WOODWARD 8440-2028

Description

Model Series

Technical Specifications

Functional Features

• Integrated governor and AVR in one unit — eliminates separate controller hardware, wiring, and synchronization complexity
• Isochronous and droop speed control with user-selectable droop percentage (1% to 10%) for single-unit or parallel operation
• 3-phase voltage sensing with phase-loss detection, phase-sequence verification, and phase-rotation indication
• Magnetic pickup (MPU) speed input compatible with most engine-mounted pickups (5–30 VAC, 100 Hz to 10 kHz)
• Color LCD display — shows real-time speed, voltage, frequency, load, fuel level, and alarm status; supports multiple languages
• Adjustable voltage setpoint via front-panel keypad, remote digital command, or PC software
• Comprehensive protection suite: over-speed, under-speed, over-voltage, under-voltage, over-frequency, under-frequency, over-current, reverse power, short circuit, ground fault, engine crank timeout, and emergency stop
• Governor fuel limit control with adjustable high-fuel-limit and low-fuel-limit settings
• Soft-start function for controlled engine startup and voltage buildup
• Load-share (droop) mode for stable parallel operation of multiple generators
• Remote sensing capability for compensating voltage drop across long cable runs
• RS-485 Modbus RTU communication for SCADA, BMS, and remote monitoring integration
• Two configurable analog outputs (4–20 mA or 0–10 VDC) for external monitoring of speed, voltage, load, or frequency
• Eight digital inputs for remote start/stop, emergency stop, mode selection, and alarm signals
• Four programmable relay outputs for alarm, pre-alarm, run status, and fault indication
• Event logging stores the last 200 alarm events with timestamps (expandable to 1,000 with SD card option) for root-cause analysis
• Adjustable governor gain, speed loop bandwidth, and voltage loop bandwidth for optimization to specific engine/generator combinations
• Engine cranking output — provides a timed cranking signal to the engine starter during startup sequence
• Pre-lubrication timer — delay between start command and fuel admission for engine oil pressure buildup
• Emergency stop (E-stop) input — hardwired input that immediately shuts down fuel and excitation within 10 ms
• Adjustable acceleration/deceleration ramp rates for smooth speed transitions
• Built-in data logger — records operating parameters at configurable intervals for preventive maintenance
• Password-protected configuration — prevents unauthorized parameter changes

Performance Parameters

Material Composition

Structural Features

• Compact DIN-rail mountable module designed for installation inside generator control panels or switchgear cabinets
• Front panel with color LCD display (128 × 64 pixels) — shows real-time speed, voltage, frequency, load percentage, fuel level, and alarm status
• Front-panel silicone keypad — 4 × 4 button matrix for navigating menus, adjusting setpoints, and viewing alarms; all buttons are sealed behind the IP65 membrane
• LED indicators on front panel: Power (green), Run (green), Fault (red), Alarm (yellow), Emergency Stop (red flashing)
• Rear terminal block array with clearly labeled connections for:
  • Speed input (MPU+ / MPU−)
  • Voltage sensing (L1, L2, L3, N)
  • Exciter field output (F+, F−)
  • Governor actuator output (0–10 VDC or 4–20 mA)
  • Remote sense (RS+, RS−)
  • Analog outputs (AO1, AO2)
  • Digital inputs (DI1–DI8, common)
  • Relay outputs (RO1–RO4, NO/NC/common)
  • RS-485 communication (A, B, GND)
  • Emergency stop (E-stop, NO/NC)
  • Crank output (CRANK+, CRANK−)
  • Auxiliary power (if external supply used)
  • SD card slot (on 8440-2058 variant)
  • USB port (on 8440-2058 variant)
• Adjustable gain and stability trimmers accessible via front panel (under hinged cover)
• Ventilation slots on top and bottom for natural convection cooling (no internal fan)
• EMC shielding via metal enclosure interior coating and filtered I/O connections
• Hinged front cover with tamper-resistant screws — protects terminals and keypad from dust and accidental contact
• Label area — laser-etched identification on the enclosure face (model number, ratings, certifications); etching is permanent and resistant to chemicals and abrasion
• DIN rail clip — spring-loaded 35 mm DIN rail mounting clip with captive screws

