Functional Features:​ Continuously monitors prime mover speed via three separate speed-sensing units; each unit performs independent speed calculation; trip relays connected in a 2oo3 voting configuration ensuring that a single unit failure does not cause a spurious trip or prevent a genuine trip; front panel keypad and display for programming and status indication.

Application Scenarios:​ Overspeed protection for gas turbines, steam turbines, hydro turbines, compressors, and generators where precise speed monitoring and rapid trip action are required to prevent catastrophic overspeed damage.

Structural Characteristics:​ The system consists of three identical, independent speed-sensing units housed in a common enclosure. Each unit contains its own MPU input conditioning, processing, and trip relay.

Working Principle:​ Each of the three units continuously measures the frequency of its dedicated magnetic pickup. When a unit detects speed exceeding the trip setpoint, it activates its trip relay. The three relays are wired in a 2oo3 voting configuration, so that at least two units must vote “trip” before the final trip output is activated. This provides both fault tolerance and protection against single-point failures.

Installation Requirements:​ Install in a suitable control cabinet or enclosure. Use shielded wiring for MPU signals. Route field wiring with proper stress relief. Follow the plant wiring diagram provided in the manual for terminal block connections. Ensure proper grounding and isolation from electromagnetic interference sources.

Usage Notes:​ The overspeed shutdown device must be totally independent of the prime mover control system. The engine, turbine, or other prime mover must be equipped with this independent overspeed shutdown. Perform overspeed testing according to the documented procedure. Observe electrostatic discharge (ESD) precautions when handling the electronic modules.