Edison New Type 1893-1899

During the late 1880s an early 90s, Edison lamps underwent numerous improvements and design changes, with a new version being introduced practically every year. The situation stabilised somewhat following the introduction of the so-called "New Type Edison Lamp" featured on this page, which remained in production during the period 1893-1900.

Prior to 1893 all Edison lamps employed filaments made from carbonised bamboo, a notoriously difficult material that introduced large variations in performance owing to the irregularity of this natural fibre. In 1893 the Edison factories adopted the squirted cellulose filament, a man-made carbon fibre of tremendously improved strength and uniformity.

The platinum sealing wires originally penetrated the entire stem press. In 1889/90 the length of platinum was reduced to a minimum of 1/8" by welding to copper wires, the welds also being embedded in the press seal. This necessitated extra work in forming the delicate welds, a process which was superdeded in 1892-94 by the construction featured here. The inner copper wire was omitted, with the platinum section being connected directly to the filament.

The method of connecting the platinum leadwires to the filament is with a carbon paste, as introduced in 1886 to supersede the former copper plated joints. The base is of a type introduced in 1888 in which the number of threads was increased, refined in 1893 to the shape shown here. It was superseded only in 1890 when a more durable porcelain insulator replaced the Plaster of Paris employed in this lamp. The bulb envelope has been blown into a mould rather than in free air, a technique first introduced in 1892.
Manufacturer: Edison General Electric
Lamp Power: Approx 75 Watts
Lamp Voltage: 107 Volts
Lamp Current: 0.63 Amperes
Cap Type: Edison Screw Flat end 1893-1900 style
Bulb Type: SA-56 SA-18 in eighths/inch
Bulb Finish: Clear Soda-lime glass
Filament Type: Carbonised squirted cellulose
Atmosphere: Vacuum No getter
Luminous Flux: 201 lm 16 Candle Power
Luminous Efficacy: 2.7 lm/W 4.7 Watts per Candle
Beam Intensity: N/A
Beam Distribution: N/A
Colour Temperature & CRI: CCT: 2000K CRI: Ra 100
Chromaticity Co-ordinates: CCx: 0.527 CCy: 0.413
Rated Lifetime: Approx 800 hours
Burning Position: Universal
Overall Length: 127mm 6 inches
Light Centre Length: 83mm 3ΒΌ inches
Factory: Harrison, N.J. U.S.A.
Date of Manufacture: 1893-1899
Original / Present Value: Unknown Unknown
 
References: 1) The History of the Incandescent Lamp, J. Howell & H. Schroeder, The Maqua Press, 1927
2) The Incandescent Electric Lamp 1880-1925, E.J. Covington, NELA Press, 1988
3) Pictorial History of the Edison Lamp, Edison Lamp Works of General Electric Co., Circa 1915