At rest (learn mode ON) the gearhead servo is 81 degrees Fahrenheit . Running a sequence which uses base, shoulder and elbow lift (but no elbow rotation) for 2 minutes raises the gearhead servo to 104 degrees Fahrenheit. The shoulder rises only to 97 and the elbow to only 90.
104°F corresponds to 40°C. 40°C is a normal value for this motor and it’s far from the limit value. Note that if a motor becomes too hot, it will not work correctly but won’t be damaged, you’ll just have to wait until it cools down.
Also, yes all the motors do not have equal heat, so that’s normal too.
About your last point: indeed it could be interesting to power on the fan with a condition on temperature. This could help the motor cool down faster when learning mode is activated. We’ll look into that to see if we add this functionality with the next software version !