Federal Signal 3T22 Siren Test - Olds, IA 

Plus this is a 3 phase model that uses an induction motor unlike both of Clyde single phase models that use repulsion motors. The speed of these induction motors are dependent on the line frequency. (60 hz here in the US) So even if both Intakes were blocked on this one, It would stay at the same overall speed. Repulsion motors like Clyde Ohio's 3t22's are not based on the line frequency unlike induction motors but rather the placement of the brushes. Even a standard load for these kind of motors will significantly drop the speed. So the motors in single phase FS sirens like these are designed to run at 3450 RPM with load from the choppers. But since both dampers on Clyde Ohio's high pitched siren close when running, there's little to no load on the motor so it spins much much faster than it's meant to spin at. Hope that explains the differences between Xt22A's and B's as well as why one Clyde Ohio 3T22 is insanely high pitched while the other is at the pitch of a Carter air raid siren.

@@zachzebra56Oh okay