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Freeze spray never allows significantly more current to pass through the breaker. It should be noted that every time the breaker trips it is easier to trip the next time. Freeze spray can help to get the breaker back to normal, in other words it will trip as if it was new or close to it. Last year, the breaker problems became more apparent than in past years. We had a breaker that took only a slight tap with a screw driver to trip it because it had tripped so many times. While I know this thread was designated for design strategies, there are several tricks you should use around the breaker that we learned last year.
1. The freeze spray does work. We used it a lot last year.
2. Mount it loosely and orient it in a way that the switch is not in line with the most likely collision direction.
3. If a breaker has tripped several times, replace it. Especially do this if you have many matches left to play.
4. Don't use the breaker as a switch. These breakers aren't switch rated, and by using as a switch it subsequently is easier to trip. Turn the robot off by unplugging the battery cable.
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Are you talking about the main 60 A breaker or the mini-30A breakers?
BTW, if people are worrying about shock to their breakers, why not use the vibration isolation mounts provided by Small parts to mount them? (Or equivalent product available from this year's legitimate supplier)
Last year, we routinely tripped our 30A breakers on our main drive motor. However, that occurred due to a design flaw in our gear box. The tolerances were too tight and we were machining grooves in our rotating parts. Once diagnosed and fixed (in the off season), we have beaten the heck out of our robot with no breaker trips.
On our first robot (2000), we used a lag algorithm on the joystick to avoid the maximum acceleration at zero speed issue.
In 2001, we picked a gear ratio which seemed to keep us in the "sweet spot" on the torque-current curve. That robot runs cool under all circumstances. Although it is not as fast as we would like.
For future reference, we bought a bunch of 30A breakers from innovation first. Our plan is, when they start popping, replace them. Now that we know about freeze spray, we'll probably incorporate both forced cooling of the breakers (we already do this with our drive motors) and a blast of freeze spray at the start of a match.
As for driver instructions and software over-rides, I think that is a function of your drive team. In general, we prefer to give the driver the ability to push the robot as far out on the performance envelope as he feels necessary. However, we have had operators who needed some software limits to keep from breaking things.
Usually during the course of the competition, we try to customize the controls around the driver's/operator's preferences.
During the off season, we have all kinds of limits which we impose, since we use a lot of untrained drivers.
A question for the breaker gurus...
In 2002, we were running both Chalupas at full blast for the full two minutes + both drill motors at close to their limits + a globe motor + two seat motors + one fischer price motor intermittantly. We never tripped the 60 A breaker. We did mount the breaker switch perpendicular to our direction of travel.
For teams that tripped the 60A breaker, what kind of loads were you putting on your system? Was the breaker trip more shock related than electrical?
Andrew
Team 356