motor stall current vs Victor ratings

[Tristan Lall]

Originally Posted by dawilliams

1. Are FIRST robots allowed more than one battery?

Yes, but not in the way you're thinking. Only one 12 V battery (of the Exide ES18-12 or EX18-12 types) and one 7.2 V battery (any NiCd pack) may be used as described in the rules.

Originally Posted by dawilliams

2. Can we have more than one main breaker in parallel off the battery (if only one is allowed)?

This one should be a no, per <R54>, but there's a little bit of a catch here. If you read <R54> as meaning "use these devices in this general arrangement," (there's a diagram) "but don't worry about making the connections in exactly this way", then you've probably satisfied the rule as it was intended to be followed. But the loophole is, of course, that a 120 A circuit breaker (even a 2^nd one) is a legal additional electrical part*. If you're reading the rule to mean that the connections don't have to be made in exactly this manner, then you have not restricted the nature of those connections in any meaningful way. You could therefore claim, that having two parallel 120 A breakers (in the usual place in the circuit) satisfies the diagram (because a subset of the electrical system is exactly as required, and the diagram does not preclude the possiblity of different or additional connections).

Now, to anyone who's been in FIRST a while, that's obviously not the expected conclusion—but how can we interpret the rule to make this configuration impossible? It seems to me that we would have to read the rule as meaning "use these devices in this exact arrangement, including making the specified connections". This, means that you must not add anything extraneous to, or remove anything from the specified portions of the circuit. All this is fine, until you run into the fact that the Maxi fuse panel and both ATC panels are in the circuit as drawn, and connected in a particular fashion. That implies that all must be present and connected exactly this way, even if not used. The Maxi block is heavy, and teams might understandably want to be rid of it, to make weight (sacrificing maximum power output in the process); similarly, it's likely that one of the ATC panels is redundant. The rule certainly wasn't interpreted and enforced according to this reasoning last year.

We could look for a middle ground (where the extra main breaker is illegal, but the rest of the diagram is less strictly defined), but no such thing was proposed during the season—indeed, it seems to have been overlooked by all.

I should note that depending on the circumstances, it may well be ruled as unsafe per se, and therefore in violation of <S01> and/or <R40> (which pertain to unsafe design, operation or additional part usage, as judged by referees and inspectors, respectively), but without direction in that regard, various officials will have different feelings on the matter, depending on their perspectives and knowledge. (And indeed, if the parallel arrangement is unsafe, consider that the very same reasoning might lead a single 120 A breaker to also be considered unsafe—I can think of some arguments which might lead down this road....)

I don't recommend trying to exploit this potential loophole, as it would probably be quashed very quickly upon being submitted to the Q&A.

Originally Posted by dawilliams

3. Are the circuit breakers provided in the KOP auto resetting? Main breaker auto resetting?

The individual 20, 30 and 40 A breakers are self-resetting; the 120 A main breaker is not.

All of the preceding applies to the 2006 game, and may not be true in 2007.

*It is legal to have on your robot (and not just as a decoration), because it satisfies the additional electronics rules and is not specifically prohibited anywhere. Its precise function (beyond its mere presence) is the issue.