Editing Civil defense siren (section)

==== Supercharged ====
A variation of the electromechanical siren is a ''supercharged'' siren. A supercharged siren uses a separate source, usually a [[supercharger]]-like [[Blower fan|blower]], which forces air into the rotor assembly of the siren. This increases the [[Pressure|air pressure]] in the rotor assembly, causing the sound output of the siren to increase heavily, which in return increases the sound range by a large amount. The blower is generally driven by an electric motor, but in rare cases it is driven by an [[engine]]. [[Federal Signal Corporation|Federal Signal]] took advantage of this design and created their [[Thunderbolt (siren)|Thunderbolt Siren Series]], utilizing [[Sutorbilt]] [[Roots Blower]]s of different varieties and outputs.<ref>{{Cite AV media|title=Sutorbilt 4M Blower Test|date=30 July 2021|url=https://www.youtube.com/watch?v=zwE0w7jQkPE|access-date=2023-09-02|language=en|via=[[YouTube]]}}</ref><ref>{{Cite AV media|title=Testing a Thunderbolt siren C-series blower|date=6 September 2009|url=https://www.youtube.com/watch?v=D04jpC2hr8Q|access-date=2023-09-02|language=en|via=[[YouTube]]}}</ref><ref>{{Cite AV media|title=My Thunderbolt 1000BT Blower Test|date=24 February 2020|url=https://www.youtube.com/watch?v=KnDOO9UyDwE|access-date=2023-09-02|language=en|via=[[YouTube]]}}</ref><ref>{{Cite AV media|title=Series A1 (6M) Thunderbolt blower run|date=25 June 2014|url=https://www.youtube.com/watch?v=IbkVQgk1ro4|access-date=2023-09-02|language=en|via=[[YouTube]]}}</ref>

A very early model called the Thunderbolt 2000. The difference between the Thunderbolt 2000 and later editions is that its blower is driven by an [[Cummins|Onan]] two cylinder gas engine.<ref>{{Cite web|title=Thunderbolt Siren Series|url=https://wiki.airraidsirens.net/Thunderbolt_Siren_Series|access-date=2021-10-08|website=Air Raid Sirens Wiki|language=en}}</ref> Another example of a siren that has a separate blower is the [[Alerting Communicators of America]] (ACA) [[ACA Hurricane|Hurricane]]. One more example of a siren with a blower is the [[Southern California|SoCal]] Edison Model 120, utilizing a Centrifugal Style Blower, built specifically for the [[San Onofre Nuclear Generating Station]]. The SoCal Edison Model 120 is no longer standing out in public, as only one exists, and is owned privately.<ref>{{Cite web|title=Model 120|url=https://wiki.airraidsirens.net/Model_120|access-date=2021-10-08|website=Air Raid Sirens Wiki|language=en}}</ref>

[[File:SoCal Edison Model 120.jpg|thumb|A SoCal Edison Model 120 illuminated by a spotlight in the night sky in 2003. They were manufactured in-house by SoCal Edison and were installed in 1982 for use with the [[San Onofre Nuclear Generating Station]] Community Alert Siren System. The blower is located in the middle just above the mounting plate hidden within the mesh bird screen between the frame support structure for the horns.]]