pic: ummm......what?

[Alex Cormier]

Originally Posted by EricH

So how did you shut the robot off afterwards?

Unplug the battery?

[MikeE]

I'm going to take a wild guess that it probably won't pass inspection in St Louis as-is.

[EricH]

Unplugging the battery when the circuit is on carries a risk of sparks, guys. I would not suggest trying that--ANYWHERE. That's why I asked.

[Travis Hoffman]

Just blame it on us. We looked at it funny in the semifinals.

[IndySam]

Originally Posted by Travis Hoffman

Just blame it on us. We looked at it funny in the semifinals.

Travis is a jinks! You should have seen what he did to us at SMR!

[Travis Hoffman]

Originally Posted by IndySam

Travis is a jinks! You should have seen what he did to us at SMR!

Maybe the Force is with me? I do hang around with people like this, after all (the one without the ponytail...wait the Storm Trooper is a girl...I'm pretty sure she had a ponytail too...um, the one without the moustache, then).

Instead of external shock causing damage, what about something internal/structural causing the breakage?

[ATannahill]

Originally Posted by EricH

Unplugging the battery when the circuit is on carries a risk of sparks, guys. I would not suggest trying that--ANYWHERE. That's why I asked.

What would you suggest in that situation?

[EricH]

Originally Posted by rtfgnow

What would you suggest in that situation?

I would suggest a non-conductive poke stick to separate the contacts on the main breaker. Normally, that non-conductive poke stick is the red button. Separate the contacts, then yank the battery, then pull and replace the breaker. In this case, poke on that upper tab-type thing to break connection is where I'd go for first.

I've seen the sparks that can fly when there's marginal contact on a battery to some other connection (charger, bolt, other battery). They may look pretty, but you don't want to see them because they mean something's wrong.

[David Dawson]

Originally Posted by EricH

I would suggest a non-conductive poke stick to separate the contacts on the main breaker. Normally, that non-conductive poke stick is the red button. Separate the contacts, then yank the battery, then pull and replace the breaker. In this case, poke on that upper tab-type thing to break connection is where I'd go for first.

I've seen the sparks that can fly when there's marginal contact on a battery to some other connection (charger, bolt, other battery). They may look pretty, but you don't want to see them because they mean something's wrong.

I have never seen sparks emit from a live Anderson connector. And Ive seen them used to jump start cars. Safety doesn't mean find the hardest way to do something.

[Chris is me]

Originally Posted by EricH

I would suggest a non-conductive poke stick to separate the contacts on the main breaker. Normally, that non-conductive poke stick is the red button. Separate the contacts, then yank the battery, then pull and replace the breaker. In this case, poke on that upper tab-type thing to break connection is where I'd go for first.

I've seen the sparks that can fly when there's marginal contact on a battery to some other connection (charger, bolt, other battery). They may look pretty, but you don't want to see them because they mean something's wrong.

And you don't think there's a greater chance that poking a fuse with a stick will unintentionally cause a short than unplugging an Anderson connector?

[EricH]

Originally Posted by David Dawson

I have never seen sparks emit from a live Anderson connector. And Ive seen them used to jump start cars. Safety doesn't mean find the hardest way to do something.

I've seen a plugged-in FRC battery spark. I forget whether it was the Anderson or the terminals, but I seem to recall that the area around the Anderson fused (read: welded) to something else before someone could get in there and separate the battery from whatever it was connected to (thankfully, not a robot in that case).


Chris, the thing about using a non-conductive poke stick on the connector is that 1) you only get one place for a spark (the breaker, which in this case is already broken) as opposed to 2 (each side of the Anderson) and 2) your hands are not right there to risk getting zapped.

I don't know about you guys, but I'm not sure I'd want my hands right next to a fully-live FRC battery's current and voltage if I had to unplug it, even with an Anderson connector between my hands and the wires. (By fully-live, I mean current is flowing actively, not current can flow if the connection is made.)

[David Dawson]

Originally Posted by EricH

I've seen a plugged-in FRC battery spark. I forget whether it was the Anderson or the terminals, but I seem to recall that the area around the Anderson fused (read: welded) to something else before someone could get in there and separate the battery from whatever it was connected to (thankfully, not a robot in that case).

What you just described wasn't a Anderson short circuit. If two power poles fused together a wire had a short or the system drew too much current. Anderson terminals are designed for safety and useability which is why they have shielded contacts. If you really want to get technical even if there was a slight spark between the power poles it would take the path of least resistance (i.e not your hand) for the milliseconds it would have before the connectors were far enough apart. I would take my chances with this before touching a broken exposed circuit breaker.

[Andy A.]

Under the circumstances, disconnecting the battery would have been the safest thing. The priority should be to depower the robot, and the very busted up breaker, ASAP.

While not good practice, breaking the connection at the Anderson while the robot is 'live' isn't particularly hazardous to operator or robot. By design, any arcing will occur while the Anderson is still enclosed. So while it may score the contacts a bit, that's the worse case scenario. As long as it's not an every day occurrence you won't notice.

[EricH]

David, IIRC, it was some form of short circuit. It's been a few years, but it was in a row of batteries that were charging. I looked around to see several people rush over to try to figure out how to disconnect the battery that was throwing sparks. Like I said, it's been a few years, so I forget the details like what exactly fused to what.

Also, I never said to touch the circuit breaker with your hand. I said to use an insulated poke stick. That way, there is zero chance that electricity goes to your hand.

[Andrew Y.]

eric, thanks for your point of view...but my professional experience and my advisors at work all agree my kids took the correct action by unplugging the battery...even the OSHA dude at work agrees...and him and i NEVER agree.