View Single Post
  #66   Spotlight this post!  
Unread 15-03-2009, 13:40
jerry w's Avatar
jerry w jerry w is offline
Free Agent Mentor
no team (Team Krunch)
Team Role: Engineer
 
Join Date: Nov 2003
Rookie Year: 2002
Location: dunedin fl
Posts: 113
jerry w has much to be proud ofjerry w has much to be proud ofjerry w has much to be proud ofjerry w has much to be proud ofjerry w has much to be proud ofjerry w has much to be proud ofjerry w has much to be proud ofjerry w has much to be proud ofjerry w has much to be proud of
Re: possible solution to the static problem

Quote:
Originally Posted by Al Skierkiewicz View Post
The regolith is also nonconductive. I would put it's voltage standoff rating in the tens of Kv range or better. Maybe I am missing something here, but I don't see how a drag chain could have any additional effect. When you use a drag chain over concrete, the material is conductive to some extent and likewise for carpet depending on the humidity and moisture content of the materials. The regolith is adverse to moisture absoption so it's electrical properties should not change over a weekend.
Let's not forget surface charges. As a material collects charge of a certain polarity, that charge spreads over the surface of the material. The chain brings the opposite charge down to the surface. This allows a restoration over time. Since the buildup occurs over time as well, we have an equalizing effect. The difference in charges will never become large.

Now that the trailers are using a drag chain, I would expect to see no large buildup on the playing field. However, the practice field remains a problem. The trailers on the practice field had no chain. Also, robots on this field have a tether cable attached. If charges are allowed to build, the driver station is subject to potential damage. an arc to the tether from robot frame is likely. the driver station has only minimal esd protection.

I have not heard credible evidence about cRIO damage. So far, there is evidence of only driver stations that have failed. I have seen and heard of only damage to driver stations and analog breakout modules. Other comments, here and elsewhere, have lumped the system failure as a cRIO failure. Please understand, i think WPI did a very good job of making a cRIO based system. it is simply not as rugged as the NI equipment.

(Also, spraying the wheels may work, but is against the rules. This lubricant changes the traction of the wheel.)

jerry
__________________
Happiest when people tell the truth... However, I am blessed with many friends.