Newer insulating materials in D.C. motors and generators

Net too long see the range of insulating manuals for d.c. rotating machines was limited to organic fabrics, paper, mica asbestos and a few simple natural resins and compounds. These materials are sound and in many places are still serving then purpose well. In the last decade the number and variety of insulation materials available have increased many fold. The synthetic resins, the fibre glasses, the reconstituted micas, the synthetic fibres and films in their varied forms and characteristics have provided a wealth of new materials and combination of materials which have enabled machine designers to do a better job, providing greater reliability, greater economy, and wider range of application.