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Unread 11-12-2014, 16:59
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FRC #1718 (The Fighting Pi)
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Re: Keeping the main breaker from tripping

Quote:
Originally Posted by Al Skierkiewicz View Post
I would agree that a permanent solution to cooling (keeping the breaker below ambient) the internal temperature of the breaker would be a violation of safety protection for which the breaker is ultimately designed.
The breakers on the robot are intended to prevent fires due to high current in any circuit on the robot. The wiring from the battery to the main breaker is the only circuit not protected. All breakers are meant to protect the wiring for this reason, not the load. The current rating vs. wire size is a derivative of the NEC specifications for open frame wiring. We slightly derate the tables based on the short time in use. These are not continuous (24 hour) currents. Even with the protection, we sometimes do see fires or at least significant smoke events all the time.
While we are on the subject, if you remove a motor(s) but leave the wiring, you must remove the breaker feeding that branch. (Consider this a 'best practice" method.)
That's right up there with always making sure you have female pwms on both ends of the wires connected to the digital sidecar, roborio, etc. It prevents someone from unplugging a wire from a motor or sensor and accidentally shorting the power pin to ground. I've always assumed that's the same reason the prongs always go into your wall at home, but never verified it.