Manfacturer: GTE Sylvania
This Sylvania 400 watt mercury vapor lamp is quite old, around 30 years old and exhibits the flat, fabricated arc tube support. Sylvania used this fabricated support from 1969 through 1975, and the reason this was used was to reduce the number of welds required in an arc tube support. Often welds would break, rendering the lamp inoperable. But with fewer welds/connections, the risk of a broken contact, etc is much lower in this lamp than other HID lamps. The drawback to this design is that light output was reduced a little due to the thick frame blocking out a little light. Lamps like this are sought among HID and streetlight collectors due to its age and design, as well as lamps like this tend to last well over 100,000 hours in some cases. This lamp still lights and casts a slight seaweed greenish appearance at full brightness, which actually still puts out quite a lot of light.
UPDATE 3/1/03: This one turns out to have been manfactured in 1975, clearly the last year for the fabricated arc tube support frame. By 1976 Sylvania had redesigned the arc tube support to be made of simple, thick wires like most HID lamps.
The above pic is the close up of the same lamp's arc tube. Note the lines in the quartz. This was a common trait among older lamps due to the way they were manfactured at the time. Today's lamps have arc tubes with improved manfacturing processes that elimanted the lines...and even after thousands of hours newer arc tubes will not show the lines.
Lamp: Mercury Vapor
Wattage: 400 watt
Starting Voltage: 240 volts
Operating Voltage: 130 volts
Ballast Type: H-33
Color Temperature: 5700 degrees K
CRI: 20
Light Output: 21000 Lumens
Bulb: BT-37
Finish: Clear
Base: E-39s Nickel Plated Mogul Base
Class: -
Filament: -
Lamp Life: 24,000 hours
Manf. Date: May 1975
Country of
Orgin: USA
