GE - Rockford produces custom-designed environmental air temperature controllers for the aerospace industry. These environmental controllers are one element of the environmental control system which typically consists of temperature sensor(s), temperature selector(s) and electrically actuated butterfly valves. GE environmental temperature controllers contain bi-directional solid- state electronic control and operate from input power of 115 VAC, 400 Hz single-phase power or 28 VDC. Nominal output voltage of the AC controllers is 115 VAC, 400 Hz whereas output power of the 28 VDC controllers is typically 2.0 amps at 28 VDC.