Chief Delphi - Weird issue with the power distribution block

Chief Delphi (http://www.chiefdelphi.com/forums/index.php)

- Electrical (http://www.chiefdelphi.com/forums/forumdisplay.php?f=53)

- - Weird issue with the power distribution block (http://www.chiefdelphi.com/forums/showthread.php?t=74724)

Re: Weird issue with the power distribution block

Just so that we don't confuse anyone, the diodes are speced at 1V@20 amps and 1.25V@40 amps each when forward biased. So even if you could drive the motors at full RPM (highly doubtful) then the diodes would drop at least 2 volts in the speed controller. Remember that the bridge would have two diodes in series with the power supply input pins plus the 0.0005 ohm resistor in the Jaguar negative lead plus the wiring resistance. It is unlikely that you could provide enough power to light up the power convertors for the Crio but you might. Just not long enough for any of the system to boot.

Re: Weird issue with the power distribution block

Quote:

Originally Posted by Al Skierkiewicz (Post 823865)

When you push a robot, the motors begin to act like a generator. The speed controllers (both Victors and Jaguars) use power FETs that have a diode internal to the devices. As you generate current in the motors, that current forward biases the diodes in the FETs and since they are in a bridge configuration, power is back fed to the electrical system. There is no way you can generate enough current to back feed a full 12 volts to the system, but you can generate enough to light some LEDs and make it look like you have an electrical problem. All of this is normal.

odd, we've gotten ALL SYSTEMS to boot up while pushing the bot!

by that i mean, we had connection between the bot and DS without the battery being plugged in! the station read 12.24 volts at peak (which lasted about a minute)

needless to say, i was exhausted after pushing the robot that long.

-Z

Re: Weird issue with the power distribution block