first, I apologize for my computer can not enter Chinese.
//hand the 2nd member
but,isn't the voltage of encoder 24v dc??
and for more , check the wires to the conveyor motor
there are two wires to the motor and one of the two have the flag to distinguish.
maybe there is a short circuit in the two wires
one flag is : CE(conveyor encoder wire)
the other is : CM(converyor motor wire)