Squirrel-cage induction rotating electrical machine, solid rotor, and design method for squirrel-cage induction rotating electrical machine
A squirrel-cage induction rotating electrical machine comprises: a solid rotor, a stator, and bearings. The solid rotor includes a shaft part, a columnar-shaped rotor core part integrally formed with the shaft part and having rotor slots formed therein, and a plurality of conductor bars passing through the respective rotor slots and coupled together at both axial ends outside the rotor core part. The stator includes a cylindrical stator core provided radially outside the rotor core part, and stator windings passing through a plurality of respective stator slots which are formed in the radially inner surface of the stator core. An outer wall and an inner wall of each rotor slot are tilted at a predetermined angle or more with respect to a plane including a rotation axis of the shaft part.
1. A design method for a squirrel-cage induction rotating electrical machine provided with a solid rotor having a shaft part and a rotor core part which are integrally formed and a stator provided radially outside the rotor core part, comprising:
a stator condition setting step of setting dimensions and arrangement pitch of a plurality of stator slots which are formed in a radially inner surface of the stator so as to be disposed with circumferential intervals therebetween and to extend axially;
a rotor condition setting step of setting, after the stator condition setting step, dimensions and arrangement pitch of rotor slots which are formed in a radially outer surface of the rotor core part so as to be disposed with circumferential intervals therebetween and to penetrate axially the rotor core part;
a tilt angle setting step of setting a circumferential tilt angle of the rotor slot after the rotor condition setting step;
a stress calculation step of calculating stress of the rotor core part after the tilt angle setting step;
a temperature calculation step of calculating temperature of the rotor core part after the tilt angle setting step;
an angle range determination step of determining whether processing for examining the circumferential tilt angle of the rotor slot is completed over an entire examination target range of the rotor slot tilt angle and performing the tilt angle setting step and subsequent steps when the determination is negative;
a pitch range determination step of determining whether processing for examining the arrangement pitch of the rotor slots is completed over an entire examination target range of the arrangement pitch of the rotor slots when the determination in the angle range determination step is positive and performing the rotor condition setting step and subsequent steps when the determination in this pitch range determination step is negative; and
a determination step of determining the tilt angle and pitch of the rotor slots based on results of the stress calculation step and temperature calculation step when the determination in the pitch range determination step is positive.