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Unread 30-01-2016, 18:58
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Engineer at Medrobotics
AKA: Dr. Joe
FRC #0088 (TJ2)
Team Role: Engineer
 
Join Date: May 2001
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Re: Brown out / breaker trips with Pneumatic Tires

Quote:
Originally Posted by Chris Mounts View Post
We've swapped out the secondary reduction to put us at a total of 12.76:1 reduction. It's a double 14:50 gear setup.
2 CIMs per side, 8 inch Pnuematic (AndyMark) Tires, 12.76:1 ratio

JVN's sheet says ~12fps and ~70Amp per motor during a pushing match.

I would say you're probably playing with fire with that current in a pushing match number.

It's not surprising that you end up tripping breakers and possibly browning out (where the RoboRio protects itself by turning off motors).

I hate to say it but I fear this is the tip of the iceberg where the brown out protection that FIRST put into place last year doesn't actually end up keeping the important bits alive after all when robots have less than friendly interactions (aka any year except last year and that terrible 4vs0 year).

Back to your particular problem. I recommend you look into less grippy tires or more gear ratio. 3 CIMS would help but only so with the breakers tripping (they'd still trip but at 47Amps per motor you'd have a bit more time pushing) it wouldn't help with the brown out at all.

Keep us informed on your progress -- especially radio lock up issues.

Good luck,
Dr. Joe J.
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