General Electric conical-rotor siren

[Daniel]

This is an old siren built by General Electric sometime between WWI and WWII, according to this site. It is in Larkspur, CA, and I have never seen another siren quite like this one. Are any of these still in use? Where is the air intake?



http://www.ci.larkspur.ca.us/FireHornSl ... how10.html

[SirenMadness]

Weird.

Looking at the rotor, the air-intake seems to be the space between those ribs. The base for this siren is just HUGE!

[Robert Gift]

Could the air intake be those red square openings [ ] [ ] [ ] just below the motor,
which appear shut at the moment - maybe to keep out animals?
Perhaps a solenoid opens the openings.

The rotor is the cone shaped object athentrance to those
flaring projectors?

I wish the photo were taken much closer - filling the whole frame.

Fascinating!
Also enjoyed seeing the diaphone photos, one with it's manual overide valve just below the horn.

Thank you,

[SirenMadness]

The rotor is the thing with the red squares shown.

[Robert Gift]

The air is drawn in at the cone shaped part at the bottom
and chopped through the red stator openings at the top just below the motor?

That makes much more sense, but why the flared cones at the bottom?
Too bad the stator ports are blocked by the rotor.

Thanks for correcting me.

[SirenMadness]

You're welcome.
The flares are there for stability, so you can put the siren on something, suggestively a roof, easily, without having to buy a new base.

But don't worry, it took me some time to find the rotor, too.

[Daniel]

It's hard to tell whether those square sections are actually closed ports or just square depressions moulded into the stator. If they are indeed ports, then there is nothing at all in the conical part except a six-way projector and air intake. At first it appeared that there was a conical rotor inside, but looking again, the space inside the horns could be simply empty. This is just another example of a siren with a projector on the intake rather than on the ports. It would be interesting to find out the ratio of sound output from intake versus exhaust on any siren. My guess is that sound comes strongly from both, but more sound from the exhaust (ports) side.

[Robert Gift]

There sure appears to be a rotating something there, which happened to park misaligned with the "projector" intake. Notice that it is not even.

That museum should open the siren portso people can better understand how it works.

I didn't know anyone tried using the intake to emit meaningful sound.

Years ago I suggested to FedSig thathey draw air from behind the Q
rotor instead of the front where slush and sand and debris can more easily enter. I suggested it would also help cool the motor - it that was ever an issue. Then, they could put a big light in the front.

The Chinese siren I found pulls air up from beneathhttp://www.lksos.com