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Suzhou Firstall Electrical Machine & Technology Co., Ltd. is a leading Supplier of professional-quality power alternators/generators, Brushless Synchronous AC Alternator , ac generator ,as well as professional service on international trade. FIRSTALL markets its products and service its partner around the world from the office located in Suzhou and Wuxi city Jiangsu province, China.
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Ac generator
Ac generator
An ac generator includes a stator having a stator core with a plurality of slots and a stator winding disposed in the slots and a rotor having trapezoidal claw-shaped pole pieces that alternately extend in opposite directions to interleave each other. In such an ac alternator, each pole piece has a chamfered surface at the tip. The chamfered surface increases a distance from the inside surface of the stator core as the chamfered surface becomes away from the circumferential center of the pole pieces. The chamfered surface has narrower area at the front half in the rotation direction than the rear half.
Background of the ac generator
1. Field of the ac generator
The present invention relates to an ac generator that has a rotor having a plurality of claw-shaped pole pieces and a field coil held inside the pole pieces.
2. Description of the ac generator
It has been found that the magnetic noise of brushless ac generator is caused by the third harmonic wave of magnetic flux that is distorted during operation. In order to reshape the waveform of the magnetic flux into a sine wave, JP-B2-61-11066 proposes an ac generator in which a rotor has scalene trapezoidal claw-shaped pole pieces. That is, the surface of the pole pieces has a trapezoidal shape that is asymmetrical with respect to the center line of the pole piece that is perpendicular to the rotation direction of the rotor.
Summary of the ac generator
Therefore, an object of the invention is to provide a powerful and noiseless ac generators.
An ac generator according to a feature of the invention includes a rotor having trapezoidal claw-shaped pole pieces that alternately extend in opposite directions to interleave each other, in which each of the pole pieces has a chamfered surface at the tip thereof that faces the inside surface of the stator. The chamfered surface has narrower area at the front half of the pole piece in the rotation direction than the rear half. Because such an asymmetrical chamfered surface is formed at limited area after the pole pieces are forged, the pole pieces having accurate size and shape can be provided. When the rotor with such pole pieces and a field coil is rotated in a predetermined direction to brushless alternator, the magnetic flux sharply increases at the front half of the chamfered surfaces of the pole pieces. On the other hand, the magnetic flux gradually decreases at the rear half of the chamfered surfaces. Therefore, a magnetic wave that is similar to the wave provided by the scalene trapezoidal pole pieces of a prior art ac generator is formed.
An ac generator includes a stator having a stator core with a plurality of slots and a stator winding disposed in the slots and a rotor having trapezoidal claw-shaped pole pieces that alternately extend in opposite directions to interleave each other. In such an ac alternator, each pole piece has a chamfered surface at the tip. The chamfered surface increases a distance from the inside surface of the stator core as the chamfered surface becomes away from the circumferential center of the pole pieces. The chamfered surface has narrower area at the front half in the rotation direction than the rear half.
Background of the ac generator
1. Field of the ac generator
The present invention relates to an ac generator that has a rotor having a plurality of claw-shaped pole pieces and a field coil held inside the pole pieces.
2. Description of the ac generator
It has been found that the magnetic noise of brushless ac generator is caused by the third harmonic wave of magnetic flux that is distorted during operation. In order to reshape the waveform of the magnetic flux into a sine wave, JP-B2-61-11066 proposes an ac generator in which a rotor has scalene trapezoidal claw-shaped pole pieces. That is, the surface of the pole pieces has a trapezoidal shape that is asymmetrical with respect to the center line of the pole piece that is perpendicular to the rotation direction of the rotor.
Summary of the ac generator
Therefore, an object of the invention is to provide a powerful and noiseless ac generators.
An ac generator according to a feature of the invention includes a rotor having trapezoidal claw-shaped pole pieces that alternately extend in opposite directions to interleave each other, in which each of the pole pieces has a chamfered surface at the tip thereof that faces the inside surface of the stator. The chamfered surface has narrower area at the front half of the pole piece in the rotation direction than the rear half. Because such an asymmetrical chamfered surface is formed at limited area after the pole pieces are forged, the pole pieces having accurate size and shape can be provided. When the rotor with such pole pieces and a field coil is rotated in a predetermined direction to brushless alternator, the magnetic flux sharply increases at the front half of the chamfered surfaces of the pole pieces. On the other hand, the magnetic flux gradually decreases at the rear half of the chamfered surfaces. Therefore, a magnetic wave that is similar to the wave provided by the scalene trapezoidal pole pieces of a prior art ac generator is formed.