Thread: Victor qeustion
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Unread 22-04-2004, 14:46
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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
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Re: Victor qeustion

Don't be mislead by the lights...
Victors will light if there is no power applied and you push the robot thereby spinning the motors and and generating reverse currents to a device that is not turned on(this is only when the brake jumper is in coast, I think). If the Victor is powered and is receiving a 127 from the RC then the brake jumper will determine what the output connection of the Victor will do. If the jumper is in coast, the output is essentially open circuit (all FETs are OFF)) if the jumper is in brake then the the output is shorted (all FETs in the negative side of the bridge will be ON). While powered, current may only return to the battery through the Victor during the time the FETs are switched on and then only if the generated voltage from the motor exceeds the battery voltage plus the voltage drops in the wiring and the FETs.
In the case of two motors on a common output shaft, the undriven motor should be in "coast" else the load on the drivetrain will be extreme. The "brake" mode will act as an additional mechanical/electrical load on the drivetrain and speed will decrease and current consumption will increase.
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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.

Last edited by Al Skierkiewicz : 22-04-2004 at 14:50.