Rotating electric machine test method, rotating electric machine test device, and rotating electric machine

1. A rotating electric machine test method for testing a rotating electric machine including a rotor and a stator, the rotating electric machine test method comprising:

acquiring test image data by imaging a test target portion which is a part of the rotor by an imager:

generating, as strain change information, change in a strain distribution in the test target portion by digital image correlation based on the acquired test image data; and

determining a time during which operation of the rotating electric machine is able to continue, based on the strain change information.

2. The rotating electric machine test method according to claim 1 , further comprising acquiring initial image data by imaging the test target portion in a first period, wherein

said acquiring the test image data includes acquiring the test image data by imaging the test target portion in a second period after the first period, and

said generating the change in the strain distribution includes generating the strain change information based on the initial image data and the test image data.

3. The rotating electric machine test method according to claim 1 , further comprising determining an appropriate value of a rotation speed of the rotor of the rotating electric machine based on the strain change information.

4. The rotating electric machine test method according to claim 1 , wherein

said acquiring the test image data includes imaging the test target portion by the imager while rotating the rotor.

5. The rotating electric machine test method according to claim 1 , wherein

the rotor includes a rotor core extending in an axial direction and storing a winding, and a retention ring attached to an attachment portion provided at an end in the axial direction of the rotor core, the retention ring retaining the winding, and

the test target portion is provided at the retention ring.

6. The rotating electric machine test method according to claim 5 , wherein the test target portion includes a part of the retention ring that overlaps the attachment portion in a radial direction perpendicular to the axial direction.

7. The rotating electric machine test method according to claim 5 , wherein

the rotor core has a groove-shaped air passage into which gas is introduced, and

the test target portion is provided at a part of the retention ring that overlaps the air passage in a radial direction perpendicular to the axial direction.

8. The rotating electric machine test method according to claim 5 , wherein

the rotor core has a plurality of groove-shaped slots formed with intervals from each other in a circumferential direction about the axial direction, and

the test target portion is provided at a plurality of parts of the retention ring that overlap the plurality of slots in a radial direction perpendicular to the axial direction.

9. The rotating electric machine test method according to claim 1 , wherein

the rotor includes a rotor core extending in an axial direction and storing a winding,

a retention ring attached to an attachment portion provided at an end in the axial direction of the rotor core, the retention ring retaining the winding, and

an end plate attached to the retention ring,

the retention ring has first and second ends, the first end is attached to the attachment portion, and the end plate is attached to the second end, and

the test target portion is provided at the end plate.

10. The rotating electric machine test method according to claim 5 , further comprising estimating a position of crack occurring in the rotor, based on the strain change information and tendency information representing tendency of the strain distribution in the test target portion in a case where crack has occurred in the rotor.

11. The rotating electric machine test method according to claim 10 , wherein

the tendency information includes first distribution information representing the strain distribution in a case where crack has occurred in the retention ring, and second distribution information representing the strain distribution in a case where crack has occurred in the rotor core, and

said estimating the position of crack further includes estimating a position of crack occurring in the retention ring and the rotor core, based on the strain change information and the first and second distribution information.

12. The rotating electric machine test method according to claim 10 , further comprising estimating a dimension of crack occurring at the position estimated in said estimating the position of the crack, based on the strain change information.

13. A rotating electric machine test device for testing a rotating electric machine including a rotor and a stator, the rotating electric machine test device comprising:

an imager to acquire test image data by imaging a test target portion which is a part of the rotor; and

a change information generator to generate strain change information representing change in a strain distribution in the test target portion by digital image correlation based on the test image data acquired by the imager, wherein

the rotor includes a rotor core extending in an axial direction and storing a winding, and a retention ring attached to an attachment portion provided at an end in the axial direction of the rotor core, the retention ring retaining the winding, and

the test target portion is provided at the retention ring.

14. A rotating electric machine comprising a rotor and a stator, wherein

the rotor includes;

a rotor core extending in an axial direction and storing a winding,

a retention ring attached to an attachment portion provided at an end in the axial direction of the rotor core, the retention ring retaining the winding, and

an end plate attached to the retention ring, and

the retention ring or the end plate has a random pattern formed thereon for generating, as strain change information, change in a strain distribution by digital image correlation.

15. The rotating electric machine according to claim 14 , wherein

the retention ring has first and second ends, the first end is attached to the attachment portion, and the end plate is attached to the second end.