Motor apparatus

1. A motor apparatus comprising:

a stator having a plurality of teeth formed in a circumference thereof;

a rotor rotatably installed in the stator, and having a plurality of magnets disposed in a circumference thereof; and

a 3-phase coil part having a plurality of coils wound around the teeth, respectively,

wherein:

the coils having a preset phase difference are arranged in parallel;

the 3-phase coil part comprises a U-phase coil, a V-phase coil, and a W-phase coil;

the U-phase coil includes first groups of the coils having a first phase difference arranged in parallel, each of the first groups including the coils having the same phase difference arranged in series;

the V-phase coil includes second groups of the coils having a second phase difference arranged in parallel, each of the second groups including the coils having the same phase difference arranged in series;

the W-phase coil includes third groups of the coils having a third phase difference arranged in parallel, each of the third groups including the coils having the same phase difference arranged in series;

the first phase difference is 20° to 30°, and the coils in each of the first groups mechanically have an angle difference of 180° therebetween and are electrically in-phase;

the second phase difference is 20° to 30°, and the coils in each of the second groups mechanically have an angle difference of 180° therebetween and are electrically in-phase;

the third phase difference is 20° to 30°, and the coils in each of the third groups mechanically have an angle difference of 180° therebetween and are electrically in-phase;

the rotor comprises 14-pole magnets;

the stator comprises 12 coils;

the first groups include, counting in a counter-clockwise direction on the stator, a first coil and a seventh coil wound in series, and a second coil and an eighth coil wound in series, such that the first-seventh coil set and the second-eighth coil set are arranged in parallel;

the second groups, counting in a counter-clockwise direction on the stator, include a third coil and a ninth coil wound in series, and a fourth coil and a tenth coil wound in series, such that the third-ninth coil set and the fourth-tenth coil set are arranged in parallel; and

the third groups include, counting in a counter-clockwise direction on the stator, a fifth coil and an eleventh coil wound in series, and a sixth coil and a twelfth coil wound in series, such that the fifth-eleventh coil set and the sixth-twelfth coil set are arranged in parallel.