Question 209Electricity & Electronics - Assistant Engineer

The correct answer is D) externally powered resistance temperature detectors. Bearing temperature monitoring systems used for propulsion plant bearings typically employ externally powered resistance temperature detectors (RTDs) rather than thermocouples. RTDs are more accurate and stable than thermocouples, making them the preferred technology for critical temperature monitoring applications like propulsion plant bearings. The other options are incorrect because self-powered thermocouples (A) and self-powered RTDs (B) are less common for this application, and externally powered thermocouples (C) are less accurate and stable than externally powered RTDs (D) for bearing temperature monitoring.