Induction motor

(54) INDUCTION MOTOR

(75) Inventors: Kosei Nakamura, Susono; Michi Masuya; Hi sushi Maeda, both of Oshino-mura; Shinpei Uemura,

Minamitsuru-gun, all of (JP)

(73) Assignee: Fanuc LTD, Yamanashi (JP)

( * ) Notice: Subject to any disclaimer, the term of this patent is extended or adjusted under 35 U.S.C. 154(b) by 0 days.

(21) Appl. No.: 09/254,006

(22) PCT Filed: Jun. 30, 1998

(86) PCT No.: PCT/JP98/02934 § 371 Date: Mar. 1, 1999

§ 102(e) Date: Mar. 1, 1999

(87) PCT Pub. No.: WO99/00890 PCT Pub. Date: Jan. 7, 1999

(30) Foreign Application Priority Data Jun. 30, 1997 (JP) 9-187241

(51) Int. C I. H02K 17 12

(52) U.S. C I 310/166

(58) Field of Search 310/166, 179,

310/180, 184, 188, 189, 198, 200, 159;

363/104

(56) References Cited

U.S. PATENT DOCUMENTS

An induction motor capable of obtaining a high power characteristic in a wide range without producing induced voltage. Awinding for each phase is composed of a plurality of winding components having the same number of turns. When high torque is needed with low speed rotation, a Y-connection in which winding components for each phase are connected in series is formed as shown in FIG. 2a. For medium low speed rotation, a A-connection in which winding components for each phase are connected in series is formed as shown in FIG. 2b. For medium high speed rotation, a Y-connection in which winding components for each phase are connected in parallel is formed as shown in FIG. 2c. For high speed rotation, a a-connection in which winding components for each phase are connected in parallel is formed as shown in FIG. 2d. Using the entire winding for each phase, the number of turns is decreased stage by stage to switch from low speed rotation to high speed rotation. Since there is no unused part of windings, there is no problem of induced voltage. A fall in power at the time of switching the winding formation can be restrained, so that a high power characteristic can be obtained in a wide range.

1 Claim, 9 Drawing Sheets