The Woodward 505XT is Woodward’s top-tier 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 the most common control target for Drake Controls steam turbine retrofits, alongside the Peak 200. The 505XT handles mechanical drive and power generation service, with an integrated 8-inch color touchscreen serving as both 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.