by JussiH » Wed Oct 10, 2012 12:43 pm
The ESC32 calibrations serves two purposes: To calibrate the virtual current limiter and feed forward terms for closed loop mode. Closed loop mode is at the moment really only relevant for L1 control, but the virtual current limiter can be used regardless of the mode of the ESC.
It is always an advantage to calibrate the currentlimiter to your exact motor/prop combination, but its not mandatory.
Consider that the current limiters main job is to handle the spikes that occur during large ramps up in speed or if the motor fails. Its the ramping of throttle that casues the highest power surges, so having a strategy to limit/smooth them are crucial in any ESC. The default method uses a PI controller, but if you calibrate the CL term, then the ESC can predict what the current demand is for a certain throttle demand and allow to reach it faster than the PI controller will allow.
If using the default current limiter, then the advice is to set the currentlimiter about 10-20 percent higher than the highest current the motor will draw when ramped to full. So if your motor/prop pulls a maximum of 12A, then you set the current limiter to 13-15A. This means you get overhead for bursts, but the ESC can still limit current in case of a lockup or other motor failure.
Disabling the current limiter is a bad idea! In case a motor fails in flight it will allow that ESC and motor to draw as much current as your harness and battery will let it. Burning wires, motors and battery could be the immediate result - and if one ESC is allowed to draw max current, it can possibly brownout the battery before something burns out thus making the other motors and the FC struggle or fail.
If the current limiter is set correctly, it will only limit the huge spikes that comes from large and fast ramps of throttle, and you wont notice it.