Motor driven siren has high volume 123.3dB, working voltage 3 phase 380VAC, rated power 2.2kW (3 hp) and two-way alarm mode.

Specification:

Tips: 3 alarm modes of motor driven siren
The motor driven siren is mainly used for air raid alarm system. According to specific provisions for air defense warning signal test, there are three alarm modes for air raid alarm.
Pre-alarm: Alarm 36 seconds, stop 24 seconds, last 3 minutes.
Air raid alarm: Alarm 6 seconds, stop 6 seconds, last 3 minutes.
Release alarm: Continuous alarm for 3 minutes.
When the air-raid siren stopped, it actually still makes a sound. A low-frequency humming sound is still made due to the inertia of the motor rotor. For example, pre-alarm is alarm for 36 seconds and stop for 24 seconds. In fact, what you hear is that the sound is higher in 36 seconds and lower in 24 seconds.
Under modern air strike conditions, sometimes air raid alarms may be issued directly, so everyone must learn to distinguish the alarms, not only can understand the air defense alarm signals, but also strive to identify them as soon as possible and make corresponding protective actions.