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Unread 26-02-2013, 15:26
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Jon Stratis Jon Stratis is offline
Electrical/Programming Mentor
FRC #2177 (The Robettes)
Team Role: Mentor
 
Join Date: Feb 2007
Rookie Year: 2006
Location: Minnesota
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Re: Power Distibution Board - Broken stud

The PDB was introduced in 2009 for Lunacy, if I remember correctly. Since then, we've only had to buy one replacement a couple of years ago, for a board that got burned out after being mis-wired. We've never had any of the studs on our boards break off.

Now, for our story this year on a broken PDB:

This year, we're using an old board. About 4PM the day we bagged the robot one of our mechanical guys wanted to run a motor manually - we have a rig set up that allows us to safely (this part can't be emphasized enough for teams that want to do something similar!) do this with our Anderson PowerPole connectors, and it even has variable speed control! Anyways, when the mentor went to power the motor, he plugged into the wrong side of the PowerPole connectors, feeding 12V into the PDB through the Wago connectors while the robot was turned off. When they powered on the robot, there were a lot of red LEDs on the PDB and stuff didn't work.

While all this was happening, I was in the car heading to the build space from work. I got a phone call from the guilty mentor that started with "I think I did something very bad..." After getting the full description of what he was seeing, I told him the board needed to be replaced with one of our old "spares". Seemingly at the same time, the electrical team came to the same conclusion after doing some searching on CD.

So, take this lesson to heart: mechanical mentors should never touch anything electrical!


Anyways, what I'm getting at is you're seeing a 50% failure rate, but most teams aren't. My team hasn't seen any failures that we didn't directly cause through misuse. If there really were that many failures of the studs across all FIRST teams, we would have heard a lot more about it than the occasional breakage we hear about now.
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