The Siren Board

Hello all, I have recently made my first major siren purchase and have couple questions. I bought a partially disassembled Federal Signal STH-10 with a 7.5 hp three phase motor for $120 dollars at a local auction. The motor was disassembled and upon further inspection it is obvious the windings are fried. My questions are 1. Is the motor proprietary or is it a standard frame size , and does anyone know what frame it is? ( I realize having it re-wound is an option). 2. I am in the process of trying to pull the rotor, am I correct in my understanding that I use the two threaded holes in the rotor with a puller to remove it? Also, I don't see any set screws, and noticed the motor shaft is internally threaded. Is there meant to be a bolt threaded into the shaft to retain the rotor? Thank you all , I have been reading on this site for awhile and I hope I can provide assistance to others in the future.

I have made progress! I got the rotor off with liberal use of PB blaster, a gear puller, hammering, and a propane torch. It was pretty stuck for how clean it looks. I am pretty sure the motor burned up because of the bearing. It sounds pretty horrid when you spin it by hand and I can see marks on the rotor, so there was enough play to allow the rotor to rub. So my question about the motor still stands.

I think rewinding and new bearings would be the way to go with the motor because then you don't have to match-up shaft length/size and fit to the siren stator etc.

Okay thanks , I'll see how much it costs, also might look at the local scrap yard and see what I can find.

Also, it looks like there would be a bolt in the end of the motor shaft to hold the siren rotor on. How would it be secured so it doesn't unscrew?

Is that a Marathon motor?

Not sure, all the tags say federal signal. Let me get some more detailed pictures of the motor in specific.

Why don't you have someone rewind the motor and put new bearings in it?

Motor pictures.

I will go with a rewind when I get the funds together, was just checking because I can find used three phase motors cheap. And a 7.5 hp face mount motor is relatively common.