| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a compressor capable of performing a high-efficiency operation over a wide rotating speed range and also reducing its power consumption viewed for a long period.SOLUTION: A compressor 11 includes a stator 21 provided with a plurality of coils 23U, 23V, and 23W and a rotor 22 having a plurality of poles magnetized. The coils 23U, 23V, and 23W can be switched between a first number N1 of turns and a second number N2 of turns smaller than the first number N1 of turns and also can be brought under field-weakening control at each of the numbers of turns. The second number N2 of turns is so determined that the rotating speed in a rated operation is smaller than a starting rotating speed of the field-weakening control, and the first number N1 of turns is so determined that efficiency is maximum at a rotating speed in an intermediate rotation which is smaller in output than the rated operation. The second number N2 of turns is selected at least for the rated operation and the first number N1 of turns is selected for the intermediate operation.</p> |
