Hello,
I have an early version of the Federal-5 siren. It's called the model AV37X. I think it was made in 1937. It has a three phase 7.5/hp motor which is housed in a cast iron frame with a large circular base ring. It's identical to the pictures of the Federal siren which was posted here by 'Siren_Dude' in the following URL.
https://airraidsirens.com/forums/viewtopic.php?t=10607
My siren is in better condition. The motor still runs. I think it was rebuilt (rewound) about twenty years ago. It has new bearings too.
The rotor seems to be cast aluminum. I think it may also have some magnesium in the alloy. A few of the blades which cover the holes in the stator frame have some damage. One blade has a semicircular chip on the edge which is about 10-mm in diameter. Another blade has a crack about one centimeter long through the aluminum material. A third blade has a dent on the edge which about 25-mm long and a few millimeters deep. The siren may have been mishandled when it was removed from service but it's also possible that it operated with the rotor damage for many years.
The rotor seems to be similar if not identical to later ones which were used on Model-5 sirens which do not have the cast iron motor frame with the circular base. My rotor measures 18" in diameter and 5-9/16" high. The center hole fits the 1.125" (1-1/8) motor shaft and is held in place with a gib key. The shaft is not drilled or tapped for a bolt to hold down the rotor.
I have attached a picture (below) of a rotor which seems to be identical to mine. It was posted here by group member idk6000 in 2011. It came from a real Model-5, not the AV37X.
My question for the group is what are the chances of finding another rotor like mine? I'm hesitant about using the rotor that came with the siren because of its age and the damage I described. Does anyone know what range of years Federal used this rotor for the Model-5?
On another topic, has anyone attempted to fabricate a large rotor like the Model-5 from aluminum material? I have some ideas for how it could be done, but I'll save that for another post.
Thanks for your replies