To provide a balance weight easily without requiring any independent unit by setting at least one copper bar of a rotor longer than other copper bars and subjecting the copper bar to aluminum diecasting.
A rotor 1 comprises a rotor core 4 having full-open slots 3 carried on a shaft 2, and secondary conductors formed by inserting a copper bar 5 and a copper bar 6 comprising copper bars 6a, 6b, 6c into full-open slots 3 and coupling the copper pars with an end ring 7 by aluminum diecast. The copper bar 6 (6A, 6B, 6C) is longer than the copper bar 5 in the axial direction. Since a copper bar having a high mass is located at a part of the rotor 1 in the circumferential direction, same effect as providing a balance weight at an end of the rotor 1 is attained. In other words, the work for providing a new balance weight can be eliminated and a balance weight can be provided easily without requiring any independent fixing jig or unit.
OHARAGI HARUO
ARAI KEIJI
MIKAMI HIROYUKI
TAKAHASHI MIYOSHI
SENOO MASAHARU
SATO KAZUO
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