View Single Post
  #9   Spotlight this post!  
Unread 04-02-2005, 07:30
Unsung FIRST Hero
Al Skierkiewicz Al Skierkiewicz is offline
Broadcast Eng/Chief Robot Inspector
AKA: Big Al WFFA 2005
FRC #0111 (WildStang)
Team Role: Engineer
 
Join Date: Jun 2001
Rookie Year: 1996
Location: Wheeling, IL
Posts: 10,770
Al Skierkiewicz has a reputation beyond reputeAl Skierkiewicz has a reputation beyond reputeAl Skierkiewicz has a reputation beyond reputeAl Skierkiewicz has a reputation beyond reputeAl Skierkiewicz has a reputation beyond reputeAl Skierkiewicz has a reputation beyond reputeAl Skierkiewicz has a reputation beyond reputeAl Skierkiewicz has a reputation beyond reputeAl Skierkiewicz has a reputation beyond reputeAl Skierkiewicz has a reputation beyond reputeAl Skierkiewicz has a reputation beyond repute
Re: Blown Victors - WHY?

Quote:
Originally Posted by roboticsjenkins
They blew because you probably grounded the Victors out because I had that problem last year. It's better to mount them on a piece of material that is not a conductor of electricity......Thats my guess
Andrew,
The case of the Victors is an insulator. We mount our electricals on a punched aluminum sheet and have never had a problem.

"From DigiKey: IRL3103-ND"
It is really interesting if you take a look at the data sheet on these little gems. http://www.irf.com/product-info/data...ta/irl3103.pdf Note under maximum ratings, that continuous current is 64 amps and pulsed current is 220 amps per device (limited by junction temperature). Remember that there are three devices in parallel for 64 x 3=192 amps as long as you can keep the little buggers cool. When teams blow these up, there is some extreme abuse occuring. High currents over long periods of time, heat and/or metal flakes in of near the devices spell destruction. Changing FETs is not a guaranteed fix, other devices may be destroyed when a FET(s) short.
Please note that the Drain and the tab of the package are connected together. That means that the tabs of half of the FETs in the victor are connected to battery positive and the tabs of the other half are connected to motor positive. Keep conductive material away from the FETs.
__________________
Good Luck All. Learn something new, everyday!
Al
WB9UVJ
www.wildstang.org
________________________
Storming the Tower since 1996.

Last edited by Al Skierkiewicz : 04-02-2005 at 07:45.