Manufacturing Methods and Technology for Electromagnetic Components. Volume I. Phase I.
Abstract
Various techniques for the manufacture to low cost, high reliability core type transformers/inductors for missile system applications were investigated and evaluated. A typical missile C core high voltage inductor and toroidal core high voltage transformer were selected as representative test items. Molding technologies ranged from silicone or slush molds for low quantities, individually pressurizable hard models to liquid injection mold (LIM) with transfer presses. Over 40 encapsulation thermo setting compounds for high reliability components were tested and evaluated. Winding techniques included establishing parameters for damage of fine wire windings on square bobbins, and a method of continuously monitoring insulation integrity of magnet wire during winding operations for both toroid, and bobbin/stick winders. Use of spot bonding instead of mylar tape to hold windings in place during the winding operation was developed to eliminate voids caused by the tape during encapsulation/potting. Using a centrifuge for 5 to 10 minutes to remove bubbles from a poured transformer, then curing at room pressure showed promise over the conventional pressure cure at 500 psi for the required cure time and temperature. High voltage gradient estimation and control to achieve corona-free encapsulation was investigated. Various methods of establishing conductive surfaces for faraday shielding of molded bobbins were evaluated. Molds for casting void free bobbins were made. A method of discharge welding of C core bands under tension, without clips, to achieve a low profile, and eliminate solder creepage was demonstrated.
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 01, 1980
- Accession Number
- ADA098167
Entities
People
- Earle R. Bunker
- James R. Arnett
- John L. Williams
Organizations
- Hughes Aircraft Company