a little over a year ago, I posted a question on the forums, asking about the “safe” number of 393 motors (6), and I thank everybody for the info i received on the subject. So, as I understand it, If I used a power expander, I could put 4 393’s on the cortex (two between 1-5 and two between 6-10) and two 393’s on the power expander. BUT I heard of teams using 8-10 of them during the Sack Attack season.
The question is this:
How many 393’s do you plan to use during the Toss Up season?
If you have a power expander, there’s almost no reason not to be using all 10 393 motors; if you have leftover motors when designing your robot, put them on a crucial system as backup/extra power; drive power or hang power will come in handy.
Last year we had a claw that used 2 393 motors on a power expander. We had only these 2 motors on the expander so when the breaker did trip, the it would only take out our claw, and not the rest of our robot.
We’re going to use 8 or 10 this year, depends on if the intake needs them or not. Last year we used 10 with no issues and had a power expander.
This year to save weight, we plan on going without the power expander and will have to see how the cortex holds up, but any issues will likely be end user error, for example stalling out the drive in a pushing match.
One of the tricks we employ is putting half of the motors from each subsystem (drive/lift) onto each circuit breaker so you split your pull of current.
We used all 10 393s, 6 on the cortex and 4 on the power expander. Our drive was 6 motors, so we put the arm on the power expander. We didn’t have any problems, except when we got into pushing matches against heavier robots, which is likely not a good idea under any motor setup.
Last year we used eight 393s without a power expander. No clue if that’s the reason why we had connection issues, but when it was tethered, the robot worked fine. This year we would like to use 10, however it looks like we’re going for either 7 or 9