Generator Field Coils Using Flat Wire Turns
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Solution Overview
Problem
Existing generators with rounded or circular wire windings face challenges in achieving large pole arc sizes and efficient magnetic flux communication while managing mechanical stress, leading to limitations in power density and waveform quality.
Innovation Solution
The use of flat wire turns stacked radially and obliquely to form field coils with bowed end turn portions, which tightly abut rotor teeth, allowing for larger pole arcs and reduced flux density, thereby improving mechanical stress and power density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If rounded or circular wire windings are used in the rotor, then the generator structure is simpler to manufacture, but the pole arc size is limited and flux density becomes excessive
Solution Approach 1:
The patent changes the geometric parameter of the wire from circular cross-section to flat rectangular cross-section. This parameter change allows the winding to conform better to the rotor tooth geometry, enabling larger pole arc sizes while distributing the magnetic flux more evenly, thereby reducing peak tooth stress.
Solution Approach 2:
The invention introduces a new dimensional aspect by using flat wire with rectangular cross-section instead of circular wire. This additional dimensional freedom allows the winding to wrap more effectively around the rotor tooth, increasing the pole arc coverage area without proportionally increasing the mechanical stress on the tooth.
2Power
If rounded or circular wire windings are used, then manufacturing is easier, but power density is limited
Solution Approach 1:
By changing the wire cross-sectional shape from circular to flat rectangular, the patent optimizes the space utilization within the rotor winding. The flat wire configuration allows for more efficient packing and better magnetic coupling, thereby increasing the power density of the generator.
3Quantity of substance
If larger pole arcs are achieved with circular wire, then more magnetic flux can be communicated, but mechanical stress on rotor teeth increases
Solution Approach 1:
The patent uses flat wire geometry to achieve better distribution of magnetic flux across larger pole arcs. The rectangular cross-section allows the winding to maintain better contact and more uniform flux distribution, increasing the quantity of magnetic flux communicated while reducing peak mechanical stress on the rotor teeth.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Generators with flat wire windings can operate with lower tooth stress and higher power density, enhancing electrical efficiency and waveform quality compared to those using circular wire windings.
Implementation Method 1
As the rotor rotates relative to the stator the magnetic elements communicate magnetic flux to the stator. The magnetic flux in turn induces an electric current in the stator winding
Implementation Method 2
an electric excitation current is applied to the windings to generate and/or tune the magnetic flux communicated by the rotor
Data Source
Figure 1
Figure 2
Figure 3~5
AI summary
A generator includes a stator with a stator winding (106), a rotor core (110) with a rotor tooth (122) supported for rotation relative to the stator about a rotation axis, and a field winding (112). The field winding includes a field coil (140) that is seated on the rotor tooth. The field coil includes two or more flat wire turns (154) stacked with one another and formed such edges of the field coil tightly engage circumferential faces of the tooth. Electrical systems and methods of making generators are also described.