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Unread 22-03-2006, 08:02
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Al Skierkiewicz Al Skierkiewicz is offline
Broadcast Eng/Chief Robot Inspector
AKA: Big Al WFFA 2005
FRC #0111 (WildStang)
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Re: 2005 Electricals or 2006?

Quote:
Originally Posted by Gary Dillard
We used the 2005 at my request - clean, compact, light. I loved it when it came out. Didn't use the diagnostics.

I have a couple questions, however:

2) Likewise, isn't ground ground?
Gary, Gary, Gary. This isn't ground, although many people call it that (ground is what you walk on). This is the return side of the battery and should be treated just like the supply side.
I would modify the IFI statement by saying power to the RC should be from the 1 or 2 position and then follow the IFI recomendations for any additional outputs. You can visualize the current path within the box from where the input terminals are located. Since everything has some resistance, high current items will draw current through this resistance causing a voltage drop across the resistance. The high current outputs (40 amp) are above the input terminal and will drop voltage from the terminal to each output while minimally affecting the lower current outputs. Anything that draws current from the lower current outputs will also drop voltage from the input terminal to the output. That is why I recommend that the RC be powered from the position that will have the least voltage drop/closest to the input terminal. If you look at the board you will see that the return terminals are also numbered so that they roughly correspond to the current path the supply side takes to minimize loss. The RC is the most voltage sensitive device in our system, cutting out when the input voltage falls below about 8 volts. By putting the power closest to the battery inputs allows a minimal drop during current spikes and lets you play longer and harder.
As to the wire length question, the breaker panel has all robot current concentrated in one device while wiring is carrying current to individual devices. The amount of current that flows through the panel is the same current flowing through the battery and at full charge that could be well over 400 amps. Ohm's Law cuts in where V=I*R, so if you keep R constant and increase I the voltage also increases. #10 wire is .001 ohms per foot but I bet the panel is about one tenth of that or less.
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Good Luck All. Learn something new, everyday!
Al
WB9UVJ
www.wildstang.org
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Storming the Tower since 1996.