Model 5

[Federalsignalmodel7]

I just got a model 5 siren and wanted to know how loud one of these things are with intake blocked. I want to test it without annoying neighbors. Thanks!

[fullsendersonly]

I just got a model 5 siren and wanted to know how loud one of these things are with intake blocked. I want to test it without annoying neighbors. Thanks!

if you don't want to annoy your neighbors just do a growl test. Blocking the intake could potentially damage the siren by overworking the motor and causing it to overheat. While some sirens have dampers to do a "Pulse" signal those sirens motors are usually more capable with the load put on the rotor and the increased air pressure. your siren was not made to do a pulse so if you are blocking the intake, please know it can damage the siren. also the Decibel rating is 107 Db at 100ft.

[HDN]

if you don't want to annoy your neighbors just do a growl test. Blocking the intake could potentially damage the siren by overworking the motor and causing it to overheat. While some sirens have dampers to do a "Pulse" signal those sirens motors are usually more capable with the load put on the rotor and the increased air pressure. your siren was not made to do a pulse so if you are blocking the intake, please know it can damage the siren. also the Decibel rating is 107 Db at 100ft.

Has motor selection for pulse variants been documented somewhere? I'm a bit skeptical that a siren manufacturer would swap in different motors for a coding add-on. That just adds more complexity to the siren manufacturer's supply chain. The duty cycle on these sirens is usually short anyway, so I don't think there'd be much of an issue blocking the intake to make it run quieter. But I probably wouldn't run my siren continuously for more than five minutes regardless.

For reference, I'm pretty sure the Thunderbolt 1003 uses the same chopper motor as the Thunderbolt 1000, and the 3T22 uses the same motor as the 2T22. But it may be possible that their motor selection was done with potential coding in mind.

[fullsendersonly]

if you don't want to annoy your neighbors just do a growl test. Blocking the intake could potentially damage the siren by overworking the motor and causing it to overheat. While some sirens have dampers to do a "Pulse" signal those sirens motors are usually more capable with the load put on the rotor and the increased air pressure. your siren was not made to do a pulse so if you are blocking the intake, please know it can damage the siren. also the Decibel rating is 107 Db at 100ft.

Has motor selection for pulse variants been documented somewhere? I'm a bit skeptical that a siren manufacturer would swap in different motors for a coding add-on. That just adds more complexity to the siren manufacturer's supply chain. The duty cycle on these sirens is usually short anyway, so I don't think there'd be much of an issue blocking the intake to make it run quieter. But I probably wouldn't run my siren continuously for more than five minutes regardless.

For reference, I'm pretty sure the Thunderbolt 1003 uses the same chopper motor as the Thunderbolt 1000, and the 3T22 uses the same motor as the 2T22. But it may be possible that their motor selection was done with potential coding in mind.

I'm pretty sure I read somewhere on air raid sirens wiki about it, but I could be wrong. and about the motors i think I was confusing something else with a coding motor, (controls the damper). because the motors are different depending on if they are 3 phase or single phase.

[HDN]

I'm pretty sure I read somewhere on air raid sirens wiki about it, but I could be wrong. and about the motors i think I was confusing something else with a coding motor, (controls the damper). because the motors are different depending on if they are 3 phase or single phase.

Absolutely. The other thing I was thinking of was 240V vs 480V motors. I'd think the 240V motors would run hotter due to needing more amps for the voltage, so maybe there's something to it there.

I'm glad you reminded me about the phases because I forgot about the different voltages too. So the Model 5 came with three different motors anyway - single-phase 240V, and three-phase 240V and 480V. With that in mind, I guess Federal Signal may not care about adding another motor option if they had to because they had so many already

Me and my modern supply chain mind

[Federalsignalmodel7]

Here's my thoughts. The motor is under a load so it spins a tad bit slower. If you block the intake and reduce resistance, the motor should spin at intended speeds. I'm not really sure if that's true or not.

[Darley Champion]

if the rotor spins in the correct direction (at least on sirens with directional vanes) it'll induce some drag which will slow down the rotor slightly (add tight rotor to stator tolerances to the equation and this'll exacerbate the effect). If you block the air intake, since there is little to no air going to it (there's still bound to be a tiny amount of air leaking through) the rotor will not be slowed down anymore. IIRC you can test this by taking a computer cooling fan and block it's intake, you'll hear it spin faster.


Now, none of this vane direction stuff applies for the Model 5 as it has non-directional vanes, although the damper part still applies. If anything it'll spin a tad bit faster and will have a longer wind down since there's no air dragging down the rotor.

In other words, you can safely block the intake, it won't hurt anything.

[Federalsignalmodel7]

Just did this with a high powered leaf blower.

Yes. The rotor does have a chunk missing.
https://drive.google.com/file/d/1dtfHVw ... p=drivesdk