Question 474Motor Plants - Assistant Engineer

The correct answer is A) Not more than 30 seconds. Electric starter motors on diesel engines are designed for very brief, intermittent use to start the engine. Continuous operation beyond 30 seconds can cause the starter motor to overheat and potentially become damaged. This is due to the high electrical current draw of the starter motor, which generates substantial heat that cannot be dissipated effectively during prolonged use. The other answer choices are incorrect because they allow for longer continuous operation, which exceeds the design limitations of the starter motor and would likely lead to overheating and potential damage.