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Unread 19-07-2011, 11:54
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Programmer and Mentor
AKA: Mike Aalderink
FRC #3458 (Code Blue)
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Re: Measuring motor current (anyone tried this?)

Quote:
Originally Posted by Al Skierkiewicz View Post
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.
Al,

I have seen you say this a few times and I am now wondering, do I just leave the 1 foot of wire straight, should I wrap it around something like a screwdriver handle to take up space? I am thinking about setting up something for 2012 where we can monitor our motors a little better as I have gotten better with programming.

-Mike