Norelco SON-T American Design
During the 1970s Philips diversified in its manufacturing of High Pressure Sodium lamps, and opened a second production facility at the Hightstown factory in New Jersey, USA. This was formerly the incandescent and mercury discharge factory of Radiant Lamp Co., which was acquired by Philips during the 1960s. The arc tubes were supplied by the Philips HID mother factory in Belgium, and finished into lamps in USA according to the differing bulb and base requirements of that market.

It is interesting to note that the American-made lamps differ somewhat in design from the European production. Most significant is the original range of wattages that was produced. In addition to the standard 250W version featured here there was also a 400W lamp of equivalent design, in the same clear outer envelope. But these were joined in 1973 and 1974 by two new low wattage lamps having the unusual ratings of 175W and 125W, equipped with diffuse ellipsoidal bulbs of 70mm and 75mm diameter respectively. Very little information is available on these unusual ratings, which were discontinued within two years and replaced by 150W and 100W types, however it is believed that they were intended for operation on mercury lamp ballasts. The non-optimised design would have limited system efficacy and is perhaps a reason for their rapid disappearance.

Incidentally Philips was unable to use its brand name in North America, owing to the existance of a local competitor in the same business and with the similar name "Philco". Consequently from the 1940s up to 1981 when it eventually acquired Philco, Philips traded under the brand "Norelco", derived from "North American Philips Electrical Company".
Manufacturer: North American Philips Lighting Co.
Lamp Power: 250 Watts
Lamp Current: 3.0 Amps
Lamp Voltage: 100 Volts
Cap Type: E39s/41 (Mogul) Ni Plated Brass + Vitrite
Bulb Finish: Clear Lead Borosilicate
Bulb Type: ET-57 ET-18 (in eighths/inch)
Overall Length: 257 mm 10 1/8 inches
Light Centre Length: 160 mm 6 1/4 inches
Arc Length:
Electrodes: Backwound tungsten BaCaY emitter
Atmosphere: Inner: Hg,Na | Xe Outer: Hard Vacuum
Luminous Flux: 25,500 lm @ 100 hours
Luminous Efficacy: 102 lm/W @ 100 hours
Colour Temperature & CRI: CCT: 2000K CRI: Ra 23
Chromaticity Co-ordinates: CCx: 0.526 CCy: 0.418
Burning Position: Universal
Rated Lifetime: 20,000 hours to 50% survival
Warm-up & Re-strike Time: 4 minutes 15 minutes max.
Factory: Hightstown, NJ U.S.A.
Date of Manufacture: September 1980 Date Code J0
Original & Present Value: Unknown
 
References: 1) Norelco Advertisement in "The American City", November 1973, pp.94-95