ACA P-50/ ASC T-135

The ACA Penetrator-50 (P-50) / American Signal Corporation Tempest-135AC (T-135AC) is an extremely large, rotating electromechanical outdoor warning siren renowned as one of the loudest warning sirens ever manufactured. Key Specifications & Design • Sound Output: Rated at an incredible 135 decibels (dB) at 100 feet. • Motor: Powered by a massive 50-horsepower (HP) 3-phase motor. • Physical Size: The fiberglass rotating horn/projector is so large that an adult man can comfortably stand inside it without crouching. • Chopper Design: Features a dual-tone 8/12 port chopper configuration, giving it a distinctively deep, piercing, and eerie wail. • Rotation: Uses a chain-driven rotating mechanism to direct sound across a 360-degree area. History & Rebranding • Introduction: Originally introduced in 1980 by Alerting Communicators of America (ACA) as the Penetrator-50, and produced until 1991. • Acquisition & Renaming: Following corporate restructuring and bankruptcies, ACA reformed into [American Signal Corporation (ASC)](0.6.3, 0.6.8). The siren was rebranded over the years as the RM-135 and later reintroduced into the Tempest line as the Tempest-135AC (produced from roughly 2002 to 2007). • Operational Difference: Early ACA P-50 controllers stopped rotation immediately when power cut to the chopper, whereas later ASC T-135AC controllers allowed the heavy horn to coast and rotate after shutdown for a more effective attack signal pattern. • Discontinuation: Manufacturing of the massive AC unit officially ceased in late 2007, eventually succeeded by more modular battery-backed DC systems. Surviving models remain legendary among siren enthusiasts and are still tested or maintained in select U.S. counties (such as parts of Wisconsin, Tennessee, and Illinois).