The Woodward 505XT is a digital governor and safety system for single-valve and single extraction/admission industrial steam turbines of all sizes. It replaces the legacy 505 series and is a common Drake Controls retrofit platform alongside Peak 200. The 505XT handles mechanical-drive and power-generation service, with an integrated 8-inch color touchscreen serving as both the operator panel and programming station.
Key Features
Control
- Five PID controllers: Speed, Extraction/Admission, Cascade, Aux-1, Aux-2
- PID-to-PID logic for stable bumpless mode transfers during plant upsets
- Automatic ratio-limiter for extraction/admission decoupling
- Manual, semi-auto, automatic, and remote start sequences
- Steam map entry (3-point) for automatic calculation of all PID-to-valve ratios
- Dual speed probe inputs (passive or active MPUs)
- One or two split-range actuator outputs
Protection
- 3 critical speed avoidance bands
- Overspeed anticipation and shutdown protection
- Configurable under- or over-pressure shutdown logic
- Minimum and maximum speed and load settings
- Maximum low-pressure stage overpressure limits
- Minimum high-pressure stage flow limits
I/O and Communications
- Ethernet: Modbus TCP and OPC; SNTP clock sync to plant DCS
- Serial: Modbus RS-232/RS-485
- CAN ports for LINKnet HT distributed I/O expansion
- Optional LINKnet HT modules: 16 analog in, 4 analog out, 8 RTD, 16 DI, 16 relay out
- Unpluggable terminal blocks for installation and hot-swap replacement
Applications
- Single-valve and extraction/admission industrial steam turbines
- Turbo-expanders driving compressors, pumps, or industrial fans
- Generator drive (mechanical drive and power generation service)
- Steam plant parameter control: speed, load, header pressure, tie-line power
- Retrofit replacement for legacy Woodward 505 series controls
Drake Controls Services
Drake Controls is a Woodward Authorized Distributor and Recognized Turbine Retrofitter. We stock 505XT units, parts, and LINKnet HT I/O modules for rapid delivery. Our field service team handles retrofit engineering, panel design, installation, and commissioning. The 505XT is a primary retrofit target on Drake steam turbine projects alongside the Peak 200 for sites requiring the full extraction/admission feature set or higher I/O count.