What type of electrical test is performed to check the insulation resistance of motor coils?

The correct choice is the Insulation Resistance Test, which is specifically designed to measure the resistance of electrical insulation. This test is crucial for assessing the integrity and effectiveness of insulation materials used in motor coils. It helps identify any deterioration or breakdown in the insulation that could lead to electrical faults, thus ensuring safe operation and preventing equipment damage.

During the Insulation Resistance Test, a high voltage is applied to the insulation while measuring the resulting leakage current. A high insulation resistance value indicates that the insulation is intact and functioning properly, while a low value suggests that there may be an issue that needs to be addressed.

Other tests, such as Voltage Tests, evaluate the operational voltage in a circuit but do not focus on the insulation quality. Continuity Tests check if there is a complete electrical path but do not measure insulation effectiveness. Leakage Tests often refer to measuring current that leaks through an insulation barrier, but they do not specifically characterize the insulation resistance. Thus, the Insulation Resistance Test remains the most appropriate choice for assessing the insulation in motor coils.