1 Mark the motor shaft casually first, and then turn the motor shaft by hand. Under normal circumstances, the motor shaft will rotate several times with inertia.

2 If the motor shaft does not rotate inertia and gets stuck at a certain point, tap 1 on the opposite side of the stuck position with a small hammer, and tap the front and rear end covers of the motor housing. Don't tap the shaft and turn the motor shaft so many times until you can turn the motor shaft manually, which makes you feel relaxed and have inertia rotation.

These are all based on the sense of touch. Try patiently a few more times.