Stator for Part SetFeatures include: Class H insulation, high fill with heavy gauge wire for maximum efficiency and low-temperature rise. Rotor for Part SetFeatures include: Class H insulation, High current redundant diodes, permanent magnets for self excitation.Options: Lamination stack size can range from 2.5? to 5.0?, shaft lengths, shaft diameters and keyways. Long-life, heavy-duty bearings.