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Unread 06-04-2009, 09:15
Unsung FIRST Hero
Al Skierkiewicz Al Skierkiewicz is offline
Broadcast Eng/Chief Robot Inspector
AKA: Big Al WFFA 2005
FRC #0111 (WildStang)
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Re: Victor Vs Jaguar

Avery,
All things being equal, the output of the controllers coupled to a motor are controlling current within the motor. Current translates to speed. So the things that limit this current is the "on" time of the controller and all series resistances between the battery and the motor. Assuming the controller is at full throttle then the battery is effectively connected directly to the motor through the controller. The series resistances are the wiring (.0005 ohm/ft for #6, .001 ohm/ft for #10, .002 ohm/ft for #12) the series resistance of the connections (usually much less than .0005 ohms total for 5-10 connections) the .0005 ohm resistor in the Jaguar, and the series resistance of the FETs. Remember that the FETs are in groups of three in parallel and there are two groups in series at any one time. For the Victor this is 12 mohm per FET or 4mohm per group or 8mohm (.008 ohms) per Victor. The Jaguar is 5.2mohm per device or 1.8mohm per group for 3.5 mohm per controller + 0.5 mohm for the current sense resistor=4mohm or 0.004 ohms Jaguar. However, the Jaguar must add a short pulse to battery common at regular intervals to charge up the internal capacitor for driving the FETs. So the controller output is not at full throttle one hundred percent of the time but is very close.
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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.