Question 84Electricity & Electronics - 1st Asst/Chief

The correct answer is C) to prevent damage to the meter movement from heat generated by the internal shunt. External shunts are used with ammeters to prevent the meter movement from being damaged by the heat generated by the internal shunt. The internal shunt carries the full current being measured, which can generate a significant amount of heat. By using an external shunt, the current is diverted away from the meter movement, protecting it from potential heat-related damage. The other answer choices are incorrect because: A) external shunts are not used to increase meter sensitivity, B) larger resistance shunts can be used internally without an external shunt, and D) external shunts do not directly affect the reactive power factor error.