When a megohmmeter is being used to test insulation resistance, current leakage along the surface of the insulation is indicated by the megohmmeter's pointer responding in a very unique way. What would be the response of the pointer?
β’ Megohmmeter (megger) behavior when testing insulation resistance β’ Difference between insulation absorption, surface leakage, and a short circuit β’ How the pointer normally behaves when voltage is first applied in a healthy insulation test
β’ Think about what would happen to the reading if current is taking an unstable path along the surface of dirty or moist insulation rather than through the bulk of the insulation. β’ Compare which choices describe a pointer that is settling to a value versus those that show it is unstable or affected only at the instant voltage is applied. β’ Ask yourself: if leakage is irregular and along the surface, would the reading move once and stabilize, or keep showing that irregular behavior while the test voltage is applied?
β’ Identify which choice suggests a continuous, irregular effect rather than a one-time pointer movement at the instant of applying voltage. β’ Eliminate any option where the behavior clearly indicates normal absorption (healthy insulation slowly charging up like a capacitor). β’ Verify which description best matches a pointer affected by changing surface conditions (moisture, dirt paths) during the test rather than a stable internal resistance.
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