The Siren Board

Are rotors usually of aluminum and stators cast iron?

Thank you,

Don't know. I'd make them both the same, so expansion and contraction, things like that, would also be the same.

Most rotors today might be made of aluminum, as the sirens today have their rotors spin at a moderate speed. Rotors use to be mostly made of iron or steel, though sirens with high rotor-speeds could use a cast-iron rotor.

Thank you all.

I'd be afraid of cast iron flying apart from centrifugal force.
Cast iron may have internal defects and fissures and can become more brittle at low temperatures.

But I can see cast iron as a stator.

But good point about different expansion/contraction coefficients.

Thanks,

robert gift wrote:Thank you all.

I'd be afraid of cast iron flying apart from centrifugal force.
Cast iron may have internal defects and fissures and can become more brittle at low temperatures.

But I can see cast iron as a stator.

But good point about different expansion/contraction coefficients.

Thanks,

You wouldn't like old Model 5s/7s then.

Here is a vid of a 5 H.P. Federal with the old heavy rotors.. I know because I have have spun this rotor by hand many years ago when it was down for service... It takes about 5 mintues for this rotor to come to a complete stop. .. This siren was purchased around 1950 by the fire department. This is a great siren and still going strong today 56 years later!

http://www.longislandfirealarm.com/Will ... al%205.wmv

I heard a long while back that the smaller sirens had A "pig iron" mix of metal used for the rotors. Im talking about the A,D,and L Federal "street clearer" type of siren. There were other models too. I dont remember what the metal is made of.

Have they ever tried making parts out of carbon fiber?

That would be more expensive and brittle than metal.

I'll bet rotors and stators could be made out of composites, but only one issue...



What would be the point? Rotors and stators now work fine.