Electrical generator or motor structure – Dynamoelectric – Rotary
Reexamination Certificate
1998-11-23
2001-04-03
Nguyen, Ngoc-Tran (Department: 2834)
Electrical generator or motor structure
Dynamoelectric
Rotary
C310S091000
Reexamination Certificate
active
06211596
ABSTRACT:
BACKGROUND OF THE INVENTION
Claw-pole machines are synchronous machines in which only one magnet-wheel coil is required for electrically supplying all of the exciter poles with the magnetic excitation required for the magnet-gap field. These machines are especially well-suited for higher pole-pair numbers p, because the salient-pole embodiment that is otherwise necessary provides too little space for the salient-pole coils.
Claw-pole synchronous machines are tried-and-true machines for generating currents in the area of low power. The single excitation pole
1
generates a magnetic field in the axial direction
2
that is partitioned onto the claw poles at the circumference of the rotor and, because of the alternatingly-meshing claw poles in the magnet gap, appears as a magnetic field having an alternating polarity (FIG.
1
).
It is known from the European patent publication EP 0394528B1 to provide tangentially-acting permanent magnets to prevent magnetic scattering between the claw-pole fingers and the poles of the claw-pole toothed wheel; in a corresponding design, these permanent magnets support the magnet-gap field of the exciter coils. When the electrical excitation is shut off, the permanent-magnet field magnetically short-circuits over the claw-pole toothed wheel, the claw-pole-finger systems and the exciter yoke, that is, despite the excitation by the permanent magnets, the total magnet-gap field is completely settable.
At higher powers, the claw-pole embodiment is problematic, however, because the magnetically axially-acting exciter coil must encompass the entire exciter useful flux and the scatter flux of all p rotor poles of a claw side. Consequently, the cylindrical exciter yoke, which passes axially through the exciter coil, must have a minimum diameter, as stipulated by the reasonable magnetic saturation, that severely narrows the radial space for the exciter coil unless the embodiment is limited to axially-short stators. A consequence of this is high pole numbers, which, at a given rpm, drive the remagnetization frequency up. This causes greater losses, particularly in the iron parts.
SUMMARY OF THE INVENTION
It is the object of the invention to reduce these losses without worsening the mechanical stability of the pole arrangement.
This object is accomplished by a claw-pole machine having a stator, a rotor, and an exciter coil, that is wound on a solid core in the rotor, with the solid core extending in the radial direction into two claw magnet wheels that end in a plurality of claw-pole fingers, having a plurality of solid, radially-outward-oriented parts, which alternate axially, starting from two sides, where in a pluraity of U-shaped metal sheets are attached to the solid radially-outward-oriented parts of the claw-pole fingers, with the sheets being layered one on top of the other in the axial direction to prevent eddy currents. Additional features of the invention are described in the dependent claims.
REFERENCES:
patent: 3571637 (1971-03-01), Henningry et al.
patent: 4316111 (1982-02-01), Merki et al.
patent: 4780637 (1988-10-01), Wolcott
patent: 5130595 (1992-07-01), Arora
patent: 5536987 (1996-07-01), Hayashi et al.
patent: 5651384 (1997-07-01), Rudrich
patent: 5814907 (1998-09-01), Bandera
patent: 195 02 148 A1 (1995-01-01), None
patent: 195 02 184 A1 (1995-01-01), None
patent: 0 394 528 B1 (1989-04-01), None
patent: 0 723 330 A2 (1995-10-01), None
Daimler-Benz Aktiengesellschaft
Kinberg Robert
Nguyen Ngoc-Tran
Nguyen Tran N
Venable
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