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STH-10/STL-10

Posted: Fri Jan 12, 2007 1:40 am
by pyramid head
What is the difference between these two sirens? The only thing i noticed was one of them had more projectors. So more projectors= more ports is what i guess is the alteration.

Posted: Fri Jan 12, 2007 1:50 am
by Whelen Rules
The STL-10 which is my favorite federal siren of all time, has a lower pitch than the STH-10 STL= Special tone low STH-10= special tone high

Posted: Fri Jan 12, 2007 2:00 am
by pyramid head
Oh, ok thanks for clearing that up for me! I have noticed that there are sirens in models"a" and "b" which is for motor power(single/three phase) does the three phase power have something special about it? All sirens were made to use it, so it seems. Single phase would be a lot better seems how you wouldn't have to do different wiring, and use just about all other house hold things with it. Does three phase use more energy?

Posted: Fri Jan 12, 2007 2:20 am
by Brendan Ahern
Three phase is more efficient. If you tried running a 10HP motor on 120 volts, you would be pulling a lot of amps. With 3 phase you are lowering the amps by raising the voltage. Like a hose and a power washer. If you wash something with a garden hose, you are in theory going to need more water then if you used a pressure washer. Not the best analogy in the world but the first one that comes to mind. In the building I work in, every piece of major equipment is 480V 3 phase. Pumps, air handling units, exhaust fans, the compressor. Everything except the boilers, which use 120. Even some of our lighting is 277, not much, but some. You have to watch for that, trust me, you dont want to accidentally put a 120V ballast into a 277V fixture.hahaha

Posted: Fri Jan 12, 2007 5:32 am
by Daniel
I believe that both sirens have the same motor and the same rotor diameter. The STH-10 has 12 ports while the STL-10 (sometimes labelled STL-7) has 7 ports, which makes it almost an octave lower. Both sirens run at 3,450 RPM and have a fairly slow rise and fall, but the STL seems slower because it has less of a musical scale to climb.

Posted: Fri Jan 12, 2007 7:35 pm
by pyramid head
I have seen two sirens that look like they are part of the STX-10 series, i will try to figure out which they are when i get my permit and take pics. Also i will be taking some pictures of our local fire department's siren, a blue model 3. 8) Five days remain untill i am 16 :D

Posted: Mon Jan 22, 2007 1:28 am
by pyramid head
Does the STL-10 have a very slow and low sound to it?

Posted: Mon Jan 22, 2007 1:37 am
by holler
Could someone post a recordings of both for a comparison? I've heard a STH-10 before but never a STL-10.

Isn't the Thunderbeam based on the STH-10?

Posted: Mon Jan 22, 2007 2:50 am
by Trey
holler wrote:Could someone post a recordings of both for a comparison? I've heard a STH-10 before but never a STL-10.

Isn't the Thunderbeam based on the STH-10?
Here is an STL10 recording: http://www.longislandfirealarm.com/Mill ... -Sig16.wma

Yes the Thunderbeam is the rotational version of the STH10.

Posted: Mon Jan 22, 2007 3:02 am
by holler
Thanks for the recording.

That is one more freaky windup sound. Sounds like a Budweiser frog getting squeezed to death.