If they actually did have some overheating issues I haven't seen it with mine. It wouldn't surprise me if there were cases of it though. These sirens are a almost 2 times the size of a Model 2 and obviously has a motor rated at half the HP. The rotor in them is 9 inches in diameter. It weighs about twice as much as the 2 as well. Federal Electric also apparently shipped them wired up in reverse. Reversing the direction of the rotor reduces the resistance and would take load off the the motor, so it wouldn't be out of the realm of possibility that reversing the direction of the rotor was used to mitigate an issue with overheating, even if it meant the SPL would take a hit. I've wanted to break mine down and rewire it to spin the correct way, but I avoided it out of paranoia that spinning it the correct way could potentially put too much strain on the motor.
Even with it spinning the wrong way it's still close to the output of a Model 2 and hits just over 100 dBc from 100 feet and 70 dBc from 1000 feet. Since the majority of the trees at and around the area of my mom's house were taken out by the tornado earlier in March it might be able to reach a further range now. I'm not going to try that for a while though, since people are still worked up over the situation. I could feel the tone it puts out in my chest whenever I stood within 20 feet of it while running. The motor's rated at 5000 RPM. At its fastest mine hit roughly 4600 RPM and ran at about 614 Hz after cleaning the old grease out of the bottom bearing. That particular run I used a short extension cord with solid copper wire cord connected to the siren itself to get as much voltage to it as I could. I ran it with extension cords at my grandparents house, so the voltage drop through the wire caused it to lose speed and drop to about the pitch of a typical Model 2 or other 10 port mechanical siren. The drop wasn't enough to set fire to anything or trip a breaker, so I left it that way.

https://www.youtube.com/watch?v=_lIQp-3fMoA
https://www.youtube.com/watch?v=pRfOxsBYGXY