Screening tests for hermetic magnet wire insulation

Existing tests with modifications in test procedures to reflect the field conditions have been used to determine the effect of refrigerant 22 on wire enamels.With the NEMA apparatus for repeated scrape abrasion, ultimate softening by R22 was found to be the same for AI/PE, PEI and PE/PE and FU regardless of their initial value. The differences between enamels which appear significant after short exposures to R22 became smaller as the exposure time was increased. The scape resistance of Polyimide wire was unaffected by R22.