Working Principle

1. The controller draws self-power from the generator terminals — no external power supply is required during normal operation
2. Speed Control Loop (Governor):
   • The magnetic pickup (MPU) mounted on the engine flywheel generates an AC voltage proportional to engine speed
   • The controller converts the MPU signal to a digital speed value via an internal frequency-to-voltage converter
   • The microprocessor compares the actual speed to the user-defined setpoint
   • The error signal is processed by a digital PID control algorithm with adjustable gain and bandwidth
   • The PID output drives the governor actuator output (0–10 VDC or 4–20 mA), which controls the fuel valve actuator on the engine
   • The fuel valve adjusts fuel flow to maintain the set speed regardless of load changes
3. Voltage Control Loop (AVR):
   • The 3-phase voltage sensing circuit continuously measures the generator terminal voltage (L1, L2, L3)
   • The microprocessor computes the RMS voltage and compares it to the user-defined voltage setpoint
   • The error signal is processed by a digital PID control algorithm
   • The PID output drives a PWM exciter field driver, which controls the DC current supplied to the brushless exciter field winding
   • The exciter field current adjusts the exciter stator output, which controls the main generator field current via the rotating rectifier assembly
   • This closed-loop system maintains constant terminal voltage under all load conditions
4. Protection Logic:
   • The microprocessor continuously monitors speed, voltage, frequency, current, and I/O states
   • If any parameter exceeds a configurable threshold (over-speed, under-speed, over-voltage, under-voltage, phase loss, reverse power, ground fault), the controller immediately reduces or cuts excitation and/or fuel
   • The emergency stop input takes immediate priority over all other functions, shutting down fuel and excitation within 10 ms
5. Parallel Operation (Droop Mode):
   • When multiple generators operate in parallel, each unit is set to the same droop percentage (typically 4% or 5%)
   • The droop characteristic causes each generator to share load proportionally to its capacity without a central load-sharing controller
   • The RS-485 Modbus RTU interface enables remote monitoring and control of each unit from a central SCADA or BMS
6. Data Logging:
   • The controller records operating parameters (speed, voltage, frequency, load, alarms) at configurable intervals (1 second to 1 hour)
   • Event logs store the last 200 alarm events with timestamps for root-cause analysis
   • Data is accessible via the LCD display, RS-485 Modbus RTU, or SD card (on 8440-2058 variant)

Advantages and Highlights

• Single-unit GAVR + protection integration — replaces governor, AVR, and protection relay in one compact unit, reducing cost, wiring, and panel space by up to 50%
• Digital precision — ±0.1% speed regulation and ±1% voltage regulation, superior to analog controllers (typically ±0.5% speed, ±3% voltage)
• Zero drift over time — microprocessor-based control eliminates component aging drift inherent in analog designs
• Self-powered operation — derives all operating power from generator terminals; no external power supply needed
• Wide engine compatibility — supports gas turbines, diesel engines, and dual-fuel engines from 30 kW to 5,000 kW
• Fast transient response — <100 ms speed recovery and <50 ms voltage recovery on 100% load steps
• Built-in Modbus RTU communication — seamless integration with SCADA, BMS, and remote monitoring systems
• Color LCD display — real-time visualization of all operating parameters without a laptop
• Configurable protection suite — adjustable over/under-speed, over/under-voltage, over/under-frequency, reverse power, ground fault, and emergency stop
• Parallel operation ready — droop control enables stable load sharing without external load-sharing controllers
• Event logging (200 events) — stores alarm history with timestamps for preventive maintenance
• Password-protected configuration — prevents unauthorized parameter changes
• Front-panel commissioning — all setpoints and gains adjustable via keypad without a laptop
• PC-based configuration — Woodward TOOLBOX software enables full parameter tuning, data logging, and firmware updates via RS-485 or USB
• Long service life — MTBF >150,000 hours, no moving parts, no wear-out components
• Robust environmental rating — operates from -20°C to +70°C, suitable for harsh industrial environments
• Compact form factor — fits in tight spaces on DIN rails and in control cabinets

Applicable Industries

Installation Requirements

Usage Precautions

• Never connect the controller to a live generator without verifying all wiring against the wiring diagram — incorrect connections will destroy the controller and damage the generator
• Verify phase sequence before energizing the generator — reverse phase sequence will cause the governor to malfunction and may damage the engine fuel system
• Verify MPU polarity and signal level before startup — incorrect MPU wiring causes erratic speed control and overspeed conditions
• Do not exceed the rated exciter output current of 10 A DC — overloading will destroy the PWM output driver
• Do not bypass the built-in surge protection devices — external transients from lightning or switching will damage internal circuitry
• Allow 30 seconds warm-up time after initial power-on before expecting accurate speed or voltage regulation
• Do not adjust internal gain trimmers unless qualified — incorrect settings cause governor oscillation (hunting) or AVR instability
• Use shielded cable for all analog and digital I/O in electrically noisy environments (near VFDs, welders, or large motors) to prevent false readings
• Ensure proper ventilation — do not install in a sealed enclosure without airflow; overheating above 70°C causes thermal shutdown
• Perform annual inspection of all terminal connections for tightness, corrosion, and wire insulation integrity
• Do not operate the controller with the front cover removed — exposed terminals carry up to 300 VDC and 10 A
• When replacing the unit, match the model number exactly — 8440-2028 is not interchangeable with 8440-1028 without reconfiguration
• Log all fault events using the built-in event log or external SCADA for preventive maintenance
• Do not use the controller with generators exceeding 600 VAC line-to-line — this will destroy the voltage sensing input circuit
• For parallel operation, configure identical droop settings on all units — mismatched droop causes circulating currents, instability, and equipment damage
• Test the emergency stop input monthly — verify that E-stop shuts down fuel and excitation within 10 ms
• Do not connect the governor actuator output to a non-compatible fuel valve — verify actuator type (0–10 VDC or 4–20 mA) matches the valve specification
• Store spare units in a dry, temperature-controlled environment (0°C to 40°C, <70% RH) with anti-static packaging
• Update firmware via Woodward TOOLBOX software to the latest version for improved algorithms and bug fixes
• Do not modify the internal firmware — only Woodward-authorized personnel should perform firmware updates
• Protect the LCD display from direct sunlight — prolonged UV exposure degrades the display contrast over time
• Use the correct system voltage variant — 8440-2028 is for 24 VDC systems only; do not connect to 12 VDC or 120 VAC systems

Software and Configuration Tools

Key Parameters Summary (Bold Reference)