Slip Ring Current Transfer With Coolant Filtration Against Arcing
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Solution Overview
Problem
Existing devices for transmitting electrical current to a rotor of an electric machine face issues with electrical arcing and creepage currents due to conductive particles and coolant leaks, which compromise safety and efficiency.
Innovation Solution
A device with sliding contacts and a coolant system featuring a separator to remove conductive particles and a filter to prevent arcing and creepage currents, utilizing a filter or sieve as a separator, and a base support for easy assembly and adaptation to different rotor shafts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a coolant system is used to cool sliding contacts, then cooling effectiveness is improved, but electrical conductivity of the coolant increases due to conductive particles, causing arcing and creepage currents
Solution Approach 1:
The device is segmented into functionally independent modules: sliding contacts for current transmission, coolant system for thermal management, and separator for electrical insulation. This segmentation allows each component to optimize its primary function without compromising others - the coolant can be aggressive for cooling while the separator maintains electrical integrity
Solution Approach 2:
A separator (filter or sieve) is introduced as an intermediary component between the sliding contacts and the coolant system. This mediator prevents conductive wear particles from contaminating the coolant, thereby maintaining the coolant's dielectric strength and preventing arcing and creepage currents while allowing cooling functionality to operate effectively
2Reliability
If a separator is added to prevent arcing and creepage currents, then electrical insulation is improved, but device complexity increases
Solution Approach 1:
The separator is designed to perform multiple functions simultaneously: it acts as a mechanical filter to remove particles, an electrical insulator to prevent arcing, and a flow distributor to optimize coolant distribution. This multi-functionality reduces the need for additional separate components, thereby limiting the increase in device complexity
Solution Approach 2:
The separator is designed to be self-cleaning or self-maintaining through the coolant flow itself, which continuously passes through the filter medium. The system utilizes its own operating conditions (coolant circulation) to maintain the separator's functionality without requiring external maintenance mechanisms, thus avoiding additional complexity
3Reliability
If filter surface is increased to improve particle separation, then electrical insulation is improved, but pressure loss increases
Solution Approach 1:
The filter design transitions from a single-plane filtration approach to a three-dimensional filtration structure. The coolant flow is distributed across multiple levels and directions within the separator, effectively increasing the filter surface area without proportionally increasing pressure loss. This dimensional approach allows particles to be captured throughout the volume of the separator rather than just at a single surface
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
Prevents arcing and creepage currents, ensuring safe and efficient operation by maintaining dielectric strength and reducing pressure loss, while being cost-effective and adaptable for various rotor shafts.
Implementation Method 1
at least one separator is provided for separating electrically conductive particles from the coolant of the coolant system
Implementation Method 2
a coolant system for cooling the sliding contacts
Data Source
AI summary
The disclosure relates to a device for transmitting electrical current to a rotor of an electric machine, having a group of sliding contacts each assigned to an electrical pole for transmitting current to a slip ring of the electric machine assigned to each such group. At least one separator is provided for separating electrically conductive particles from the coolant of a coolant system for cooling the sliding contacts.