Powering the speed controller outputs


Powering a motor wired to a speed controller from the two output screws with a battery + alligator clips.

I will be running the motor directly to a battery through the screws+terminal on the speed controller.

Does anyone know if this would damage the speed controller in anyway? Having power run into the output terminals on the speed controller?

This is being done to shift some motors powering a winch.

Is this a Victor or a Jaguar?

I’ve never tried it with a Jaguar, but can tell you things like this happen all the time. Every time you backdrive a motor, the back-emf’s generated by it will power the speed controller. That means, when you push your robot across the floor, you are backfeeding power into your speed controllers. They should be able handle it. I would hope this is not your method for removing the robot from the bar, as this would probably not be legal, since <r20> requires robots to not be powered up when removing them from the tower.

Careful! We did this in the offseason to test some motors, and we ended up with two burned out Jaguars. I’m not an electrical person; I can’t explain why. All I know is that we fried 'em. That was a very expensive lesson for us.

Under the rules you may not affect a motor with a custom circuit, which is what it sounds like you are asking. If you are asking if you can add something in parallel with the output side of the controller you cannot do that on a competition robot. In general practice, the speed controller is not protected from changes in the load side power. Damage to the controller is likely, almost a guarantee.

This will not be used in the field, and this is something to be done in the pits. We want to be able to reset the winch system without turning the whole control system on.

Is it really that big of a deal to turn the system on and wait a few moments at the same time checking out the rest of your robot thus not worrying about damaging any component of your robot?

The winch system needs to be reset once we bring it into the pits. Turning the whole control system on takes up more time.

Here is a radical idea for you. Use some Power Lock connectors between the controller and the motor. Then simply disconnect the motor connector and insert a power device of your choosing to rewind the motor. We have taken a 12 volt battery operated drill and added external wires with Power Locks on them to test motors and reset motor operated devices in the past.

Great solution! I’ve seen this done in the pits (by team 192) and I thought it was the neatest thing ever.

We use the Anderson PowerPole series for these connections - you can see them here - they’re the blue connectors. It’s pretty easy from this to plug a battery straight in, or even to just take the lead from the PDB and stick it in the lead form the motor for a quick short cut with a powered on robot.

Just remember to use some kind of protection device (fuse, breaker) between your power source (likely a battery) and the motor, as close to the battery as practical. It can really ruin your day when a battery output gets a short circuit and all that’s protecting it is a piece of #6 wire. ::safety::