how can i change motor rotation?
how can i reverse motor rotation....?
That depends on the type of motor. Some are simply NOT reversable.
If you are talking about a motor of the type used in a toy train (DC permanent magnet motor), then swapping the polarity of the voltage to the motor should reverse its rotation.
For three phase a.c. motors, switching any two phases reverses the direction of rotation.
for a three phase motor all you need to do is switch any two phases and your good. For "some" single phase motors you can reverse them, usually you switch two internal wires. There will be a sticker on the outside of the motor somewhere or on the wiring diagram.
For AC/DC brush motors (with series wound stator and armature coils), just reverse the wires to the two brushes. Ditto for shunt wound. For dc motors with permanent magnet stator, reverse the dc polarity, for single-phase ac induction motors (mentioned above) reverse the starting coil connections. For induction motors with repulsion start, use the phase control lever or bolt on the end*. For shaded-pole motors, remove the rotor and turn it end-for-end and re-assemble. For BLDC (brushless dc) motors consult the manufacturer (It probably has a permanent magnet rotor and a Hall-effect sensor).
* see bolt on end for reversing a 1 HP repulsion-start motor at 3:37 minutes into this Youtube video:
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