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Unread 12-09-2014, 15:51
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BBray_T1296 BBray_T1296 is offline
I am Dave! Yognaut
AKA: Brian Bray
FRC #1296 (Full Metal Jackets)
Team Role: Mentor
 
Join Date: Jan 2011
Rookie Year: 2010
Location: Rockwall, TX
Posts: 947
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Re: Experience With 6 Cim Drive train

Our robot used 6 Cims this year. We used VexPro Ball shifters with total reduction being 5.5fps and 15.5fps. (<- not sure if accounting for inefficiencies). Our Drivetrain setup was a 6wd tank drive with 3" Colson wheels and non-cantilevered axles. It is worth noting our center of gravity was within 5" of the floor.

We played extensive defense all year. We tripped the breaker one single time all year, and that was playing at Texas Robot Roundup after 2 regionals, and a prior off-season event. During the season, we had absolutely no breaker problems.

I will try to dig up some video, if you would like.

For your questions.
-The battery was a few degrees above room temperature, the plastic casing was no hotter that a battery just off the charger. (When swapping robot batteries there was no thermal way of telling them apart from the casing)
-Our battery terminals are heat-shrinked and taped up so the metal itself is untouchable. I will say the whole lead assembly from the battery to the PDB was significantly warm, but you could comfortably leave your hand on them.
-We have never had any issues related to the battery connector, and, like I just said, these were also warm but not concerning.

We did not have any form of cooling; no sinks, no fans. After a match the back of the motor (where the brushes are) was too hot to touch for more than a second, but the rest was ok. (By the next match the heat had mostly dissipated). I think we will seriously consider some form of thermal dissipation in the future. We may put one of the large computer fans on the bunch of 3, or make our own heat sink. We do not find the heat sink the KOP had particularly useful, because like I said, it is the back of the motor that needs cooling, not the main casing. While those would help, the heat does not propagate that far to make them useful in my experienced opinion.

We did practice our robot for about 2 hours straight, with nothing but some 30 second battery changes every 5 minutes. By the end, you could easily boil water with those things, they were roasting.
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If molecular reactions are deterministic, are all universes identical?

RIP David Shafer: you will be missed



Last edited by BBray_T1296 : 12-09-2014 at 16:07.