Multiple choice: the armature winding of large and medium ac motor is often used for the distribution winding of a double-spaced short distance. A reduces the current harmonics B, reduce the cost C reduces the air gap harmonic magnetic field
A C D short distance can reduce the high frequency harmonic potential, which can also reduce the harmonic current and the magnetic field, because of the double layer, the cost increases
The distribution winding is designed to make the electric potential of the winding into a sine wave; The three phases are distributed evenly in the electric motor, and the third phase alternating current of the output is the same as the uniform three-phase voltage difference of 120 degrees.
Because general winding when using single-layer windings, most (not all) cannot form a short distance, but the whole distance, the motor can effectively weaken the high order harmonic. The double winding will solve both problems.
