Manufacturing Methods and Technology for Electromagnetic Components. Volume 2. Phase 2
Abstract
Various techniques for the manufacture of 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 (100's/month), individually pressurizable hard molds (1000's/month), to liquid injection mold (LIM) with transfer presses (10,000/month). Over 40 encapsulation thermo setting compounds for high reliability components were tested and evaluated. Two compounds were selected, one optimum for low stress applications, the other for high voltage, corona free applications. Cure times are main limitation of production rates, pointing up a need for faster cure time materials of at least an order of magnitude. 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.
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 01, 1980
- Accession Number
- ADA098168
Entities
People
- Earle R. Bunker
- James R. Arnett
- John L. Williams
- King H. Li
Organizations
- Hughes Aircraft Company