A megger is being used to test the...

Question 1 / 270705eccefa4bacbc34ba4d4840a

Question 1 of 270705eccefa4bacbc34ba4d4840a

A megger is being used to test the insulation of an AC generator. What will be the measured resistance value of a dry, clean winding?

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Question 1 of 27070

A megger is being used to test the insulation of an AC generator. What will be the measured resistance value of a dry, clean winding?

🔍 Key Concepts

• Insulation resistance testing using a megger (megohmmeter) • How dry, clean insulation behaves over several minutes under a steady DC test voltage • Effect of dielectric absorption and temperature on measured resistance

💭 Think About

• Think about what happens to a good, dry, clean winding when a constant DC high voltage is applied: does its resistance trend up, down, or stay flat over a few minutes? • How does the insulation’s dielectric absorption affect the reading over time—does it cause a gradual increase, a gradual decrease, or an initial fluctuation then leveling? • Would a rising winding temperature during the test usually make insulation resistance go up or down?

✅ Before You Answer

• Identify which choice best matches the typical time behavior of a healthy insulation resistance test curve (IR vs. time). • Eliminate any options that contradict the known effect that higher temperature generally lowers insulation resistance. • Focus on which description matches a good, dry, uncontaminated winding, not one that is wet, dirty, or deteriorated.

Question 1 of 27070

A megger is being used to test the insulation of an AC generator. What will be the measured resistance value of a dry, clean winding?

continue to rise as test potential is maintained, becoming fairly steady as the dielectric-absorption effect of insulation stabilizes

remain constant as the temperature of the windings increases

continue to drop as test potential is maintained, becoming fairly steady after 5-7 minutes

stabilize after approximately 2-4 minutes of fluctuation

Question 1 / 270705eccefa4bacbc34ba4d4840a

Question 1 of 270705eccefa4bacbc34ba4d4840a

A megger is being used to test the insulation of an AC generator. What will be the measured resistance value of a dry, clean winding?

Back

Question 1 of 27070

A megger is being used to test the insulation of an AC generator. What will be the measured resistance value of a dry, clean winding?