Since water is conductive when passing through it, ordinary meggers cannot measure accurately and the measured resistance is very low.
The insulation classification of the double water internally cooled generator is measured
1. The situation measured with a special dual-water megger is: water enters the stator through the coil; the insulation resistance should be greater than 30KΩ; The water-cooled engine should be tested with flowing water. The conductivity should not be higher than: 2.0 × 102 μS/m2 when the water temperature is 20°C. The stator coil is cleaned after the measurement.
If it is a water-cooled generator, a special water agitator should be used when measuring the insulation of the stator, and the water pipe part must be shielded and connected.
1. When measuring insulation, it is not necessary for water to pass through it. When there is noas water, the stator is qualified if measured with a megometer and above 2 M; when the water in the coil is not dried, it is measured with shielded wiring method by megohmmeter. After the water passes, it is measured with water. - Cooled motor insulation tester, and all are qualified above 6M.
2. The water collection ring and the external fixed cold water pipe are isolated by the connection flange.
3. Since the external fixed cold water pipe is grounded, what is protected is: the leakage current generated in the water after the megger is pressurized.