WOODWARD 9905-021 – Load Sharing Speed Control | Governor & Control Platform
Engineering Background
The WOODWARD 9905-021 is a precision Load Sharing Speed Control module engineered for parallel generator set applications where isochronous load sharing and tight frequency regulation are mission-critical. Developed within WOODWARD’s proven governor and control architecture, this unit has been deployed across power generation, marine propulsion, and industrial prime mover installations worldwide. Its analog-digital hybrid design delivers deterministic response characteristics that digital-only controllers cannot replicate in legacy plant environments.
Product Positioning
Designed for procurement engineers and plant integrators who require a drop-in replacement or OEM-equivalent control module for WOODWARD-governed generator sets. The 9905-021 is the authoritative choice when system uptime, load balance accuracy, and compatibility with existing WOODWARD actuator wiring are non-negotiable. Konmask.com supplies this module with full traceability documentation, supporting both MRO (Maintenance, Repair & Overhaul) and capital project procurement workflows.
Complete Technical Specifications
| Part Number | 9905-021 |
| Manufacturer | WOODWARD |
| Function | Load Sharing Speed Control |
| Control Mode | Isochronous Load Sharing / Droop (selectable) |
| Input Power | 18–40 VDC (nominal 24 VDC) |
| Speed Signal Input | Magnetic pickup (MPU), 100–10,000 Hz |
| Load Sharing Signal | 0–5 VDC differential bus |
| Actuator Output | 0–200 mA (proportional current output) |
| Speed Droop Range | 0–10% adjustable |
| Frequency Regulation | ±0.25% steady-state (isochronous mode) |
| Operating Temperature | -40°C to +85°C |
| Enclosure / Form Factor | DIN-rail or panel-mount module |
| Weight | 1,750 g (approx.) |
| Certifications | CE, UL (refer to OEM datasheet for current listing) |
| Compatibility | WOODWARD EG, UG, and ProAct actuator families |
Note: Specifications are based on WOODWARD published data. Confirm with OEM datasheet for your specific revision level.
Proven Application Environments
- Parallel Generator Sets — Isochronous load sharing across 2–8 genset bus configurations in standby and prime power plants.
- Marine Power Systems — Shipboard generator paralleling where frequency stability is required under variable hotel and propulsion loads.
- Industrial Prime Movers — Gas turbine and diesel engine governor control in oil & gas, petrochemical, and mining facilities.
- Data Center & Critical Infrastructure — N+1 and 2N generator redundancy schemes requiring precise kW load distribution.
- Utility & Cogeneration Plants — Grid-parallel and island-mode operation with automatic mode transition.
Engineering Advantages
- Isochronous Load Sharing Bus — Proprietary WOODWARD load sharing line ensures equal kW distribution without frequency droop penalty.
- Wide MPU Input Range — Accepts magnetic pickup signals from 100 Hz to 10 kHz, compatible with virtually all flywheel tooth configurations.
- Adjustable Gain & Stability — On-board potentiometers for gain, stability, and droop allow field tuning without software tools.
- Robust EMI Immunity — Designed for industrial electrical environments with high-voltage switching transients and RF interference.
- Direct Actuator Drive — Current-output stage directly drives WOODWARD EG and ProAct series actuators without external amplifiers.
- Proven Longevity — Field-proven design with decades of installed base; spare parts and technical support ecosystem fully established.
System Architecture & Signal Flow
The 9905-021 operates within a closed-loop governor architecture:
- Speed Sensing — MPU signal from engine flywheel is conditioned and converted to a frequency-proportional DC voltage.
- Speed Reference Comparison — Sensed speed is compared against the internal speed reference setpoint; error signal is generated.
- Load Sharing Arbitration — The load sharing bus voltage (shared across all paralleled units) modifies each unit’s speed reference to equalize kW output.
- PID Control Loop — Proportional-Integral-Derivative algorithm processes the combined error signal with field-adjustable gain and stability parameters.
- Actuator Drive Output — Corrected control signal is converted to a 0–200 mA current output driving the fuel actuator to correct engine speed and load.
Sourcing & Quality Verification
- Genuine OEM Parts — Konmask.com sources WOODWARD 9905-021 modules through authorized distribution and verified industrial surplus channels.
- Inspection Protocol — Each unit undergoes visual inspection, label verification, and functional pre-check prior to dispatch.
- Traceability Documentation — Certificate of conformance, packing list, and available test records supplied upon request.
- Counterfeit Risk Mitigation — All units verified against WOODWARD part marking standards; suspect units are quarantined and not listed.
- Warranty — 90-day operational warranty against defects in materials and workmanship; extended warranty available on request.
Procurement Process
- Submit RFQ — Contact [email protected] or call +0086 19859288691 with your required quantity and delivery timeline.
- Quotation & Lead Time — Receive a formal quotation within 1 business day including unit price, shipping options, and estimated lead time.
- Order Confirmation — Purchase order or online checkout accepted; proforma invoice issued for wire transfer payments.
- Inspection & Dispatch — Unit inspected, packed to IEC 60068 transport standards, and dispatched with full documentation package.
- Delivery & Support — DHL / FedEx / SF Express tracked shipping; post-delivery technical support available via email.
Technical FAQ
Q: Is the 9905-021 compatible with WOODWARD UG governors?
A: Yes. The 9905-021 is designed to interface with WOODWARD UG-series actuators via the standard current output. Verify actuator coil resistance matches the output current range.
Q: Can this unit operate in droop mode only (no load sharing bus)?
A: Yes. The load sharing bus connection is optional. With the bus disconnected, the unit operates in conventional droop speed control mode with adjustable droop percentage.
Q: What is the maximum number of units that can share a load sharing bus?
A: WOODWARD specifies up to 8 units on a single load sharing bus. Bus termination resistors must be installed at each end of the bus cable per WOODWARD wiring guidelines.
Q: Do you supply the OEM datasheet and wiring diagram?
A: Yes. WOODWARD technical documentation is provided with every order. Additional application notes are available upon request.
Q: What is the lead time for the 9905-021?
A: Standard lead time is 3–7 business days for in-stock units. Contact us for urgent requirements — expedited dispatch is available.
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Contact: [email protected] | +0086 19859288691
