Westinghouse Brake and Saxby Signal Co., Ltd.
82, York Road, London, N.1. (1918)
82 York Way, Kings Cross, London W.1. (1934)

Westinghouse Brake & Signal Company
82 York Way, Kings Cross, London W.1. (1935)
Pew Hill House, Chippenham, Wiltshire (1945)

Brands: Westector, Stedipower, Westalite, Westeht, Stabilistor.

Westinghouse Brake & Saxby Signal Company, later Westinghouse Brake & Signal Company, was a major British manufacturer that became a pioneering force in the development and production of metal rectifiers from 1925 onward, introducing copper oxide and later selenium rectifiers for converting AC to DC. Their rectifiers were widely used in radio apparatus, battery chargers, and battery eliminators, helping to popularise mains-powered radios and supporting the growth of the domestic radio industry in Britain. The company’s innovations in rectifier technology established it as a key supplier of electrical components beyond its railway origins, with its products remaining influential in radio and industrial applications for decades.

Radio and Rectifier Innovations (1920s–1930s)

Expansion into Radio and Rectifier Technology
While Westinghouse Brake and Saxby Signal Co., Ltd. (WB&SS) built its reputation on railway brakes and signalling, the 1920s and 1930s saw the company become a notable innovator in radio power supplies and rectification. This diversification was both a response to the growing domestic radio market and a natural extension of the company’s expertise in electrical engineering.

Dry Metal Rectifiers: A New Era

By the late 1920s, WB&SS was producing dry rectifying units-a significant advance over earlier wet or paste-based rectifiers. These “dry” units, using solid chemical materials, were safer, more reliable, and required less maintenance, making them highly attractive for radio constructors and enthusiasts.

• 1928: The company introduced a special Westinghouse dry rectifier for the Stedipower LT Unit, a popular low-tension (LT) power supply for radio sets. Unlike the rival Kuprox unit, the Westinghouse rectifier had unique electrical characteristics, prompting transformer manufacturers to offer compatible models [1].
• 1929: At exhibitions, WB&SS showcased a broad range of dry metal rectifiers for both LT and high-tension (HT) charging. These units enabled radio users to eliminate batteries, offering efficient, noiseless, and compact solutions for home radio construction. The company published the “All-Metal Way” booklet, guiding users in building their own chargers and eliminators [2].  

Product Development and Technical Leadership

• 1931: WB&SS registered the Westector trademark (No. 524,147), a solid-state detector diode designed for radio receivers, marking its entry into the component market [3].
• 1932: The company expanded its HT rectifier line with the H.T.9, H.T.10, and H.T.11 models, designed for voltage-doubling circuits. These provided full-wave rectification with single-winding transformers, simplifying radio power supply design. The H.T.11, for example, delivered up to 500V DC at 150mA-an impressive output for the era [4].
• 1933: New models like the H.T.12 (30mA at 200V) and H.T.13 (for advanced receiver circuits) replaced earlier designs, reflecting ongoing refinement [5].

Radio Receiver Design and the Westector

• 1933: WB&SS published detailed construction guides for their new battery superheterodyne receiver, designed specifically to utilise two Westector diodes. This “all-metal” receiver featured advanced amenities such as automatic volume control, pentode output, and battery economiser circuits. The company did not manufacture these sets themselves but supported home constructors with comprehensive instructions and diagrams [6].
• The Westector was featured as both a second detector and in battery economizer circuits, showcasing the company’s commitment to innovation in solid-state radio technology [6].

Market Position and Impact
During these years, WB&SS’s rectifiers and radio components gained a strong reputation for quality and innovation. Their metal rectifiers were widely adopted for both home and professional use, and their technical literature helped foster a generation of radio enthusiasts and engineers.

The company’s radio and rectifier business, while a sideline compared to its railway operations, demonstrated the breadth of its engineering capabilities and its ability to adapt to new technological landscapes.

Radio and Rectifier Innovations Post 1933
After 1933, Westinghouse Brake & Signal Company significantly expanded its metal rectifier product line, building on its early copper oxide and selenium rectifier expertise. The company introduced several branded products-most notably Westalite, Westeht, and Stabilistor-which became widely recognised in both industrial and consumer electrical markets.

Westalite: This was the brand name for a series of selenium rectifiers produced by Westinghouse. Selenium rectifiers provided higher voltage handling and improved reliability compared to earlier copper oxide types. Westalite rectifiers were used extensively in battery chargers, radio power supplies, and industrial equipment, and their robust, finned designs became a familiar sight in British electronics through the 1950s and 1960s [7].

• Westeht: A line of high-tension (HT) rectifiers, optimised for applications requiring higher voltage and current capabilities. These units further cemented Westinghouse’s reputation for providing reliable, maintenance-free rectification solutions for both communications and industrial power systems [8].
• Stabilistor: This product line focused on AC voltage stabilisation and regulation, designed to deliver a stable, undistorted AC output voltage for single-phase 50 Hz applications, even under wide variations in input voltage (190–260 V) and load (no load to full load). Stabilistor units were important for sensitive radio and laboratory equipment, offering improved performance and protection for electronic circuits.

Technical and Market Impact

Westinghouse’s post-1933 rectifier products were characterised by their rugged construction, efficient heat dissipation, and adaptability to a wide range of electrical applications. The company continued to innovate, eventually moving into germanium and silicon semiconductor diodes and thyristors by the late 1950s and 1960s, but its Westalite, Westeht, and Stabilistor brands remained staples in the British and international markets for decades.

The Chippenham plant remained the centre of rectifier and semiconductor manufacturing, and Westinghouse’s products were listed in major reference works such as the Wireless World Radio Valve Data books well into the 1960s, reflecting their ongoing relevance and adoption in the rapidly evolving field of electronics.

Legacy
The Westinghouse Brake and Saxby Signal Co., Ltd. was not only a leader in railway technology but also a significant contributor to the early development of radio power supplies and solid-state rectification in the UK. Their Westector diodes and metal rectifiers were widely used and respected, and their educational efforts helped democratise radio construction during the golden age of wireless.
These innovations, though eventually overshadowed by the company’s core railway business and later corporate changes, remain a testament to Westinghouse’s role in the evolution of British electrical engineering.

[1] Wireless Constructor, Oct 1928, Page 371.
[2] Wireless Constructor Oct 1929, Page 388.
[3] Electrical Review Aug 21, 1931, Page 303.
[4] Wireless World Aug 12, 1932, Page 130.
[5] Electrical Review Aug 11, 1933, Page 193.
[6] Practical Wireless Dec 16, 1933, Page 714.
[7] Radio Constructor Aug 1953, Page 609.
[8] Electronic Engineering May 1948, Page 144.