Publications

Abstract not provided.

In the discharge of a capacitor the current was measured with a current viewing transformer (CVT). In addition to measuring the current flowing through the CVT primary, a 51 MHz noise signal was added to the primary current. When the CVT was covered with a gold shield, the noise was eliminated. Analysis of the measured results indicate that the gold layer reflected the electromagnetic that was generated by current flowing in the primary and that the capacitance between the shield and the CVT secondary had no measurable effect on the CVT output.

Sandia National Laboratories has been encapsulating magnetic components for over 40 years. The reliability of magnetic component assemblies that must withstand a variety of environments and then function correctly is dependent on the use of appropriate encapsulating formulations. Specially developed formulations are critical and enable us to provide high reliability magnetic components. This paper will discuss Epoxy, Urethane, and Silicone formulations for several of our magnetic components.

Many Sandia components for military applications are designed for a 20-year life. In order to determine if magnetic components meet that requirement, the parts are subjected to selected destructive tests. This paper reviews the re-design of a power transformer and the tests required to prove-in the re-design. The re-design included replacing the Epon 828/Mica/methylenedianiline (curing agent Z) epoxy encapsulant with a recent Sandia National Laboratory (SNL) developed epoxy encapsulant. The new encapsulant reduces the Environmental Safety and Health (ES and H) hazards. Life testing of this re-designed transformer generated failures; an open secondary winding. An experimental program to determine the cause of the broken wires and an improved design to eliminate the problem was executed. This design weakness was corrected by reverting to the hazardous epoxy system.