power consumption for a 100 watt siren question

[bpollard]

I know that there may be some variations from one manufacturer to another, and age/vintage versus modern.

My question is, what should a 100 watt siren draw at 12-14 volts DC?

In electrical terms, amps= wattage/voltage (good ole OHMs law). But I am not sure if that applies. Does the number "100" in 100 watt mean electrical load or is it an audio thing?

Bob

 

[Sparky_911]

Typically the 100 watts is audio output not 12vdc power consumption. The amp rating usually means 12vdc power consumption. The key to a good siren/speaker combination is to make sure the polarities are correct amd the ohms of the speaker matches the ohms of the siren head.

 

[ur20v]

Federal Signal claims the Touchmaster sirens draw 7.5A when using one 100W speaker, 14A connected to two 100W speakers.

Whelen's HHS2200 siren draws 16A "max" when wired to two 100W speakers.

It's probably safe to assume most 100W sirens draw around 8A or around 16A at 200W. Its possible newer, more modern sirens may have more efficient digital amps that draw less current with similar output wattages.

Also keep in mind a siren tone is a pure signal (unlike music or voice recording), so the output wattage is constant, therefore the current draw is constant. Using the PA is a different story...

 

[CHIEFOPS]

As a rule of thumb I've always estimated a 100 watt siren in operation to draw a minimum of 8 amps. I don't believe most sirens' PA function broadcast 100 watts so if I'm right it must draw even less amperage.

 

[JohnMarcson]

People usually install fuses not more than 125% greater than the anticipated load. As stated a 200 w siren is around 16 amps so it is common to ue a 20 amp fuse.

 

[bpollard]

thanks guys!