Motor driven sirens are a typical style of an audible signal. They work by the motor driving a bladed impeller, pulling in air and pushing it back out through vents to produce a whirring sound – similar to an air raid siren. These units are commonly used in remote areas where a distinct noise it required to warn of an emergency.
Motor driven sirens usually have a duty cycle; for example 5 mins on and 10 mins off, so be sure to check this suits your application before using one.
As with all audible signals, these sirens have many pro’s and con’s:
Pro’s
– Tend to be lower priced due to a simpler design.
– Lower frequency which travels better through and around object.
– Good to use in remote areas or in an area where electronic tones are used for fire alarms, and a siren is required to warn of something else.
Con’s
– Is only single tone and has no volume control.
– High current draw and low efficiency.
– Lower IP rating due to the exposed blades which can get blocked with dust and debris.
