Question 500Electricity & Electronics - QMED
70% to passA thermal-magnetic circuit breaker for a 300 kW alternator is rated at 500 amperes at full continuous load. Which of the following conditions will trip the breaker?
ASustained current draw of 450 amperes for 2 hours.
BSustained current draw of 500 amperes for 10 minutes.
CMomentary current draw of 1000 amperes for 3 seconds.
DInstantaneous current draw of 5,000 amperes.
AI Explanation
The correct answer is D) Instantaneous current draw of 5,000 amperes. The thermal-magnetic circuit breaker is designed to trip when the current draw exceeds the rated capacity, which in this case is 500 amperes. An instantaneous current draw of 5,000 amperes would greatly exceed the breaker's rating, causing it to trip immediately to protect the alternator from damage. The other options, while potentially problematic, would not necessarily trip the breaker immediately, as they do not exceed the 500-ampere rating by a large enough margin.
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