After the positive and negative power supply of the motor is reversed?

When it comes to the positive and negative poles of power supply, it defaults to DC motor. DC motor is divided into permanent magnet DC motor and excitation DC motor. If it is a permanent magnet DC motor, just change the positive and negative poles of the power supply. Except for brushless DC motors, other DC motors will reverse, but for non reversible motors, the spark between brush and commutator will increase and the function of fire suppression system will become weaker The brushless DC motor will burn out after reverse connection For the micro motor with non-polar access, it will not reverse. If it is an excitation DC motor, it has nothing to do with the positive and negative poles of the power supply. It is to take apart the wiring between the excitation winding and the armature winding and exchange them alternately. If you think that single-phase AC motor has positive and negative poles, wrong, AC has no positive and negative poles, and the steering of single-phase AC motor is determined by capacitor phase shift. If it is a three-phase motor, it must be reversed after changing any two phases. If the three-phase motor has frequency conversion control, the commutation does not work, and the steering is determined by the internal control of the frequency converter. As for the basic principles, I learned from middle school: electromagnetic induction effect, left-hand rule, right-hand rule, etc,