eddy current brake full report

[seminar class]

PRESENTED BY:
Rodney Kremer
Aaron Noel
Mike Martinez
James Witt

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Eddy Current Brake Mechanism
Introduction
Sponsor
Outline
Background of current Honeywell application
Customer needs
Functional requirements
Constraints and Design effects
Ideal Final Result
Final Design
Analysis
FMEA-Disc Component
Ideality
Bill of Materials
Plans For Next Semester
Background
Honeywell’s current disconnect system
Shear neck
Not effective with variable speeds
Irreversible
Cannot be activated at will
Honeywell’s new disconnect
Needs activation system
Schematic of Shear Neck
Customer Needs
Decelerates ball screw nut to activate disconnect system
Produce required differential torque within given constraints and parameters
Recommended use of eddy current brake system
Mission Statement
Our mission is to develop, design, and test an innovative braking mechanism that will activate a mechanical disconnect system, applicable in a broad range of aerospace generators.
Functional Requirements
Activate Disconnect
Unscrew the ball-screw nut
Be Resettable
Maintenance free
Constraints
Eddy Current Brake
Produce magnetic field
Changing of Magnetic flux induces eddy currents
Eddy Currents produce another magnetic field opposing first
Opposing magnetic fields create force that reduces velocity.
Eddy Current Brake Rationale
Frictionless
Resetable
Light Weight
Few moving parts
Honeywell Recommendation
Components
Electromagnets
Cast Iron Core
Conducting (Copper) Wire
Mounting bolts
Disc
7075 Aluminum
Machined from plates
FMEA - Disc component
Driving Factors for Disc Design
Stress in Disc
Due to Imbalance
Due to Eddy Current Force
Due to Rotating Disc
Temperature of Disc
Electrical Conductivity
Density
Modeling Stress Due to Imbalance
Stress Due to Eddy Current Force
Force on Disc from Eddy currents
Stress Due to Rotating Disc
Heat Transfer (assumptions)
Disc is approximated as flat plate with average velocity, V
Radiation Heat Transfer Rate is Negligible
Disc Rotation Rate 7,200 RPM
Thermo-physical of oil mist can be approximated with that of engine oil
Neglect Heat Transfer out of outer edge of the disc
Neglect Conduction through Disc/shaft mating surface
Eddy Current Force Analysis
Preliminary MATLAB analysis
Faraday Software
Verification
Optimization
Single vs. Paired Electromagnets
Constant vs. Alternating Polarity
Relative Proximity
Coil Shape
Radius
Number of electromagnets/pairs
Visualization
Test Rig
Test Rig Supports
Design Matrix
Ideal Final Result
Predictable and Scalable Torque
No weight
Perfectly balanced
No parts
No frictional contact
Lasts Forever
Takes up no space
Operates at any angular velocity
Needs no power supply
Maintenance Free
Ideality
Bill of Materials
Plans for Next Semester
Continue Remaining Analysis
Build the Test Rig
Build ECBS
Testing and Optimization
Develop Final Product
Faraday’s Law
Equations used with Faraday’s Law:
Lenz’s Law, ,
Induced Current by changing magnetic Flux
Faraday’s Law & Eddy Current Brake Theory
Our understanding of Eddy Current
Relation of Faraday’s Law and Eddy Current brake
Ampere and Faraday’s Equations: &
Design Concepts
A single electro-magnet
Two electro-magnets of opposite Polarity
Two electro-magnets on each side of disc
Rotating arms of electro-magnets
Problem Statement
Activate an existing disconnect system for high-speed Aerospace generator
Non mechanical
Resettable
Activated at will (variable speeds)