Federal 500 siren

The '''Federal 500''' was a fire–air raid siren produced by [[Federal Signal Corporation|Federal Sign and Signal Corp]]. from 1950 to 1981.

==History==
[[Image:FEDERAL500.jpg|thumb|right|200px|Federal 500AT]]
The Federal 500 was introduced around 1950 as a non-rotating, one-phase, 5 HP motor fire siren. It was conceived from a rotating–horizontal Model 5. The siren was made as a three-phase 5 HP motor siren, due to better motor pickup capabilities. A rotator feature was also introduced not long after its premiere, due to better sound coverage. A 10 HP dual-tone version called the 500T came out in 1954, to fit Civil Defense standards for dual-tone sirens. Around 1960, the design was improved, with a longer projection dish and an improved motor cover. The siren's dual tone ratio was changed to a non-harmonic minor 3rd, instead of the previous 4th interval. In the mid 1970s, the design was changed once more to feature a 10 HP motor, and a 4th interval sound once again. The 500 was discontinued around 1981.

==Other variants==

The 550AT is a double-headed, rotating version of the 500T. It has a rotor and stator with 12 ports on one side, and another with 8 ports on the other side. This sounds as a 5th interval resultant.
Approximately fifty were manufactured before the 550AT model was discontinued in the early 1960s.
The 550AT used a 10-horsepower three-phase, dual-shaft motor.
All 550 AT installations located so far are installed with three-phase electrical service.
The 500C was a version of the 500 with a coding damper attached to the intake. It is unknown how many were produced, and none have been located as of yet.

== Cities using the 550AT siren==
{| class="wikitable"
|-
! City, State
! Status

|-
| [[Calhan, Colorado|Calhan, CO]]
| One was installed in 1959 at City Hall, and is currently still in service.
|-
| [[Colorado Springs, CO]]
| Several were installed in 1959, and removed in 1989
|-
| [[Manitou Springs, Colorado|Manitou Springs, CO]]
| One was installed in 1959, and is located at the police station, and is still serviceable.
|-
| [[Newark, New Jersey|Newark, NJ]]
| One was spotted near Newark, NJ. Status is unknown.
|-
| [[Saint Louis, Missouri|St. Louis, MO]]
| One was spotted in St. Louis. Status is unknown.
|-
| [[Sugar City, Colorado|Sugar City, CO]]
| One is located near Adams St. Still in service and used regularly.
|}

==Cities using the 500 siren==
{| class="wikitable"
|-
! City, State
! Status
! Type

|-
| Dundee, MI
| In use as fire department's siren
| 1960's, 10-12 ratio
|-
| Madison, WI
| 3 in use
| 1976, 9-12 port ratio
|-
| Marshfield, WI
| 1 in use, until around 2013
| 1970's, unknown port ratio
|-
| Los Angeles, CA
| Many installed, all out of use since 1986
| 1950's, 9-12 port ratio
|-
| Topeka, KS
| 1 still standing out of a former set of 6
| 1960's, 10-12 port ratio
|-
| Reedsburg, WI
| 1 in use for noon blast and fire department
| 1959, 12 port ratio
|-
| Byron, GA
| 1 still in use as a severe weather siren on water tower
| 1965, 10-12 port ratio
|}

==Technical information==

{| class="wikitable"
|-
! Years
! Type
! Motor HP
! Rotor/Stator interval
! Notes
|-
| 1950–1960
| 500A/B
| 5 HP
| 12, 7, or 8 port
| Originally non-rotating design
|-
| 1954–1960
| 500T
| 10 HP
| 9/12 port
| 120 dB at 100 feet
|-
| 1960–1976
| 500AT/BT
| 5 HP
| 10/12 port
| Loudest 500 at 123 dB at 100 feet
|-
| 1976–1981
| 500AT-240
| 7.5–10 HP
| 9/12 port
| Also was available as a 12-port siren

[[Category:Sirens]]