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-   -   anyother robots smoke up? (http://www.chiefdelphi.com/forums/showthread.php?t=45415)

65_Xero_Huskie 13-03-2006 21:51

Re: anyother robots smoke up?
 
Quote:

Originally Posted by Kevin Sevcik
I coached that match against them. Sadly, after they reset the field and removed 1189, Huskie forgot to completely reset their robot (thanks to the backup battery) and ended up going nowhere in autonomous instead of scoring all those balls. Not that we did much, as we were still dealing with a lot of other difficulties.

At any rate, I managed to talk with some guys from 1189 on saturday, and related our hard-luck story of losing a match cause an opposing robot went up in smoke. And then discovered that it was them. Apparently some battery leads got twisted up with some PWMs in their turret. Then they either got pinched or otherwise exposed and shorted. And thus full 12V to ground with no breaker. I was honestly wondering how you could possibly make that much smoke without tripping a breaker. I suppose it's good to know that you in fact can't.

lol, yea, we did forget to reset our bot...our faults...but we did learn that our aim on our camera was off from half field, so we adjusted that after that match :D

KenWittlief 13-03-2006 21:52

Re: anyother robots smoke up?
 
Quote:

Originally Posted by Dillon Compton
Thank god for the brave ref with good reflexes who grabbed the battery and, I kid you not, threw it a good twenty feet.

.

in who's direction?! where could you possibly throw a burning battery in the middle of a regional?

65_Xero_Huskie 13-03-2006 21:53

Re: anyother robots smoke up?
 
everyone around that robot started to move fast after that happened, anything coulda happened

GaryVoshol 13-03-2006 21:58

Re: anyother robots smoke up?
 
Quote:

Originally Posted by Kevin Sevcik
Apparently some battery leads got twisted up with some PWMs in their turret. Then they either got pinched or otherwise exposed and shorted. And thus full 12V to ground with no breaker. I was honestly wondering how you could possibly make that much smoke without tripping a breaker. I suppose it's good to know that you in fact can't.

Yep, 1189 showed us their video in Pit Admin - and then showed off the burned up length of PWM.

Idaman323 13-03-2006 21:59

Re: anyother robots smoke up?
 
Wow, last year at St. Louis regional.. there was a bot that had some pretty nice smoke coming out of it. Never knew what caused it though.

Dillon Compton 13-03-2006 23:09

Re: anyother robots smoke up?
 
Quote:

Originally Posted by KenWittlief
in who's direction?! where could you possibly throw a burning battery in the middle of a regional?

It was Nationals- they grabbed it, ran about ten feet, and pitched it into an unoccupied portion of the georgia dome floor. It promptly went out as the refs severly reprimanded us for having a faulty battery.

DjAlamose 14-03-2006 08:24

Re: anyother robots smoke up?
 
Quote:

Originally Posted by 65_Xero_Huskie
it was 1189, and i never found out, but i heard that it was a lose screw or something, ud have to ask them

This is what I have been told:
The camera wire somehow shorted out and caused an arc that caught their nylon fabric stuff on fire. The fire went out quickly but it still smoldered inside the electrical box. When they lifted up the cover they released the magic cloud. After they got back to their pits everything was fine and nothing (except the fabric) was damaged. Their camera worked fine.

BRosser314 14-03-2006 09:08

Re: anyother robots smoke up?
 
Quote:

Originally Posted by DjAlamose
This is what I have been told:
The camera wire somehow shorted out and caused an arc that caught their nylon fabric stuff on fire. The fire went out quickly but it still smoldered inside the electrical box. When they lifted up the cover they released the magic cloud. After they got back to their pits everything was fine and nothing (except the fabric) was damaged. Their camera worked fine.

