Federal Signal 3T22
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The Federal Signal 3T22 and 2T22 are dual-tone, mechanical outdoor warning sirens made by Federal Signal Corporation (formerly Federal Sign and Signal Corporation) from 1952 through the early 1990s. Both have a very recognizable design, with a ten-port rotor (chopper) on the bottom with ten cones (horns) and a 12-port one on top with twelve cones.
History
[edit]The Federal Signal 3T22 was originally designed as the 2T22 in 1952 or 1954. The 2T22 has the same number of ports and cones. It can produce two main signals (it can produce more but the other signals are rarely used), hence the name "2T22" (the 2 at front representing the 2 choppers, and the 22 representing the amount of horns). The siren has no solenoids, so it cannot perform a "hi-lo" signal. In 1955, Federal designed the 3T22, which is similar, except for its name and that it has solenoids. The 3T22 is superior in design because it can perform the "hi-lo" signal, which is mainly used for fire calls. The 2T22 and 3T22 can produce 113db (measured 100 feet away from the siren). There are four models of this type of siren. the 2T22 A and B and the 3T22 A and B. In the name 3T22, the 3 stands for its three main signals: attack (wail), alert (steady), and hi-lo, and the 22 again stands for the twenty-two cones. The A or B determines whether the motor is three phase or single phase. A 3T22A is three phase, while a 3T22B is single phase. The siren was mainly used for air raid warnings during the Cold War era and weather warnings after the war. In the early 1990s, the siren's production was stopped when it was replaced with the newer 2001-SRN, which can reach 126db (also measured 100 feet away), hence the name. Like many other older siren models, these sirens are becoming more uncommon due to their age and because of newer technology.
Design
[edit]The 3T22 came in only one port ratio: 10/12. It has ten ports and cones on the bottom and twelve ports and cones on the top. It also has a smaller cone on top to reduce rain and other water-related substances such as snow from getting inside. It has two solenoid boxes, one on top, and one on the bottom. There are also two air intake spots: also one on the top and bottom. The siren has a small stand with three legs so it can be mounted on a pole or roof. The stand can be removed and the siren can be mounted differently.
References
[edit]http://civildefensemuseum.com/sirens/manuals/255A152H-2T22-3T22.pdf