What is the voltage of the oil temperature bulb on a turbine engine?

In turbine engines, the oil temperature bulb typically operates at 28 volts DC. This voltage level is common in aircraft systems, particularly those that utilize a 28-volt electrical architecture. The 28V DC is standard for many modern aircraft, providing sufficient power for various sensors and components while ensuring compatibility with the overall electrical system of the aircraft.

The use of 28V DC allows for better efficiency and lower weight due to smaller wire gauges needed for the same power transmission compared to lower voltages, which can lead to heavier wiring systems. Additionally, the use of DC voltage in these components minimizes complications that may arise from AC systems, such as rectification and filtering, making the design simpler and more reliable for crucial sensors like the oil temperature bulb.

Other voltage options presented, such as 12V AC, 24V DC, and 48V AC, do not align with the standard used in turbine engine systems for oil temperature readings.