The Siren Board

The Federal Sign And Signal 500 Models consisted of a rotation method that was proven faulty. It was a similar problem to the Allertor’s chain-drive snapping, but the 500 has a lighter rotator. The 500 Models have a reputation of belts slipping or snapping, and losing tension, so it is not surprising that this particular model is having faults.

The whole system hasn’t been run for ages, unless you count the Model 7T used on Catalina island as a fire siren or a moon whistle siren.

Now that I think about it, the 500 SH-TT seems like a budget of an Allertor.

The 500-SHTT came out about 15-ish years before the first Allertors were produced. They have no relation whatsoever, beyond the rotator being driven by the chopper motor.

And despite what the ARS wiki claims, chains snapping on Allertors are very uncommon, and chains are better than belts for durability as they don't stretch and lose their strength over time the way belts do.

+1 karma for you
I saw you had a negative karma, so I just wanted to help out a bit