The M4100 Doble Power Factor Test Set
Testing the effectiveness of electrical insulators can be done using Power factor testing. This test applies to medium and high voltage equipment such as transformers, oil filled capacitors, motors, bushings or any electrical device with an insulator. Doble Engineering is one of the leading manufacturers of Power factor testers. One popular tester is the Doble M4000 M4100 Power Factor Insulation Analyzer.