Current Control Assembly with Centrifugal Contaminant Discharge

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Motor shafts with variable speed drives experience increased susceptibility to induced electrical currents, leading to charge buildup, electrical discharge, and potential damage due to fusion craters and contaminants, which can cause premature failure and operational interference.

Innovation Solution

A current control assembly with a rotor and stator featuring conductive filaments and slots that rotate to discharge contaminants via centrifugal force, preventing entry of contaminants and efficiently transferring current while maintaining a clean environment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the current control assembly operates continuously to manage electrical currents, then electrical discharge damage is prevented, but contaminants accumulate and interfere with operation

Engineering Contradiction:
Improveprevention of electrical discharge damageVSAvoidcontaminant accumulation
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The rotor with discharge openings automatically removes contaminants from the current control assembly during its rotation, enabling the system to self-clean without external intervention. The centrifugal force generated by rotor rotation propels contaminants outward through the discharge openings, maintaining operational reliability without requiring manual cleaning or additional active cleaning mechanisms.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The system actively discards accumulated contaminants through the rotor's discharge openings, preventing their harmful accumulation. By periodically expelling contaminants during rotor rotation, the system maintains a clean operating environment for the conductive filaments and current control components, extending assembly life and preventing performance degradation.

Inventive Principle:
Principle #34Discarding and recovering

2Object-affected harmful factors

If the assembly is removed for periodic cleaning to remove contaminants, then contaminant interference is reduced, but operational time is lost and maintenance becomes impractical for continuous operation

Engineering Contradiction:
Improvecontaminant removalVSAvoiddowntime for cleaning
Core Design Contradiction:
Object-affected harmful factorsVSLoss of time

Solution Approach 1:

The rotor continuously performs the cleaning function during normal operation, eliminating the need for periodic shutdowns and manual cleaning. The self-cleaning mechanism operates automatically as part of the normal rotational cycle, maintaining contaminant-free conditions without sacrificing operational time or requiring maintenance interventions.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The contaminant removal function operates continuously during rotor rotation rather than requiring periodic interruptions. The discharge openings continuously expel contaminants as long as the rotor rotates, ensuring uninterrupted cleaning action that maintains operational efficiency and eliminates downtime associated with manual cleaning cycles.

Inventive Principle:
Principle #20Continuity of useful action

3Speed

If variable speed drives are used to vary motor speed, then motor speed control is improved, but common mode voltage and shaft induced currents increase

Engineering Contradiction:
Improvemotor speed controlVSAvoidshaft induced currents
Core Design Contradiction:
SpeedVSObject-generated harmful factors

Solution Approach 1:

The current control assembly extracts harmful induced currents from the motor shaft by providing a dedicated low-impedance return path through conductive filaments. This separate current control pathway diverts shaft currents away from the bearings, allowing variable speed drives to operate at full capability while the assembly independently manages the harmful electrical effects.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The current control assembly acts as an intermediary between the variable speed drive and the motor bearings. The conductive filaments provide a controlled interface that manages shaft currents, preventing them from causing damage while allowing the variable speed drive to maintain full speed control functionality. The assembly mediates the electrical interaction without interfering with the mechanical speed control function.

Inventive Principle:
Principle #24Intermediary (Mediator)

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

The solution effectively manages electrical currents, prevents contaminant buildup, and extends the life of motor components by reducing physical damage and maintaining operational efficiency.

Implementation Method 1

The plurality of first discharge openings is configured to discharge the contaminant at least partially due to a centrifugal force during rotation of the rotor

Methodology Applied
Scientific EffectCentrifugal force: Centrifugal Force

Implementation Method 2

the plurality of first discharge openings is configured to pressurize an interior of the current control assembly to resist entry of the contaminant during rotation of the rotor

Methodology Applied
Scientific EffectCentrifugal force: Centrifugal Force

Implementation Method 3

A plurality of conductive filaments is coupled to the stator, wherein the plurality of conductive filaments is configured to transfer current between the current control assembly and a shaft

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Data Source

PatentEP2478620B1Current control assembly with drainage and slinger
Publication Date: 2019.11.06 ILLINOIS TOOL WORKS INC
  • EP2478620B1 patent drawingFigure 1
  • EP2478620B1 patent drawingFigure 2
  • EP2478620B1 patent drawingFigure 3

AI summary

The present approaches provide a current control assembly with a rotor and a stator. The stator includes a drain for channeling contaminants away from the assembly and the rotor includes one or more slots that rotate with the rotor for outwardly slinging the contaminants. In one embodiment, a system is provided that includes the current control assembly having a first ring including a first shaft opening and a first discharge opening. The current control assembly also includes a second ring having a second shaft opening and a second discharge opening, wherein the first and second rings rotate relative to one another, and the first and second discharge openings align with one another to discharge a contaminant thereby acting as a slinger. The current control assembly further includes a plurality of conductive filaments configured to transfer current between the current control assembly and a shaft.