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Unread 19-07-2011, 09:58
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
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Re: Measuring motor current (anyone tried this?)

As a caveat, the resistance across the 120 amp breaker varies with temperature and manufacture. A one foot length of #10 wire is very close to 1 milliohm. Placed in the power return at the input of a speed controller allows one to measure input current, of constant polarity, at 1mV/A. Sample at 500 Hz or higher and throw away measurements that are less than 20mV and you will get a pretty good idea what the current is.
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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.