View Single Post
  #17   Spotlight this post!  
Unread 12-02-2009, 11:04
Alan Anderson's Avatar
Alan Anderson Alan Anderson is offline
Software Architect
FRC #0045 (TechnoKats)
Team Role: Mentor
 
Join Date: Feb 2004
Rookie Year: 2004
Location: Kokomo, Indiana
Posts: 9,113
Alan Anderson has a reputation beyond reputeAlan Anderson has a reputation beyond reputeAlan Anderson has a reputation beyond reputeAlan Anderson has a reputation beyond reputeAlan Anderson has a reputation beyond reputeAlan Anderson has a reputation beyond reputeAlan Anderson has a reputation beyond reputeAlan Anderson has a reputation beyond reputeAlan Anderson has a reputation beyond reputeAlan Anderson has a reputation beyond reputeAlan Anderson has a reputation beyond repute
Re: Solving static electricity problems by grounding the frame

Quote:
Originally Posted by ErichKeane View Post
I also still don't see how two colliding bots with grounded frames cause any issues. Attaching the ground wire from two batteries causes absolutely no problem.
Quote:
Originally Posted by EricVanWyk View Post
I don't either, I think this reason is simply wrong.
Two robots contacting only at the frames will not exhibit any issues. The potential for unwanted current flow happens if part of one robot accidentally touches a live circuit in another while the frames provide a current path. Isolating the frame removes the possibility of a single fault causing large electrical problems.

You can still get smoked wires if two things go wrong at the same time -- which the TechnoKats had happen (twice!) in the pits last year. One motor lead rubbed against an unnecessarily sharp corner and the conductor intermittently contacted the frame when the arm was being raised. A sensor wire was smashed between a drive motor and the pan at the bottom of the robot, with the ground wire intermittently contacting the frame when the robot was lifted from underneath. Drive the roller motor while the arm is moving up and the robot is in the pit on the cart -- and the AWG24 sensor ground wire gives its life trying to handle twenty amps.