These are basically formed by an electric motor with a specially treated head that emits a sound while rotating. Even now these sirens are used in many countries. The development of electronics, however, has also influenced this area and first electronic sirens started to appear at the end of the 20th century. Electronic sirens are basically high-performance sound signal electronic amplifiers just like those in home sound systems. However, these sirens work with substantially higher outputs and specific demands are placed on them in terms of desired extreme reliability and different methods of their control. Control infrastructure must also be reliable and usually two independent control channels are required. The loudspeakers for these amplifiers are placed in specially-designed sound baffles and they play the signals stored in the siren’s digital memory or signals fed to the siren from external sources – a microphone, phone, radio station, common radio and television broadcasting, etc. Telegrafia currently offers two product lines of state of the art electronic sirens: PAVIAN and GIBON.
Main advantages of electronic sirens
- Standard operations use batteries that are continuously recharged.
- They are capable of reproducing not only warning signals but also voice announcements.
- It is possible to add an external signal source – a microphone, phone, radio station, radio, etc.
- They provide enhanced automatic testing functionality – potential failure is not discovered as late as at the movement of potential use; it is discovered in advance and can be eliminated in a timely manner.
Main disadvantages of motor-driven sirens
- They have high power consumption and require continuous electric power supply – no battery-based operation is possible or backup power sources would be disproportionally expensive.
- They are only capable of generating tones at a certain frequency or oscillating tones; no voice announcement is possible.
- Manual operation.