Tantalum Filament Lamps

The tantalum filament lamp was developed by Drs. Werner von Bolton and Otto Feuerlein of the Siemens-Halske Company in Berlin. The first lamp that withstood photometric and life testing was completed on Dec 28, 1902. That lamp had a looped shape filament. In Jul 1903 the first tantalum filament lamp was obtained with a wire diameter of about 0.05 mm. It too had a loop filament. The first serviceable lamp for 110 volts was produced in Sep 1903.

The General Electric Company and the National Electric Lamp Company acquired the exclusive rights to manufacture the lamp in the United States on Feb 10, 1906. The first lamp bulletin regarding the tantalum lamp was issued by National on Jan 14, 1907. The first lamp made was a 44-watt design at 22 c.p. and 100-130 volts. By Nov 9, 1907 three new tantalum lamps had been added to that one. The tantalum lamp line then consisted of two sizes in straight sided bulbs and two sizes in round bulbs. Tantalum lamps were described in bulletins up to November 20, 1910. In the following most of these lamps are represented. Descriptions are given following the images.

1) 20 c.p., 42 watts, 100-125 volts, bulb dia.= 2-3/8 inches, lamp length= 5 inches.

2) 40 c.p., 80 watts, 100-125 volts, bulb dia.= 3-1/16 inches, lamp length= 7 inches.

3) 20 c.p., 40 watts, 100 to 125 volts, bulb dia.= 2-5/16 inches, lamp length= 5-1/4 inches.

4) 50 watts, 200-250 volts, bulb dia.= 3-1/16 inches, lamp length= 5-1/8 inches.

5) 25 watts, 100-125 volts, bulb dia.= 2-3/8 inches, lamp length= 5 inches.

6) 80 watts, 100-125 volts, bulb dia.= 5 inches, lamp length= 7-5/8 inches.

7) 40 watts, 100-125 volts, bulb dia.= 3-3/4 inches, lamp length= 6-1/8 inches.

8) 80 watts, 200-250 volts, bulb dia.= 5 inches, lamp length= 7-5/8 inches.

9) train lighting lamp, 28-34 volts, 8 or 12 c.p., 16 or 25 watts, bulb dia.= 2-5/16 inches, lamp length= 3-1/2 inches; 57-65 volts, 12 c.p., 25 watts, bulb dia.= 2-5/16 inches, lamp length= 3-1/2 inches.

10) train lighting lamp, 28-34 volts, 8 or 12 c.p., 16 or 25 watts, bulb dia.= 2-1/8 inches, lamp length= 4-1/4 inches; 57-65 volts, 12 c.p., 25 watts, bulb dia.= 2-1/8 inches, lamp length= 4-1/4 inches.

11) train lighting lamp, 57-65 volts, 20 c.p., bulb dia.= 3-3/4 inches, lamp length= 6-1/8 inches; 28-34 volts, 40 c.p., 80 watts, bulb dia.= 5 inches, lamp length= 7-5/8 inches; 57-65 volts, 40 c.p., 80 watts, bulb dia.= 5 inches, lamp length= 7-5/8 inches.

12) headlight or side-light for electric vehicles, 28-34 volts, 16 watts, bulb dia.= 2-5/16 inches, lamp length= 3-1/2 inches; 28-34 or 57-65 volts, 25 watts, bulb dia.= 2-5/16 inches, lamp length= 3-1/2 inches.

13) 40-watt tantalum lamp in (Type B) Bowl Holophane Reflector.

14) 40-watt tantalum lamp in (Type C) Concentrating Holophane Reflector.

15) 40-watt tantalum lamp in (Type D) Distributing Holophane Reflector.

16) 40-watt Meridian tantalum lamp in Type S-1 Holophane Reflector.