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Unread 22-10-2004, 08:34
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: 10,798
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Re: Mechanical tips for rookies

All,
The top of my list is to get a working/driving base finished first. It is needed for electrical to work on part placement, drive team needs practice and autonomous team needs something to mount prototypes on.
Open gear transmissions produce metal flakes (grindage) so protect electrical circuits from fallout.
Be aware of robot systems when drilling or machining parts on the bot. A square tube makes as good an electrical conduit as it does a support member. Your electrical team may have passed motor wiring through the tube you are drilling!
NO GRINDING IN THE PITS! Besides it causing incredible noise, the flying hot bits are a real fire hazard.
When a motor or other shaft does not have enough bearing (most do not) you must add bearings that can take the stress. You cannot hang a sprocket or wheel on the end of the chalupa motor shaft and expect it (the motor) to survive.
Motors do draw "stall current" when you stop them. Avoid stalling motors or running them in near stall in your designs. The currents are extreme and the motors will run very hot. Stall current on the drill motor is 129 Amps or over 1500 watts.
Grindage and flakes from ferrous metals are attracted to the magnets inside motors. This is a big concern for open frame motors like the drill and FP motors and fans, where the flakes will jamb between magnet and armature or short out the brush assembly or armature windings. Compressed air will not dislodge these flakes. The speed controllers are not sealed and many have died from metal flakes falling into them.
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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.