Magnetics Business & Technology - Summer 2012 - (Page 12)

FEATURE ARTICLE ercivity and permeability are related such that a drop test can offer quick comparisons. One manifestation of this is a drop test using an energized coil in horizontal orientation with a soft iron wire through its center. A sample wire is hung on the horizontal wire. As the energizing voltage is removed, the point at which the sample drops as sensor records the voltage remaining on the coil at the time of drop. To accomplish this an energizing DC voltage is first applied and then added to it is a gradually increasing DC voltage of opposite polarity. The voltage level at drop is a relative indication of the coercivity/remanence of the sample. Another drop test uses energized coils arranged so that the sample falls through the air core coils. Pickup (sense) coils are placed near the top of this stack and at the bottom of this stack to capture time of fall. A simpler version of this is to use permanent magnets placed strategically along the fall path! Surface Resistance Tests Figure 3 shows the wire to be tested is stretched onto a test board so that it is either a single wrap around a polished copper tube or pressed against a polished copper tube. The copper tube has two braided copper strands at each end (single wrap) so that it can be rolled up and down along the test length of the wire (about a meter). One end of the wire is cleaned and attached to an ohmmeter. The other ohmmeter lead is attached to one of the copper braided strands. A measure of tension on the test wire is by a strain gage so that equal levels of tautness can be easily achieved. A turnbuckle connects the strain gage to the frame. Another option for testing surface insula- Figure 3. Surface Insulation Resistance test board tion resistance is to immerse part of the sample in mercury with ohmmeter connected to the mercury and to the sample. A U shaped sample or a sample with the cut end covered with insulating paint or glue can be dipped into the mercury. Other liquids such as water will do if resistivity is controlled. Also metal balls such as bird shot can be used rather than a liquid; particularly if there are small exclusions of surface insulation It is possible that a granular coating might be used rather than a conformal coating in which case liquid testing would be invalid. One More Surface Resistance Test Another test approach is to use a foil such as aluminum foil of a specific width wrapped around the sample in a single turn wrap with the ohmmeter device leads connected to sample and to foil. The foil itself, the width of the foil, the cleanliness of the foil and the tension of the single turn of foil are all variables requiring consistency to attain reliability. This test is attractive because it can accommodate surface insulations conformal or granular. The use of wire in soft magnetics applications brings possibilities of new geometries and design improvements. The use of wire also brings opportunities for new testing standards and protocols that can be less cumbersome than some of the sheet testing. Involved in electronics since the age 14, Harrie Buswell of Buswell Energy LLC, has also studied, researched, practiced and taught creativity thinking with a Ph.D. from the University of Georgia. During 10 years at Berea College in Kentucky he repeatedly taught a class he developed entitled "Thinking with Computers". At Georgia Tech for 15 years he operated and managed a successful NSF sponsored instrumentation outreach program. Although seven years at Engineering Extension Service at Iowa State University, Buswell alternated industry and academics across his career. Currently working on three patent applications he holds 11 issued United States Patents and several foreign patents. INNOVATION IS OUR MAIN ATTRACTION World leader in design and production of permanent magnets systems. We are a vertically integrated rare earth magnet producer, creating precise magnetic fields for critical aerospace and high performance applications. • In-house 2D and 3D Finite Element Analysis. • SmCo UHT™ magnets operating continuously up to 550° C. • Specialty grades materials with low change in magnetic flux with temperature. • Fabrication of complex magnet assemblies to demanding specifications. Call us for a free technical consultation 924 Links Avenue, Landisville, PA 17538 800.824.2735 • 717.898.2294 • Fax: 717.898.0660 www.electronenergy.com 12 Magnetics Business & Technology • Summer 2012 www.MagneticsMagazine.com http://www.electronenergy.com http://www.MagneticsMagazine.com

Table of Contents for the Digital Edition of Magnetics Business & Technology - Summer 2012

Magnetics Business & Technology - Summer 2012
Editor's Choice
Injection Molded Magnets for Electrical Machines
The Process of Developing and Testing a New Transformer
Rare Earths & Corporate Social Responsibility
Research & Development
RE-use, RE-duce, RE-cycle, RE-place
Magnets • Materials • Measurement
Application • Component Developments
Industry News
Rare Earth Crisis Dissected: Securing the Future
Marketplace
Advertising Index
Spontaneous Thoughts: The End of Axial Pressing?

