What is trapped field magnet

Currently in the U.S., ferromagnetic materials (permanently magnetized materials) are often costly to obtain because they are supplied from foreign countries.  Center researchers are searching for alternative materials with the potential to produce higher magnetic fields to enable revolutionary motor and generator designs. The science begins with high temperature superconducting (HTS) materials such as yttrium barium copper oxide (YBCO).  HTS implies the material becomes superconductive at the boiling temperature of liquid nitrogen (77 K).  If pucks of these materials are first cryogenically cooled using liquid nitrogen and then exposed to a pulsed magnetic field, a field is trapped on each puck, hence the name Trapped Field Magnet (TFM).

CEM's technical approach:

Working in collaboration with researchers specializing in the creation of YBCO crystalline pucks from University of Houston and nuclear engineers from Texas A&M, CEM’s engineers are trying to incorporate these HTS YBCO pucks into innovative new designs.  Typical applications that attempt to leverage HTS materials, do so using thin wire made from the HTS materials.  This wire is difficult & costly to manufacture and is ultimately quite fragile.  Alternatively, designs that utilize HTS pucks should be less expensive and more robust.  CEM engineers are combining years of expertise in the design of rotating machines and generators to come up with innovative new designs that are smaller, lighter, and more powerful than their predecessors!

There are two primary research challenges being addressed at UT.  The first, is to determine cost effective ways to magnetize the pucks onsite in a large motor generator.  There are obvious manufacturing advantages to site magnetization, but it must be done in a way that is both practical and nearly transparent to the user.  The second, is to achieve adequate thermal insulation on the generator to maintain cryogenic cooling without compromising the electromagnetic performance of the motor or generator.