How is 28 V DC typically used in aircraft like the ERJ-145?

How is 28 V DC typically used in aircraft like the ERJ-145?

• A. To power AC avionics, lighting, sensors, and control systems on the AC side.
• B. To power DC avionics, lighting, sensors, and control systems on the DC side.
• C. To power hydraulic pumps and fuel pumps.
• D. To power standby instruments only.

Answer: (B)

The main idea is that 28 V DC serves as the backbone for powering equipment that operates on direct current. In the ERJ-145, the 28 V DC system feeds the DC side loads: the DC avionics, cockpit and cabin lighting, sensors, and control electronics. These loads are supplied by generators (engine-driven and/or APU), with energy stored in batteries and distributed through DC buses with appropriate protection. When AC power is needed, it comes from the aircraft’s AC system (115 VAC, 400 Hz) or from inverters that convert DC to AC. While there may be electric pumps that run on DC, the standard use of 28 V DC is not limited to pumps; it primarily powers the DC-side avionics, lighting, sensors, and control systems.

The main idea is that 28 V DC serves as the backbone for powering equipment that operates on direct current. In the ERJ-145, the 28 V DC system feeds the DC side loads: the DC avionics, cockpit and cabin lighting, sensors, and control electronics. These loads are supplied by generators (engine-driven and/or APU), with energy stored in batteries and distributed through DC buses with appropriate protection. When AC power is needed, it comes from the aircraft’s AC system (115 VAC, 400 Hz) or from inverters that convert DC to AC. While there may be electric pumps that run on DC, the standard use of 28 V DC is not limited to pumps; it primarily powers the DC-side avionics, lighting, sensors, and control systems.