NEMA 11 stepper motor, one phase down
For my dual extruder I use NEMA 11 stepper motors, 0.67 Amp/phase.
These light stepper motors can easy go down when powered with a higher current as specified. Per mistake I fired one up with 1.5 amp and immediately one phase was gone.
When it happens you can conclude this by measuring the resistance from the 2 phases. (see motor spec) Both phases should be close to equal. Mine should be 6 ohm and measured 2.3 and 6 ohm.
Good luck printing
@maoxiankou5 You overloaded the coil with twice it's current limit and are surprised that it failed?
If the stepper current driver is correctly set for the motor there would not be any problem. The standard drivers are only rated for 1A without heatsink and fan so you probably damaged those as well.