Question 84Electricity/Electronics - 1st Asst/Chief70% to pass
Why are external shunts sometimes used with ammeters?
AI Explanation
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.
Related Questions
#82 How should the shunt used in an ammeter be connected? #83 To properly use a clamp-on type ammeter to check current flow, what must be done FIRST? #85 Which of the listed temperature measuring devices installed on a large turbo-electric alternating current propulsion generator would be the most reliable for monitoring generator temperatures to avoid premature winding insulation failure? #86 An electric propulsion drive system in which the propulsion generator supplies power to both the propulsion motor and ship service loads is referred to as what type of system? #87 Propulsion AC generators creating 4160 VAC use transformers to provide nominally 120 VAC to the automatic voltage regulator. What is the turn’s ratio of this step-down transformer?