07-08-2012, 01:23 PM
Final Design Report Eddy Current Brake System
Final Design Report (1).doc (Size: 1.39 MB / Downloads: 88)
Executive Summary
The Eddy Current Brake Mechanism team has been given the task of designing a braking system that will create a differential torque for the activation of a Honeywell Aerospace Generator Disconnect. This document will state the problem with the current Honeywell disconnect system and how we have taken the voice of the customer into consideration in coming up with a Final Design that will analytically produce the necessary torque for disconnect activation, thereby fulfilling the requirements set by Honeywell Corporation. Upon establishing a Final Design we will explain how the design works and why this particular design is ideal for application for disconnect activation. Our Final Design will comply with all given environmental, functional, and financial constraints and conditions, which will also be clearly defined within this document as well as showing how they were taken into consideration for our design. Seeing as we do not have the capability to transport any testing equipment from Honeywell, the production of a test rig was another task required of us for proof of concept and design. This report will discuss how our design will work within all technical specifications including the test rig’s ability accurately simulating all conditions. We will establish an innovative solution to an existing irreversible, damaging, and costly disconnect system.
Introduction
Document Purpose
The objective of this report is to establish an understanding of requirements set by Honeywell and presenting a conceptual design that fulfills those requirements that will later be put into production and become standard equipment on Honeywell generators. This report will present an Eddy current brake activation system per request of Honeywell. We will present analysis of an Eddy Current Brake System which will lead into why an Eddy Current Brake design is superior to other forms of disconnect activation which we will rule out on various systematic ways.
To give a brief overview, this document will include a problem statement and background as well as all customer needs for Honeywell’s current activation system. Upon establishing the Background and Problem Statement this report will include a brief Conceptual Solution which will adhere to the broad variety of Technical Specifications, also included in this report. The Technical Specifications will present various forms of constraints and information that will be considered and discussed in more detail about their influence in the Design Concept and Structural Analysis portions of this report. The following presents information included within this report:
Background
The disconnect system currently in use by Honeywell for a high speed generator comes in the form of a simple mechanically based part called a shear neck located between the generator and the gear box. For the shear neck to perform its function as a disconnection, the shear neck itself creates an additional constraint. The shear neck is design around a certain angular acceleration/velocity thereby limiting its ability to activate when desired. As a result, the shear neck might not engage at a certain angular acceleration/velocity. Once the shear neck does perform its function properly, and at the required torque, the shear neck must be replaced, hence making this particular disconnect system irreversible. Due to the irreversible nature of the shear neck and lack of function at variable speeds, the shear neck design proves very costly and labor intensive. Elimination of such a mechanically dependant component will prove extremely beneficial to the Honeywell corporation.
Customer Needs
Honeywell is a well respected and innovative company that develops vast amounts of products for both military and commercial applications. The innovative asset is important to the Honeywell Corporation; they must stay one step ahead of their competition at all times. We feel Honeywell has given us the opportunity to become an innovative asset to their company and help in their advancement of aerospace generators. Our contacts, Simon Waddell and Balwinder Birdi, have been extremely helpful in guiding us through the process of developing their new disconnect activation system.
Overview of Eddy Current Generation
Eddy Currents are in induced current that exist in a solid. A changing magnetic flux over an area of the solid will produce an Eddy Current which will create a magnetic field opposing the field producing the Eddy Currents. The opposition of this generated magnetic field is dependant on the changing area. As the area of flux increases the Eddy Current generation is in a “negative” direction. With a decreasing area exposed to the flux the generated Eddy Currents will act in the opposite, “positive”.
Determining Force Produced by Eddy Currents
The analysis for determining the amount of force created by Eddy Currents with a known magnetic field proves extremely tedious. Writing a computer program to calculate the force produced by the eddy currents is not within the scope of this project and would far exceed our timeline. We purchased a software program called Faraday, which will calculate the force generated by the induced eddy current. Nearly all other modes of analysis require the known force created by eddy current generation. To approximate those forces we wrote a basic MATLAB program to simulate the eddy current force generated. The MATLAB program will be discussed in greater detail in the following sections.