How Victors deal with Back EMF, and current from the Motors.

[Generalx5]

I know that the MOSFETS on the victors have a Diode built into them. These diodes prevent Current from going backwards, but there is a limit to how much (I) is allowed anyone know, as for voltage, I think there is a high voltage protection built in as well.

Are there any electronically controled protection in the Victors? Are are the MOSFETS themselfs good enough to do the job?

If a Mosfet is not conducting and I apply a reverse current, will it be alright?

And theres this other thing that happends, when We push the robot around when its powered off, the Victors are able to turn on....from the power generated by the motors. But how is that possible? More in terms of the Victor and its insides.

[Al Skierkiewicz]

John,
The diode in the MOSFET is a fall out of the manufacturing process. You can review the data sheet for an IRL3103 and get all of the pertinent info there. Remember that the Victor uses three of these devices in parallel in each leg of an "H" bridge, for a total of 12 FETs. Only six are turned on at a time during operation. Each device is conservatively rated at 45 amps but can handle much higher currents at room temps. They are also designed for 30 volt drain to source voltage. However the Vitor itself is designed for 12 volt operation only. When you push a robot, the current path is through the diodes in the FETs (which act as a bridge rectifier) and back out to the power input of the Victor. This gives power to the Victor LED and other devices connected to the main power supply. There is an electrolytic capacitor across the power supply internal to the Victor. You can see it nestled inside the 12 FETs. Other than that, I don't remember there being any voltage clamp device in the Victor.

[RyanN]

The only voltage clamp built into the victor is when it starts to smoke...

[Generalx5]

I guess not eh...