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 16-pole magnets; and

the stator comprises 18 coils,

wherein, in response to the rotor being counterrotated by an external force due to a failure in an electric system in the motor apparatus, counter electromotive forces are induced by the coils that have a constant electric phase difference to generate torque in a direction opposite to a direction that the rotor is rotated by the external force to generate a braking force to the motor apparatus, and

wherein the coils that have the constant electric phase difference are electrically connected to form a closed loop such that the counter electromotive forces generate a circulating current in the closed loop to generate the braking force.

2 . The motor apparatus of claim 1 , wherein:

the first groups include a first coil and a tenth coil wound in series, a second coil and an eleventh coil wound in series, and a ninth coil and an eighteenth coil wound in series, such that the first-tenth coil set, the second-eleventh coil set, and the ninth-eighteenth coil set are arranged in parallel;

the second groups include a third coil and a twelfth coil wound in series, a fourth coil and a thirteenth coil wound in series, and a fifth coil and a fourteenth coil wound in series, such that the third-twelfth coil set, the fourth-thirteenth coil set, and the fifth-fourteenth coil set are arranged in parallel; and

the third groups include a sixth coil and a fifteenth coil wound in series, a seventh coil and a sixteenth coil wound in series, and an eighth coil and a seventeenth coil wound in series, such that the sixth-fifteenth coil set, the seventh-sixteenth coil set, and the eighth-seventeenth coil set are arranged in in parallel.

3 . 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 16-pole magnets; and

the stator comprises 18 coils;

the first groups include a first coil and a tenth coil wound in series, a second coil and an eleventh coil wound in series, and a ninth coil and an eighteenth coil wound in series, such that the first-tenth coil set, the second-eleventh coil set, and the ninth-eighteenth coil set are arranged in parallel;

the second groups include a third coil and a twelfth coil wound in series, a fourth coil and a thirteenth coil wound in series, and a fifth coil and a fourteenth coil wound in series, such that the third-twelfth coil set, the fourth-thirteenth coil set, and the fifth-fourteenth coil set are arranged in parallel; and

the third groups include a sixth coil and a fifteenth coil wound in series, a seventh coil and a sixteenth coil wound in series, and an eighth coil and a seventeenth coil wound in series, such that the sixth-fifteenth coil set, the seventh-sixteenth coil set, and the eighth-seventeenth coil set are arranged in in parallel.