Hi Adam,
We are planning to mount 5 Basic ESC to a single metallic plate for heatsinking purposes. I was wondering if one of the ESC fails (opens or shorts), could it impose the voltage on other ESCs on the plate?
What is the failure mode of the ESC, how do they fail?
If an ESC fails short with the main power you’ll likely be much more concerned about the battery/power supply than the other ESCs. If the signal lines get shorted then the only risk for the other ESCs and electronics is undervoltage and a struggling power regulator, which isn’t great but shouldn’t cause major damage unless the ROV is in a sensitive location and floats/sinks into something it shouldn’t.
They’re quite robust, especially if kept within their specified operating range, and in the rare case of a failure it’s most likely to be something failing open, which just means that thruster will stop working. As a useful safety protocol, it’s worth regularly doing a quick motor check through QGC (ideally before each dive), so you can stop potential issues before they have a chance to become more serious.
You also tend to notice a non-functioning thruster pretty quickly if you’re using manual control - it throws the dynamics off quite a bit, and is much more rotatey than you get from just strong current or a tether snag.