Magnetics Business & Technology - Summer 2012

Magnetics Business & Technology - Summer 2012 - (Page Intro)
Magnetics Business & Technology - Summer 2012 - Magnetics Business & Technology - Summer 2012 (Page Cover1)
Magnetics Business & Technology - Summer 2012 - Magnetics Business & Technology - Summer 2012 (Page Cover2)
Magnetics Business & Technology - Summer 2012 - Magnetics Business & Technology - Summer 2012 (Page 3)
Magnetics Business & Technology - Summer 2012 - Editor's Choice (Page 4)
Magnetics Business & Technology - Summer 2012 - Editor's Choice (Page 5)
Magnetics Business & Technology - Summer 2012 - Injection Molded Magnets for Electrical Machines (Page 6)
Magnetics Business & Technology - Summer 2012 - Injection Molded Magnets for Electrical Machines (Page 7)
Magnetics Business & Technology - Summer 2012 - Injection Molded Magnets for Electrical Machines (Page 8)
Magnetics Business & Technology - Summer 2012 - Injection Molded Magnets for Electrical Machines (Page 9)
Magnetics Business & Technology - Summer 2012 - The Process of Developing and Testing a New Transformer (Page 10)
Magnetics Business & Technology - Summer 2012 - The Process of Developing and Testing a New Transformer (Page 11)
Magnetics Business & Technology - Summer 2012 - The Process of Developing and Testing a New Transformer (Page 12)
Magnetics Business & Technology - Summer 2012 - Rare Earths & Corporate Social Responsibility (Page 13)
Magnetics Business & Technology - Summer 2012 - Rare Earths & Corporate Social Responsibility (Page 14)
Magnetics Business & Technology - Summer 2012 - Rare Earths & Corporate Social Responsibility (Page 15)
Magnetics Business & Technology - Summer 2012 - Research & Development (Page 16)
Magnetics Business & Technology - Summer 2012 - RE-use, RE-duce, RE-cycle, RE-place (Page 17)
Magnetics Business & Technology - Summer 2012 - RE-use, RE-duce, RE-cycle, RE-place (Page 18)
Magnetics Business & Technology - Summer 2012 - RE-use, RE-duce, RE-cycle, RE-place (Page 19)
Magnetics Business & Technology - Summer 2012 - RE-use, RE-duce, RE-cycle, RE-place (Page 20)
Magnetics Business & Technology - Summer 2012 - Magnets • Materials • Measurement (Page 21)
Magnetics Business & Technology - Summer 2012 - Application • Component Developments (Page 22)
Magnetics Business & Technology - Summer 2012 - Application • Component Developments (Page 23)
Magnetics Business & Technology - Summer 2012 - Industry News (Page 24)
Magnetics Business & Technology - Summer 2012 - Rare Earth Crisis Dissected: Securing the Future (Page 25)
Magnetics Business & Technology - Summer 2012 - Rare Earth Crisis Dissected: Securing the Future (Page 26)
Magnetics Business & Technology - Summer 2012 - Rare Earth Crisis Dissected: Securing the Future (Page 27)
Magnetics Business & Technology - Summer 2012 - Rare Earth Crisis Dissected: Securing the Future (Page 28)
Magnetics Business & Technology - Summer 2012 - Advertising Index (Page 29)
Magnetics Business & Technology - Summer 2012 - Spontaneous Thoughts: The End of Axial Pressing? (Page 30)
Magnetics Business & Technology - Summer 2012 - Spontaneous Thoughts: The End of Axial Pressing? (Page Cover3)
Magnetics Business & Technology - Summer 2012 - Spontaneous Thoughts: The End of Axial Pressing? (Page Cover4)
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