William Morris Mordey

William Morris Mordey (28 March 1856 – 1 July 1938) was a British electrical engineer. He was the chief electrician of the Brush Electrical Engineering Company, a consulting engineer in the partnership Mordey and Dawbarn, and the president of the Institution of Electrical Engineers from 1908 to 1909.^[1] He is known for the invention of the Mordey alternator and the discovery of the "Mordey Effect".^[1] Mordey also had coined the term "V curve".^[2]

Mordey was born on 28 March 1856 at Donnywell in County Durham.^[1] He was the second son of John Goodchild Mordey and the grandson of Dr. William Mordey, who had served multiple terms as the mayor of Sunderland.^[1]

At the age of fourteen, Mordey entered the postal telegraph service. He was employed briefly in London before being transferred to Bradford.^[1] During this time, he devoted his leisure hours to the study of physics as it related to telegraphy. Despite having no formal education, he successfully conducted classes in telegraphy, magnetism, and electricity for the Science and Art Department and the City and Guilds of London Institute.^[1] In 1881, he sat for the examination with his own class and obtained the second prize and medal of the City and Guilds Institute in the advanced stage of the subject.^[1]

At the end of 1881, Mordey left the telegraph service to join the Anglo-American Brush Electric Light Corporation (later the Brush Electrical Engineering Company), where he became the company's chief electrician.^[1] He remained with the firm until 1897, devoting his work to the design of alternating current (AC) and direct current (DC) dynamos, motors, and transformers.^[1]

Mordey constructed a special armature type for DC dynamos and an original AC alternator early in his career. The "Mordey Victoria" alternators played a significant role in the generation of single-phase current and the transition from gas lighting to electric lighting.^[1] These alternators, often paired with Raworth engines, were installed at the Bankside Power Station of the City of London Electric Lighting Company and other electric power plants in Britain and abroad.^[1]

The Mordey alternator differed significantly from other machines of the period. The magnet wheel, which contained a single coil, was designed so that the poles gripped around the thin disc-shaped armature winding in such a way that all poles on one side had the same polarity.^[3] While this design eventually lost its significance for standard power generation, its principles were later applied to high-frequency current generators used in wireless telegraphy.^[3]

After leaving Brush, Mordey established himself as a consulting engineer in London. By 1898 he was operating from 82 Victoria Street.^[1] He became a partner in the firm Mordey and Dawbarn.

Throughout his career, he contributed to the understanding of electromagnetic induction, magnetic field laws, and eddy currents through various investigations and publications.^[3] He served as president of the Institution of Electrical Engineers from 1908 to 1909.^[1]

Mordey filed at least 38 British patents, many of which were also filed internationally.^[1] Notable patents and collaborations included:

• c. 1889: A new electric generator.^[1]
• 1897: Methods for removing electrical charges from paper during manufacture (with Henry John Rogers).^[1]
• 1898: Improvements in AC arc lamps (with Henry Bevis).^[1]
• 1900–1902: Electricity meters, including the Mordey-Fricker meter (with Guy Carey Fricker), which was demonstrated at the Royal Society.^[1]
• 1901: Step-by-step telegraphic apparatus (with Walter Samuel Steljes).^[1]
• 1902: AC traction systems (with Arnold Greaves Hansard).^[1]
• 1912: Coverings for steam boilers (with Alphons Custodis Chimney Construction Co).^[1]

Mordey effect is a phenomenon observed in armatures of electric machines: at full loads the magnetic hysteresis decreases. The effect was expressed by S. P. Thompson as follows: "When an armature core is rotated in a strong magnetic field, the magnetization of the iron is being continually carried through a cycle, but in a manner quite different from that in which it is carried when the magnetizing force is periodically reversed, as in the core of a transformer. Mordey has found the losses by hysteresis to be somewhat smaller in the former case than in the latter."^[4]

Mordey died in Warlingham, Surrey, on 1 July 1938 at the age of 82.^[5][1]

• M.I.E.E. (1906). "The Electric Transmission of Power". English Mechanics and the World of Science. 83. E. J. Kibblewhite: 590–592. Retrieved 2024-12-03.
• This article incorporates text from this source, which is in the public domain: Sloane, T. O'Conor (1892). "Mordey Effect". The Standard Electrical Dictionary. New York: Norman W. Henley & Co.{{cite encyclopedia}}: CS1 maint: ref duplicates default (link)
• "William Morris Mordey". Grace's Guide. Retrieved 7 February 2026.
• Westrin, Theodor (1925). "Mordey, William". Nordisk familjebok (in Swedish). Vol. 38. Stockholm: Nordisk familjeboks förlags aktiebolag.
• "Re William Morris Mordey, deceased". The London Gazette. No. 34548. 6 September 1938. p. 5706.

• "Mordey and Dawbarn". Grace's Guide. Retrieved 7 February 2026.
• "Mordey-Victoria". Grace's Guide. Retrieved 7 February 2026.
• "Mordey-Fricker Electricity Meter Co". Grace's Guide. Retrieved 7 February 2026.
• "Mordey and Levin". Grace's Guide. Retrieved 7 February 2026.