This is a Q that has not run in 40+ years. I had the rotor, stator housing and clutch assembly but everything else has been collected over this last year. Here it is in the "nude", without grill and motor cover on its first test run.
No, I think the curved blades were an attempt to draw more air thru the siren. Look at the blades on a turbocharger compressor wheel to see what I am saying. The coast time is determined by the condition of the rotor bearing, the balance of the rotor and correct clutch disengagement. If you were to block the airflow to the siren it would coast for a very long time. Look at my "B&M S8B Siren Restoration" video to see what happens when you block the air intake.
The M30 has a smaller dia. rotor but Sterling elected to add mass to the aluminum rotor by riveting a steel plate on the face of the rotor and use the term "free rolling" in the Model description.
I use the 2 8D batteries because they are available to me, by no means are they required. Most automobile batteries can furnish 600-1000 CCA (cold cranking amps) for short periods of time. In this video it is powered for approx. 5.5 seconds, in my other Q video, 14 seconds, a regular car battery would give many minutes of noise.
So that's what the old fire trucks had. I noticed that the holes on the side reminds me of Air Raid Sirens like Castle Castings for example or Carters. I also like how the blade looks too. :)
Beautiful spiral in the chopper fan. I call them chopper fans because they are what force the air through the chopper. Idk what they are really called tho.
Yes you could. Back in the late 1950's thru 1970's, before the electronic siren became easily available, you could see these Q's and other mechanical sirens used on many type of vehicles including cars. Search on RU-vid for "Jeep Q Siren" and you will see it is not a problem.
I have access to a portable arrow board warning sign like you see on highway construction sites. It has 2 8D 12 volt batterys in parallel that I use as a power source, but any 12 volt automobile battery would give several minutes of run time.
Question. Do the blades inside the rotor have to be curved to help with the long wind down?? I know the clutch in their or disconnects the motor from the motor and the rotor spins freely, but do the curved rotor blades help?? Nice siren by the way.
Understood. Always wanted to know. But does the M30 rotor have smaller diameter and less "inertial mass" so that it slows faster, anyway? Though I have replaced starter motors, I don't recall ever trying to turn one to discern the drag. I didn't know there was more pressure on high amperage brushes. Thank you.
Watch the video of my Sterling M30, it is direct coupled with no clutch, the coast time is considerably shorter than a clutch equipped siren. The motor brushes have high spring pressure because of the large current draw which creates drag.
Excellent! I like it better without the cover. Probably a little louder without the grill and stator port ribs. Federal's rotor is a work of art. Should not be hidden. I would paint an inward spiral on the rotor fins. (A paint which could be removed if desired.) Have you tried reversing polarity and spinning it the opposite direction? Nice, sharp, steady video. Thank you.
Oh. Forgot about the clutch. Thanks. What if you defeated the clutch? Would the motor slow the rotor noticeably faster? Still, in use, no need to keep the motor spinning directly coupled to the rotor and wearing the motor brushes. Thank you.
Great thing about rotary sirens is they don't waste a lot of power revving up, and no power at all revving down, yet they still make sound when revving down, so it's really a win-win
When I was a rookie I noticed numbers on the fins of the Q siren...When asked about it the Shift Commander told me the old Guys would play Routlette...Thats when there was EMS and more down time I guess...
Go to Federal Signal website, look up the Q siren, download exploded parts list for your model siren, select brake parts you need, jot down part number and order thru a Federal Signal distributor.
Thats the clutch working as it should. The higher end sirens from most companys sold coaster sirens that incorporated a clutch. When power was removed, the rotor continued to coast, producing sound and saving on electrical
years back I was on a volunteer rescue squad it was an old van type ambulance and we had one of those mounted on the roof now we did have a 200w electronic sign but nothing would get the traffic out of the way like that big beast of a siren we also had it on another truck and the knob on a code 3 run fell off the electronic siren so we had to run that big beast we're traffic pulled over for 2 miles in front of us nice straight shot no traffic whatsoever everybody was getting up on the curb
I would reverse the DC to make the rotor spin in the opposite direction. Would be.tter withalf the ports. Lower frequencies travel further and penetrate vehicles better.
Cannot reverse a series wound starter motor without major modifications. Simply swapping pos. and neg. leads will not work. Also the clutch would never engage the rotor but it would be an interesting experiment.
