Aug 17, 2016 |
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Aug 17, 2016 03:51
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tater_salad posted:We found the cause of this Well, yeah, but don't post it here. Wouldn't want to know why.
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Aug 17, 2016 04:00
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charliemonster42 posted:Well, yeah, but don't post it here. Wouldn't want to know why. 0toShifty posted:And the tire BECAME the Michelin Man.
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Aug 17, 2016 04:34
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Tire exploded from dragging/stuck caliper causing heat, right?
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Aug 17, 2016 04:52
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Look straight up, that speck you can barely see in the sky is the joke.
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Aug 17, 2016 04:53
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Somehow, two bolts have failed.   600V 1200A bus running at 350-400A if anyone cares.
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Aug 18, 2016 01:55
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Holy poo poo, 280c?
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Aug 18, 2016 02:10
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If it’s only 280°C, it’s not glowing in the visible range, but it sure makes a nice photo.
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Aug 18, 2016 02:14
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Cojawfee posted:Holy poo poo, 280c?
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Aug 18, 2016 02:16
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nmfree posted:>280°C (that's the upper limit of the FLIR?), and I'd guess well past that, since the nuts are glowing in the first pic. Yeah, my camera has a max of 280˚C. Anything over it just says >280˚C. The actual wire got to 160˚C, which is super bad for something rated at 90˚C. Only replaced the lug and bolts though.
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Aug 18, 2016 02:21
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DocCynical posted:Somehow, two bolts have failed. What is that 720kW bus feeding? The glowing nuts are... ffffuuuuuccccckkkkk 
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Aug 18, 2016 02:22
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Platystemon posted:If it’s only 280°C, it’s not glowing in the visible range, but it sure makes a nice photo. That bottom bolt is most certainly glowing.
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Aug 18, 2016 02:36
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HandlingByJebus posted:What is that 720kW bus feeding? 1200A at 600V 3ø is 1.2MW. Forgot a √3 in your calculation. Unless you are just talking about the single bus bar... It feeds a 350 person camp with the kitchen and amenities in the middle of nowhere. Had to get the power linemen to disconnect the transformer fuses at the pole. Just switched to generator while we fixed it up at 9 or so at night, the power linemen didn't know which fuses did the transformer that fed this.
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Aug 18, 2016 02:37
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Items glow in infrared, invisible to the human eye but very visible to a digital camera, before they glow visually.CommieGIR posted:That bottom bolt is most certainly glowing.
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Aug 18, 2016 02:40
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DocCynical posted:1200A at 600V 3ø is 1.2MW. Forgot a √3 in your calculation. Unless you are just talking about the single bus bar... P = VA Which gives you 720kW.
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Aug 18, 2016 02:40
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Geirskogul posted:Items glow in infrared, invisible to the human eye but very visible to a digital camera, before they glow visually. It wasn't glowing as brightly as the camera shows, but it was definitely glowing red. Judging by a steel colour chart, the temp is ~580˚C on the nut itself, from what I remember. EightBit posted:P = VA
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Aug 18, 2016 02:46
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Honestly just dismissed it as some kind of anodized bolt for some reason.
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Aug 18, 2016 02:51
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DocCynical posted:Only on the one phase, the total system power is 1.2MW. 720*(√3), right? I have the vaguest recollection of first year physics telling me that.
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Aug 18, 2016 02:53
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Memento posted:720*(√3), right? I have the vaguest recollection of first year physics telling me that. This. I forgot the other phases. Schooled! 
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Aug 18, 2016 03:01
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Memento posted:720*(√3), right? I have the vaguest recollection of first year physics telling me that. P=ELine to Line*ILine*√3. So, 600V*1200A*1.723(ish) is 1.2MW. If we are getting mathy in the mechanical failures thread for some reason, then you could also go P=ELine to Neutral*ILine*3, which would be 347V*1200A*3=1.2MW. A single bus would be just 347V*1200A = 416kW. This is all assuming unity power factor of course. [/maths derail]
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Aug 18, 2016 03:02
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Paging Three Phase to the thread, this is extremely your poo poo.
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Aug 18, 2016 03:27
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DocCynical posted:It wasn't glowing as brightly as the camera shows, but it was definitely glowing red. Judging by a steel colour chart, the temp is ~580˚C on the nut itself, from what I remember. Interesting. I was going by the second image where the scale tops out at 260.4, but I guess overexposure was allowed there
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Aug 18, 2016 03:33
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Platystemon posted:Interesting. I was going by the second image where the scale tops out at 260.4, but I guess overexposure was allowed there I may have snapped that one after the power had been cut and after a while. I don't recall, this happened last year sometime I think. The big picture was shot with my cellphone and then the two thermal ones with the Flir, which does have a digital camera, but at 640x480 or something lame. I may have used the software to futz with the scale as well to try and enhance the temperature differences.
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Aug 18, 2016 03:53
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DocCynical posted:Somehow, two bolts have failed. Who made those bolts, because I want to buy stock in that company.
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Aug 18, 2016 04:57
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DocCynical posted:Somehow, two bolts have failed. what was the reason for this failure? Was this so hot because those 2 bolts were loose so got all the current rather than the whole of the metal mating surfaces? or was everything just overloaded and overfused?
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Aug 18, 2016 14:16
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Tomarse posted:what was the reason for this failure? I assumed it was because the bolts weren't tight enough... am I close?
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Aug 18, 2016 14:27
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EVERYWHERE 
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So close that you're arcing.
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Aug 18, 2016 14:57
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Tomarse posted:what was the reason for this failure? Poor load balancing, too much of the load is on that phase. Otherwise the wires wouldn't be running at 160C as well. Someone who knows what they are doing needs to take a look at it and figure out how to split things up better.
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Aug 18, 2016 15:27
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rdb posted:Poor load balancing, too much of the load is on that phase. Otherwise the wires wouldn't be running at 160C as well. Someone who knows what they are doing needs to take a look at it and figure out how to split things up better. Nope, everything was still balanced. The bolts came loose and instead of 350A going through the lug and bus bar surface area, it was close to all of it going through the two bolts. Much less surface area and cross sectional area as well as steel not being as good a conductor. It is slightly hard to see in the photo, but that lug is really only contacting at the top. The wire heating is from the bolts, copper conducts heat well. As to why the bolts failed in that manner, I have no clue. Maybe they worked loose via vibration from the 1.2MW backup generator being tested. Maybe they weren't torqued right and just worked loose over time. It happened quick though. Day before everything was fine.
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Aug 18, 2016 16:22
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I wonder how fast loctite would burn off on something like that.
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Aug 18, 2016 16:40
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Seat Safety Switch posted:I wonder how fast loctite would burn off on something like that. How much current are cotter pins rated to?
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Aug 18, 2016 17:08
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I know the food industry uses stainless steel lock nuts, they're my preferred nut for trailer hitches/towbars.
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Aug 18, 2016 17:14
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Isn't stainless a fairly weak metal, though? Like "grade 2"?
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Aug 18, 2016 17:52
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QuarkMartial posted:Forgot about a bic lighter on my dash for a while and it burst earlier in the summer. Wasn't driving or even in the car, or it could have ended badly. Really surprised to hear that, I always assumed the cheap-o's overheat and explode because they are translucent.
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Aug 18, 2016 17:54
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Maybe in general don't leave sealed containers of volatile, flammable substances in direct sunlight/hot cabins.
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Aug 18, 2016 18:00
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You can't tell me what to do.
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Aug 18, 2016 18:01
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Safety Dance posted:You can't tell me what to do. Continue to take up space.
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Aug 18, 2016 18:02
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Whatever, dad.
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Aug 18, 2016 18:03
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