I’ve decided to come up with a comprehensive system for classifying and describing electromechanical alarm signals based on how they work.
Note that the difference between a “horn” and a “buzzer” in this classification system is that a buzzer will produce a set frequency when powered by AC (even though DC models are still buzzers), but motor horns and resonating horns will maintain an independent frequency.
[quote]Solenoid-Driven:
Bell - Hammer strikes a thick metal plate. Single-stroke or vibrating.
(Examples: Simplex 4080, Edwards Adaptabel, Wheelock 46T)
Chime Bar - Hammer strikes a rectangular bar. Single-stroke or vibrating.
(Examples: Autocall Executive, Simplex 2902-9234, Edwards 339, mechanical doorbells)
Reed Buzzer - Metal reed rapidly taps directly against electromagnet contact.
(Examples: Faraday 7410, Edwards Dixie Buzzer, most dryer buzzers)
Flat Buzzer - Hammer rapidly strikes a thin metal diaphragm.
(Examples: Simplex 2901-9838, Wheelock 34T and 31T, Federal Vibratone 450)
Hi-Hat Buzzer - Cymbal-like diaphragm rapidly oscillates against metal plate. Generates residual wind.
(Examples: Edwards Adaptahorn, Federal Vibratone 350, most vehicle horns)
Resonating Horn - Airtight diaphragm forces air through extremely narrow space.
(Examples: Federal 53, 55, and some types of locomotive horn)
Motor-Driven:
Motor Bell - Rotating motor drives bell striker. Vibrating only.
(Examples: Amseco MBA, Wheelock MB, System Sensor SSM)
Motor Horn (Klaxon) - Rotating motor drives toothed cogwheel against metal diaphragm.
(Examples: Amseco BZ-54VT, submarine diving horns)
Motor Siren - Rapidly spinning blade forces air through small side ports.
(Examples: Federal Signal Models A and B9, Master Blaster, civil defense sirens)
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