Question 528Electricity & Electronics - QMED
70% to passA three-phase electrical system is equipped with ground detecting lamps. If one of the lamps is dark, and remains dark when the test switch is operated, what does this indicate?
Athere is a ground in the line with the dark lamp
Bthere are grounds in two of the three phases
Cthe voltage to the dark lamp is less than that of the system
Dthe dark lamp must be replaced
AI Explanation
The correct answer is D) the dark lamp must be replaced. If one of the ground detecting lamps is dark and remains dark when the test switch is operated, it indicates that the lamp itself is defective and needs to be replaced. The darkness of the lamp does not necessarily indicate a ground in the electrical system. The ground detecting lamps are designed to illuminate when there is no ground fault, so a dark lamp suggests an issue with the lamp itself rather than the electrical system. The other answer choices do not accurately reflect the situation described in the question.
Related Questions
Q383:What is the main purpose of the auxiliary winding on a split-phase, single-phase... Q66:As a DC armature revolves within a stationary magnetic field, the reversals of m... Q324:What is the instrument called a galvanometer used to measure? Q514:By what means is a diesel-driven emergency generator prevented from being parall... Q270:What is the name of the part of the shipboard electrical system used to control ...
Ready to test your knowledge?
Take a Electricity & Electronics - QMED Practice ExamOfficial Resources