Mabel MacFerran Rockwell

In 1926 MacFerran joined the [[Southern California Edison]] Company Limited as an apprentice testman, becoming the technical assistant to the operating engineer in 1928.<ref name=":2" /> She specialized in studies of high voltage power transmission and system stability. She made one of the earliest applications of the method of [[symmetrical components]] to power systems.<ref name=":5" />

In 1926 MacFerran joined the [[Southern California Edison]] Company Limited as an apprentice testman, becoming the technical assistant to the operating engineer in 1928.<ref name=":2" /> She specialized in studies of high voltage power transmission and system stability. She made one of the earliest applications of the method of [[symmetrical components]] to power systems.<ref name=":5" />

Along with Roy B. Ashbrook, Roy Edwin Quanstrom, and Benjamin F. Dengler, Macferran received US Patent #1,889,086 (filed December 30, 1929, granted November 29, 1932) for a "Protective Gap for Electrical Equipment." This became known as the Serjdetour telephone protector.<ref name=":3">{{Cite journal |last=Hoh |first=Yin Kiong |title=Outstanding women in mechanical engineering |url=http://cristianbeaty.pbworks.com/w/file/fetch/52165005/nyanyanyanyanyanyan.pdf |journal=International Journal of Mechanical Engineering Education |volume=35 |issue=3 |pages=204}}</ref>

Along with Roy B. Ashbrook, Roy Edwin Quanstrom, and Benjamin F. Dengler, Macferran received {{US Patent|1,889,086}} (filed December 30, 1929, granted November 29, 1932) for a "Protective Gap for Electrical Equipment" which became known as the Serjdetour telephone protector.<ref name=":3">{{Cite journal |last=Hoh |first=Yin Kiong |title=Outstanding women in mechanical engineering |url=http://cristianbeaty.pbworks.com/w/file/fetch/52165005/nyanyanyanyanyanyan.pdf |journal=International Journal of Mechanical Engineering Education |volume=35 |issue=3 |pages=204}}</ref>

In 1932 she became an assistant electrical engineer of the [[Metropolitan Water District of Southern California]] at Los Angeles.<ref name=":0" /> She worked on electrical problems with the [[Colorado River Aqueduct]], including economic and engineering studies for the construction power system and the main transmission system.<ref name=":2" /> Macferran was the only woman to work on the design and installation of the electrical systems, specifically the power generating equipment, for Boulder Dam (later renamed [[Hoover Dam]]).<ref name=":1" /> She worked on the economic design of the company's transmission for the dam, which was the basis for her prize-winning paper "Power Limits of 220 Kv Transmission Lines" (co-authored with A. A. Kroneberg).<ref name=":2" /> She also designed the transmission and distribution systems for the [[San Joaquin Valley]] District in California.<ref name=":3" />

In 1932 she became an assistant electrical engineer of the [[Metropolitan Water District of Southern California]] at Los Angeles.<ref name=":0" /> She worked on electrical problems with the [[Colorado River Aqueduct]], including economic and engineering studies for the construction power system and the main transmission system.<ref name=":2" /> Macferran was the only woman to work on the design and installation of the electrical systems, specifically the power generating equipment, for Boulder Dam (later renamed [[Hoover Dam]]).<ref name=":1" /> She worked on the economic design of the company's transmission for the dam, which was the basis for her prize-winning paper "Power Limits of 220 Kv Transmission Lines" (co-authored with A. A. Kroneberg).<ref name=":2" /> She also designed the transmission and distribution systems for the [[San Joaquin Valley]] District in California.<ref name=":3" />