Rotor Conductive Coating for Low-Speed Braking Torque
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Solution Overview
Problem
Rotating electric machines have a low braking capacity when the transmission shaft rotates at low speed, which is inadequate for applications requiring significant braking even at low rotational speeds, such as wind turbines.
Innovation Solution
A rotating electric machine design featuring a stator and rotor with electromagnetic conductivity-enhancing coatings, specifically copper, silver, or gold, applied to the rotor faces, increasing braking torque by enhancing electromagnetic interactions, and optionally a protective steel or cast iron coating to maintain efficiency and prevent wear.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If conventional rotor material (steel) is used, then the structure is simple and cost-effective, but the braking torque at low speed is insufficient
Solution Approach 1:
The rotor employs a composite structure consisting of a steel base material with a superficial layer of high electromagnetic conductivity material (copper, silver, or gold). This composite approach combines the structural strength of steel with the superior electromagnetic properties of precious metals, enabling significantly enhanced braking torque at low speeds while maintaining structural integrity and cost-effectiveness through selective material placement only on the braking surface.
Solution Approach 2:
The invention changes the electromagnetic conductivity parameter of the rotor surface by applying a coating layer with significantly higher electromagnetic conductivity than the base steel material. This parameter change in electromagnetic conductivity at the rotor surface directly enhances the electromagnetic interactions with the stator coils, thereby increasing braking torque without fundamentally altering the overall rotor structure.
2Force
If a thick coating layer is applied to increase braking torque, then the electromagnetic conductivity is improved, but the manufacturing complexity and cost increase
Solution Approach 1:
The high electromagnetic conductivity coating is applied locally only on the braking surface of the rotor that directly interacts with the stator coils, rather than coating the entire rotor. This local quality approach concentrates the expensive precious metal material where it is most needed for electromagnetic interaction, reducing overall material cost and simplifying the manufacturing process while maintaining effective braking torque generation.
3Reliability
If no protective coating is applied, then the manufacturing process is simpler, but the rotor is susceptible to friction and wear
Solution Approach 1:
The rotor employs a composite structure consisting of a steel base material with a superficial layer of high electromagnetic conductivity material (copper, silver, or gold). This composite approach combines the structural strength of steel with the superior electromagnetic properties of precious metals, enabling significantly enhanced braking torque at low speeds while maintaining structural integrity and cost-effectiveness through selective material placement only on the braking surface.
Solution Approach 2:
The invention changes the electromagnetic conductivity parameter of the rotor surface by applying a coating layer with significantly higher electromagnetic conductivity than the base steel material. This parameter change in electromagnetic conductivity at the rotor surface directly enhances the electromagnetic interactions with the stator coils, thereby increasing braking torque without fundamentally altering the overall rotor structure.
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
Significantly increases braking torque at low rotational speeds, ensuring effective braking capacity even below 1400 rpm, while maintaining a high level of efficiency and protecting the rotor from friction and wear.
Implementation Method 1
at least a portion of the first face of the rotor arranged opposite the first inductor coils is covered by at least one layer of a first coating, the first coating being made of a material having an electromagnetic conductivity greater than the electromagnetic conductivity of steel
Implementation Method 2
the present invention relates to a rotating electrical machine... characterized in that at least a portion of the first face of the rotor arranged opposite the first inductor coils is covered by at least one layer of a first coating, the first coating being made of a material having an electromagnetic conductivity greater than the electromagnetic conductivity of steel
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
The invention relates to a rotating electrical machine (2) comprising a stator (4) and a rotor (6) capable of pivoting relative to the stator. The stator comprises a first support (8) provided with pole cores (12) and first inductor coils (14) arranged around the pole cores, each pole core (12) having an axis (Y1). The rotor comprises a first face (22) extending perpendicularly to the axes of the pole cores. The first face (22) of the rotor is covered by a layer (26) of a first coating, the first coating being made of a material having an electromagnetic conductivity greater than that of steel.