Question 307Electricity & Electronics - Assistant Engineer

The correct answer is A) prior to and after conducting the insulation resistance check. Discharging the machine before and after the insulation resistance test is important to remove any accumulated electrostatic or capacitive charge that could skew the test results. Conducting the test with a charged machine could lead to inaccurate readings, as the charge could interfere with the megohmmeter's measurements. Discharging the machine both before and after the test ensures that the readings accurately reflect the insulation resistance of the equipment, without interference from stored electrical charges. The other answer options are incorrect because: B) discharging only after the test does not address the potential impact of the charge on the initial readings, C) discharging only before the test does not address the need to remove any charge that may have built up during the test, and D) discharging during the test would not be practical or recommended, as it could disrupt the measurement process.