scope:

This specification covers the general requirements for devices which convert from a nominal 115/200 Volt, 400 Hertz, 3-phase, alternating current (ac) (see 6.4.1) aircraft electrical system to nominal 28 Volt unregulated direct current (dc) (see 6.4.4) power.

Converters shall be of the following classes, as specified (see 6.2):

Class A: Converters which are self-cooled and conform to the ambient temperature-altitude requirements of MS33543, Curve II, except that no operation shall be required below −55°C. Class B: Converters which are self-cooled and conform to the ambient temperature-altitude requirements of MS33543, Curve I, except that the maximum ambient temperature shall not exceed +85°C and no operation shall be required below −55°C. Class C: Converters which are blast-cooled and conform to the ambient temperature-altitude and inlet airflow requirements specified in the applicable detail specification, and converters which are self-cooled and conform to the temperature-altitude requirements of MS33543, Curve I, except that no operation shall be required below −55°C.

Beneficial comments (recommendations, additions, deletions) and any pertinent data which may be of use in improving this document should be addressed to: Commander, Naval Air Warfare Center Aircraft Division, Electrical Systems Department (SY60), Patuxent River, MD 20670-5304, by using the self-addressed Standardization Document Improvement Proposal (DD Form 1426) appearing at the end of this document or by letter.

intended Use: