Starship Asterisk*

Hello everyone,
I have a planetary gear stepper motor.
If I try to turn the shaft manually at the output of the planetary gear, I can't do it.
But if I separate the gear from the stepper motor, I can turn the shaft very easily.

So does the stepper motor have some kind of brake built in? How does it work and can it be removed?

Yes, the behavior you're describing is likely due to a feature called "holding torque" in the stepper motor. Stepper motors can hold their position when they are not actively powered, thanks to the residual magnetic attraction between the rotor (the part that turns) and the stator (the stationary part).