Slip Ring Module Electrostatic Dissipation via Molded Conductor
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Solution Overview
Problem
Existing slip ring assemblies in electric machines experience electrostatic voltage buildup during rotor rotation, leading to potential damage or destruction of electronic components due to uncontrolled discharges, especially with new drive materials like multi-V belts, and previous solutions compromise the reliability of the excitation coil's functioning.
Innovation Solution
Incorporating an additional molded conductor with specific conductivity levels and materials, such as a polymer composite, to form a direct electrical connection from the connecting conductor to the slip ring assembly, allowing for high-voltage testing and electrostatic discharge dissipation without causing short circuits, and using an injection molding or spraying process for precise and reliable manufacturing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a conductive coating is applied to the holder to dissipate electrostatic voltage, then electrostatic discharge is prevented, but the excitation coil can no longer be reliably tested for short circuits
Solution Approach 1:
The holder is segmented into two distinct functional zones: an insulating region for structural support and coil testing, and a conductive region for electrostatic voltage dissipation. This segmentation allows each zone to perform its specific function without interfering with the other, resolving the contradiction between preventing electrostatic discharge and maintaining testing capability.
Solution Approach 2:
Different electrical properties are applied to different regions of the holder. The region requiring electrostatic dissipation is made conductive, while the region requiring testing capability remains insulating. This local differentiation of material properties allows simultaneous achievement of both functions in different locations of the same component.
2Reliability
If an additional molded conductor is added to enable high-voltage testing and electrostatic dissipation, then testing capability and electrostatic protection are improved, but the device complexity increases
Solution Approach 1:
The molded conductor integrates multiple functions into a single component: it provides a test lead for high-voltage testing, serves as an electrostatic discharge path, and structurally connects the excitation coil to the holder. By merging these functions into one integrated component rather than adding separate elements, the increase in complexity is minimized while achieving the desired reliability improvements.
Solution Approach 2:
The molded conductor is designed as a multi-functional element that simultaneously enables high-voltage testing, provides electrostatic dissipation, and maintains electrical connection. This universal component performs multiple critical functions that would otherwise require separate elements, thereby limiting the increase in device complexity.
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
Enables reliable and precise high-voltage testing of the excitation coil, prevents damage from electrostatic discharges, and ensures reliable electrostatic dissipation without affecting the excitation current, thereby improving the reliability and reproducibility of the slip ring assembly's performance.
Implementation Method 1
high electrostatic voltages build up, which discharge suddenly when an undefined limit is exceeded
Implementation Method 2
the electrostatic voltage is dissipated from the electromagnetic iron part via the negative slip ring to the electrical ground of the electric machine
Implementation Method 3
using an injection molding or spraying process for precise and reliable manufacturing
Implementation Method 4
If the additional molded conductor is embodied by molding on the at least one first connecting conductor, the spraying on of this additional molded conductor also permits the creation of an exact precise additional molded conductor
Data Source
AI summary
A slip ring module (76) for a rotor (40) of an electrical machine (10), in particular, an alternator is disclosed, comprising at least one first slip ring (79) with at least one first connecting conductor (103) held in sections of an insulation material (101) for the slip ring module (76), in electrically conducting connection with at least one first slip ring (79) and with an end (115) of the connection conductor (103), facing away from the first slip ring (79), provided for connection to an excitation coil (61). The invention is characterised in that the slip ring module (76) has a further formed conductor (139) forming a direct electrical connection from the first connection conductor (103) to a surface (142) of the slip ring module (76). An electric machine is also provided, in particular, an alternator for motor vehicles, comprising a rotor (40), supporting an excitation coil (61), said slip ring module (76) providing the power supply to the excitation coil (61). Furthermore, a method for production of a slip ring module (76) for an electric machine, in particular, an alternator, is disclosed, wherein, in one step, at least one connector conductor (103) is bonded to an electrically insulating holder (100), in particular, by means of a injection moulding process and, in another step, the connection conductor is directly connected to an electrically conductible conductor (139) made from a composite material, the composite material comprising electrically conducting and electrically non-conducting regions.