Our pits were right next to them and they were examining there anderson battery connector. I believe that there connector was lose and the leads started to touch and after a while everyone knows there is the mysterious electrical smoke. When they brought it back to the pits they had to replace a connecter or just pop it back into place. Everyone thing was smoked and chared but i believe they had pretty good luck throughtout the weekend. :)

Richsgt 14-03-2006 10:07

Re: anyother robots smoke up?
 
We've smoked 2 of the fisher price motors so far this year, expecting at least one or 2 more before its all over. They're running the roller system full out so anytime we get a jam they tend to overheat fairly quickly, no flames.... but just a smokey burning smell.

pyro20911d 14-03-2006 11:11

Re: anyother robots smoke up?
 
I have a request for everyone who views this: Please post your videos in a text format.

Chrispy393 14-03-2006 11:38

Re: anyother robots smoke up?
 
Hurray for Magic Smoke. Just kidding, but those of you who did start smoking....you should have covered it up with a casual "Man, the fireworks weren't supposed to start until after we won!" Good luck and try to stay away from future ms. ;)

ICE MAN 14-03-2006 11:56

Re: anyother robots smoke up?
 
Last year at Nat's. a nut fell between our Victor 884s and landed on one of them. Then the nut made a circuit between the two motor out leads.Then the victor released puffs of smoke that the judge noticed and alerted our team. The result was a burned out victor that would only allow the motors to run forward and not back wards. :mad: This incident set us back the whole day.

KenWittlief 14-03-2006 11:58

Re: anyother robots smoke up?
 
The correct expression when an engineer makes a mistake, and something bad happens is "THERE!" (instead of "OOPS!")

as in 'There! That should do it!'

to the tune of America -Simon & Garfunkel

Toss me a speed control
I think theres one in my raincoat
We smoked the last one an hour ago
...


The magic smoke song every EE knows:
to the tune of Smoke on the Water - Deep Purple

Slow talking Walter
The fire engine guy
Slow talking Walt-er
nert nert nert
nert nert NER NERT!

...

^ dont you think every event should have this song queued and ready to play when a robot starts a motor meltdown?

Talos 14-03-2006 12:45

Re: anyother robots smoke up?
 
This is the electronics team captain from team 1189.

What I believe happened to our robot was that the PWM cable powering the camera was placed very close to the pins that connected the camera to its PCB. Unfortunately for us, there was a lot of heat from the power connection in the area, and our design didn't vent the camera very well. The heat melted the coating on the power PWM to the camera, and the exposed wire shorted on one of the screws that mounted the camera to the backplate. Essentially, the chassis became our ground, and the power load through the wire spiked, burning the whole wire along a 4-foot length. Literally the entire black wire was melted. Honestly, it was hard to determine where the power spike came from, as the cable was damaged badly enough that we couldn't tell much. It's also possible that the cable was pinched in a corner of our battery box, and touched one of the terminals, but I would think that would leave one, heavily damaged area, which I didn't find. The damage was well-spread over the entirety of the cable.

Fortunately, the cable couldn't have burned very long; no more than two or three seconds, but the plastic did smolder for along time afterward, and the smell was very potent. Our camera PCB was cracked from the heat, and we had to pull out the cable and replace it, but we've had no problems so far. Other cameras seem to be having similar issues with high heat near power connections. If this can be confirmed, it's definitely something that should be addressed in next year's kit.

Overall, we had a terrible regional, ranking 35th out of 63. Out of six matches, we were only fully operational for four, but I'm happy to say that, aside from the camera, we had literally no electronic faults. Mechanical and programming issues crippled us, but we hope to be up and swinging at the Waterloo Regional in Ontario.

KenWittlief 14-03-2006 12:54

Re: anyother robots smoke up?
 
If this is true, if the camera can get hot enough to melt the end of the PWM wires then it should be verified and guildlines for camera ventilation established.

The insulation melting the whole length of the wire doesnt surprize me. That sounds like there was an over current condtion (in the camera, or a short in the wire near the camera). The same current flows in the whole length of the cable, so if any part of its going to melt, its going to melt over its entire length.


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