WOODWARD 9905-973 Digital Regulator

WOODWARD 9905-973 (2301A Digital Load Distribution Governor)

1、 Model basic positioning
Product series: Woodward 2301A electronic speed controller, material number 9905-973, belonging to the 9905 low-voltage DC20-40V series, classic mechanical/electronic backup speed control unit
Core application: Diesel/gas generator sets, small industrial turbine speed regulation+multi unit load distribution, suitable for parallel operation of multiple units, can be used as backup redundant control for 505/505E digital speed controllers
Shutdown status (2026)
The 2301A series has officially ceased production and no longer accepts new original factory orders; The market source of goods only includes brand new, dismantled second-hand, and refurbished complete machines; Woodward provides long-term maintenance services, with the new generation of replacement models being the EGCP and 505XT series.
Differentiation Explanation
9905=2301A analog digital hybrid speed controller; Starting with 9907=505/505E fully digital turbine controller (you previously searched 9907-163), the functions of both are IO、 The software is not universal.
2、 Model segmentation meaning 9905-973
9905:2301A Low Voltage DC Power Supply Series (DC20~40V)
973: 0-20mA actuator output, standard load distribution, universal industrial non explosion proof basic model
Supporting driver: 0-20mA electro-hydraulic converter (such as CPC-II 9907-1200), fuel actuator
3、 Core control function
Speed closed-loop speed regulation
4-speed selectable speed measurement frequency range: 500~1500/1000~3000/2000~6000/4000~12000Hz, suitable for 500-12000RPM units; Steady state speed accuracy ± 0.1%, load response<100ms.
Supports dual modes of no difference (constant speed)/difference (droop), remote adjustable droop coefficient, and even distribution of multi machine parallel load.
Complete start stop logic
The cold and hot engine automatically starts the ramp, switches between idle/rated speed, avoids critical speed, and limits the deceleration ramp to prevent overspeed.
Redundant dual channel speed measurement input
Two MPU magnetic and electric probe inputs, automatic switching to backup channel for single speed measurement disconnection, zero speed detection, overspeed peak locking tripping.
Improve interlocking and alarm systems
10 external DI trip inputs, 10 external alarm DI; relay SPDT contact outputs alarm, overspeed, and operating status; RTC timestamp records trip/alarm events for easy accident tracing.
Remote given communication
RS485 Modbus RTU, 4-20mA analog remote speed/load setting, compatible with DCS and PLC remote control.
Fault safety design
Reverse acting actuator logic, controller loses power and automatically fully opens fuel, compatible with mechanical governor backup to avoid direct shutdown of the unit.
4、 Complete IO hardware resources
input
2-channel independent MPU magneto electric speed probe
8-way 4-20mA analog AI (with built-in circuit power supply, configurable for pressure, temperature, and power settings)
10 channels of 24VDC digital DI: start, stop, external interruption, grid connection permission, various fault switches
output
1-channel 0-20mA actuator drive output (controlling fuel valve/steam regulating valve)
6-way 4-20mA analog transmission output: upload speed, load, and valve position to the upper level
8-way SPDT relay contacts (5A/250VAC): overspeed trip, unit operation, fault alarm, grid connection status
communication
RS485 Modbus RTU， Support upper level monitoring and parameter reading and writing; The accompanying debugging software 2301 Tool is used for parameter tuning and waveform recording.
5、 Electrical and Environmental Parameters
table
Parameter specifications
Power supply DC 18~36V (rated 24VDC low voltage version)
Actuator output 0-20mA linear drive
Speed measurement input 0.5~12kHz, minimum 1Vrms starting voltage
Protection level IP54 panel protection, cabinet embedded installation
Certification CE, ATEX Zone 2, IACS UR E10 Merchant Shipping Certification
Working temperature -25 ℃~+60 ℃, no condensation
Dimensions 230 × 170 × 90mm, total weight 3.5kg
EMC standard EN 61000-6-2 Industrial anti-interference standard
6、 Quick differentiation of 2301A models in the same series
table
Applicable scenarios for part number power supply actuator current
9905-973 DC20-40V 0-20mA Standard Low Voltage Universal Model (this model)
9905-974 DC20-40V 0-400mA high-power actuator, large diesel unit
9907-030 AC88-132V High Voltage AC 0-20mA Factory 110VAC Power Supply Cabinet
7、 Typical application scenarios
Multiple diesel/gas generator sets are running in parallel in a self owned power plant, with load distribution control
Speed regulation of small waste heat power generation turbines and biogas engines
Oil and gas field stations, chemical pry mounted power units, as main regulators or 505E backup redundancy
Parallel control of ship generator sets and mobile power stations
8、 Complete set of supporting equipment
Execution mechanism: Woodward CPC-II 9907-1200 electro-hydraulic converter, fuel actuator
Speed measuring components: MPU passive magneto electric speed probe, shielded coaxial cable
Upper system: DCS, PLC, collects speed, load, and alarm signals through Modbus RTU
Debugging tool: 2301 Tool computer debugging software, parameter download, dynamic curve monitoring
9、 Key points of operation and maintenance replacement
Completely incompatible with the hardware and programs of 505 (9907-163) and cannot be directly replaced;
The two MPU speed measurement cables are individually shielded and layered with the power cable to avoid speed fluctuations;
The output circuit of the actuator is shielded from single ended grounding, reducing 4-20mA drive drift;
When multiple units are in parallel, the sag coefficient should be uniformly set to prevent load imbalance;
Priority should be given to refurbished complete machines for spare parts procurement, as new inventory is scarce and prices are high.