View Single Post
  #3   Spotlight this post!  
Unread 17-02-2014, 16:59
Taylor Hawkins Taylor Hawkins is offline
2386 BCHS Trojans
FRC #2386 (Trojans)
Team Role: Mentor
 
Join Date: Jan 2011
Rookie Year: 2010
Location: Burlington Ontario Canada
Posts: 29
Taylor Hawkins is an unknown quantity at this point
Re: Electric Isolation

Quote:
Originally Posted by WolfBotics View Post
Greetings from team 5145!

As our team nears completion of our robot, we are currently reviewing the inspection checklist. Rule 37 states that the electrical system must be isolated from the frame, however, we have discovered that the robot frame is at the same potential as the ground on our battery. After further inspection, we discovered the source of this to be the screws holding the PD to the frame of the robot. Is this okay, or do we need to mount the PD on a non-metallic mounting surface, or use nylon screws? From a safety standpoint, we are not overly concerned, as the open circuit resistance between the positive power terminal and the frame is a couple hundred kohms. We just want to make sure we are in compliance with the rules.
Are you sure about the PD board being the problem? The usual culprits for this problem is that the cRIO frame is bonded to the negative terminal of the input leads. Usually the cRIO needs to be mounted on an electrically insulated platform (Plastic/ Wood). The other source could also be the camera. The stud that sticks out the back is also connected to the negative inside of the camera.(Not all but some models)

Just as an aside, did you drill out the mounting holes on the PD Board. Are team did that once on a practice bot and that allowed the frame to be accidentally connected to the negative terminal leaving the frame electrically conductive.