Claims
- 1. A method of providing good starting characteristics in a synchronous motor which includes inter-meshed stator poles and a permanent magnet rotor with rotor poles rotating with said inter-meshed stator poles and wherein a field coil which generates flux to cause said rotation of said rotor is disposed adjacent said inter-meshed stator poles in a side-by-side relationship, the method comprising:
- (a) providing shading means for a predetermined number of said stator poles to provide a group of shaded poles and a group of unshaded poles,
- (b) selecting a reference pole from each of said groups,
- (c) determining the flux phase difference between said reference pole and individual poles of a group,
- (d) converting said phase difference to a mechanical angle and locating said individual poles with respect to each other according to said mechanical angle.
- 2. A method according to claim 1 wherein said flux phase difference is determined by comparing difference from a common flux source.
- 3. A method according to claim 2 wherein said common flux source is a core of said field coil.
- 4. A method according to claim 1 wherein said phase difference is converted to said mechanical angle in accordance with the formula:
- E=2.DELTA.n/N,
- wherein
- E=correction from 180.degree. electrical degree location in mechanical degrees
- .DELTA.n=phase difference in electrical degrees (measured)
- N=number of rotor and stator poles combined.
- 5. A method according to claim 1 wherein the unshaded and shaded groups of stator poles are angularly shifted with respect to each other based on an average phase shift produced by said shading means.
- 6. In a self-starting synchronous motor wherein a permanent magnet rotor having rotor poles rotates within an assembly of inter-meshed stator poles in response to flux generated by a field coil that is disposed adjacent to said assembly in a side-by-side relationship an improvement comprising:
- (a) shading means electrically coupled to a predetermined number of stator poles to provide a group of shaded stator poles and a group of unshaded poles, and
- (b) individual poles of each group offset from a reference pole by a mechanical angle determined by a flux phase difference between said reference pole and individual poles of each group.
- 7. In a self-starting synchronous motor according to claim 6 said mechanical angle is determined by the formula:
- E=2.DELTA.n/N;
- wherein
- E=correction from 180 electrical degree location in mechanical degree
- .DELTA.n=phase difference in electrical degrees (measured)
- N=number of rotor and stator poles combined.
Parent Case Info
This application is a continuation of application Ser. No. 965,996, filed Dec. 4, 1978, now abandoned.
US Referenced Citations (6)
Foreign Referenced Citations (1)
Number |
Date |
Country |
1276805 |
Sep 1968 |
DEX |
Continuations (1)
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Number |
Date |
Country |
Parent |
965996 |
Dec 1978 |
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