A GPU start is recommended at ambient temperature below approximately minus 15 degrees C with a DC voltage minimum of how many volts?

A GPU start is recommended at ambient temperature below approximately minus 15 degrees C with a DC voltage minimum of how many volts?

• A. 24V
• B. 26V
• C. 28V
• D. 30V

Answer: (C)

Cold temperatures raise the difficulty of starting by increasing resistance and reducing available current, so the GPU must deliver a solid, stable 28V to the starter circuit under load. Aircraft DC systems are designed around a 28V bus, and at ambient temperatures below roughly minus 15 degrees C, using a DC voltage minimum of 28V ensures the starter and associated circuits receive enough voltage to spin up the engine reliably. voltages like 24V or 26V would be too low to guarantee starting under these cold conditions, while 30V can exceed what the system is designed to tolerate. So, the reliable minimum for a cold-start scenario is 28V.

Cold temperatures raise the difficulty of starting by increasing resistance and reducing available current, so the GPU must deliver a solid, stable 28V to the starter circuit under load. Aircraft DC systems are designed around a 28V bus, and at ambient temperatures below roughly minus 15 degrees C, using a DC voltage minimum of 28V ensures the starter and associated circuits receive enough voltage to spin up the engine reliably. voltages like 24V or 26V would be too low to guarantee starting under these cold conditions, while 30V can exceed what the system is designed to tolerate. So, the reliable minimum for a cold-start scenario is 28V.