Vintage syren electrics

[SCP01]

Now that is nice! Even though the wiring and terminals look modern for the cost of a pint I would let an electrician over here cast his eye over it. Serviceable or not I would preserve rather than condemn though. Do you have a 3 phase supply for when crank up time arribes?

I was involved with a museum on an ex RAF / USAAF base until fairly recently but the old siren system had long been replaced and there were only a couple of Castle Castings sirens about the place. You are a lucky man

[Daniel]

Robert, if the siren operates at the standard 2,880 RPM on 50 Hz., it should sound a Bb minor chord (Bb,Db,F).

[Gents']

What part of it looks like the timer, Jason... and what exactly is that?

Thanks

[Robert Gift]

Robert, if the siren operates at the standard 2,880 RPM on 50 Hz., it should sound a Bb minor chord (Bb,Db,F).

OK. Thanks Daniel. Doesn't fit my 3450 rpm Ports & Pitches post.

[Daniel]

Given the necessarily tight tolerances between rotor and stator, what holds the outer stator section in place and maintains the tolerance? It appears that it could easily slip.

It is interesting that on each end, one row of ports is closed while the other is open. I suppose this increases the airflow out of each row?

[Robert Gift]

...It is interesting that on each end, one row of ports is closed while the other is open. I suppose this increases the airflow out of each row?

Sharp observation, Daniel!
Are they trying to not starve each stator row?

I thought the 5 holes in the outside rotor intake disk were to diminish it's output because the inner rotor intake was more restricted than if an open outside end.
But I now see both inside and outside rotors have the same 5-hole plate.
That blows my theory.

[Gents']

The rotors are held on the axle with tapered pins and the outer stator cover is held to the inner one, which is bolted directly to the motor, with the aid of the rolled metal strips you see down the middle of the rotors.

This is not the most friendly of sirens to take apart. I can see why not many were made, but I hope this to be the only operational one left in the country/world.

Still, quite new to this game, and no clue about the electrics, may I repeat my previous question: In siren terms, what is a timer for?

Thanks

[Robert Gift]

The rotors are held on the axle with tapered pins and the outer stator cover is held to the inner one, which is bolted directly to the motor, with the aid of the rolled metal strips you see down the middle of the rotors.

This is not the most friendly of sirens to take apart. I can see why not many were made, but I hope this to be the only operational one left in the country/world.

Still, quite new to this game, and no clue about the electrics, may I repeat my previous question: In siren terms, what is a timer for?

Thanks

Hi Gent.
I am new and unknowledgeable.
If I undertand your question, I presume the timer operates the siren in whatever mode is selected, for a preset time.
One presses the button, takes shelter, and the siren sounds for three to five minutes and automatically shuts off.
The timer powers the motor to create the different warnings. Alert/ Attack/All clear, etc.
Example: On for 7 seconds, off for 4, on for 7, ... for 5 minutes.
Or on steadily for 5 minutes. Or on and off more quickly for All Clear.

If you could follow the wires and draw up a circuit diagram, we could figure everything out.
I have been able to derive circuit designs by doing this. Can be fun detective work if no circuit schematic is available.

By those different parts, one attached to another, it may be difficult to keep rotors from touching stators with such tight tolerances.
When you remove anything, mark everything so you can reassemble exactly as was. Still, it may require fine adjustment.

[Gents']

Thanks again, Robert. I don't have the panel that has the buttons "Attack" and "Raiders Passed" for my siren. Just the testing controls. However, I still understand what you were saying about the signals and how the timer influences it. I have a feeling the siren was actually operated from another panel, remotely, and that the panel I have was just for testing. I may need to acquire some form of switching then.

With regards to the rotors and stators; when I dismantled it they were turning VERY well and the gap was precise. There was just a slight whirring noise as the flaking paint came across each port. If everything is assembled in the same way it was taken apart, I see no reason why it would not continue to be so precise.

As for following the wires... I'll have a go at that tomorrow.

[Daniel]

You might be able to test-run the siren with an electric drill, if you have one with sufficient speed and torque. You would need a socket or a close fitting, cup-shaped device to mate with the rotor hub.