Woodward 9907-173 Retrofit-Ready Load Sharing Module for Governor Control Systems
The Woodward 9907-173 is a proven Load Sharing Module engineered for isochronous parallel operation of generator sets within the Woodward Governor Control Series. As legacy power generation and industrial control systems reach end-of-life or face discontinued spare parts availability, the 9907-173 remains one of the most sought-after retrofit and replacement components for facilities seeking to extend the operational life of their existing control infrastructure without a full system overhaul.
This module enables precise real load sharing between paralleled generator sets, maintaining frequency stability and balanced kW distribution across the bus. It is fully compatible with Woodward EG-3P actuators, 2301A Load Sharing and Speed Controls, and 723 Digital Speed Controls — all of which are commonly found in aging power plant control cabinets, marine propulsion panels, and industrial co-generation systems. When replacing a failed or obsolete 9907-173, engineers must verify the existing terminal wiring against the original schematic, confirm the droop/isochronous switch setting, and validate the load sensor input signal range before energizing the replacement unit.
Upgrade Compatibility Table
| Parameter | Details |
|---|---|
| Compatible Series | Woodward Governor Control Series, 2301A, 723 Digital |
| Installation Type | Panel-mount, DIN-rail adaptable with bracket |
| Communication Compatibility | Analog signal (4–20 mA load sensor input); no fieldbus required |
| Replacement Recommendation | Direct drop-in for 9907-173; verify terminal block pitch and wiring polarity |
| Commissioning Focus | Droop %, load gain pot, cross-current compensation wiring |
| Warranty | 12-Month Warranty — all units tested prior to shipment |
Retrofit Planning for Existing Automation Systems
Successful retrofit of the 9907-173 into an existing control cabinet requires a structured approach. Begin by auditing the power supply rail — the module requires a stable 24 VDC supply, and aging Woodward PS-24 power supply modules should be tested for output ripple before the new unit is installed. If the cabinet also houses a 2301A Load Sharing and Speed Control, confirm that the load sharing lines (terminals L+ and L−) are correctly cross-connected between all paralleled units.
For systems using the Woodward 723 Digital Speed Control as the primary governor, the 9907-173 interfaces via the analog load signal output. Technicians should verify that the 723’s load sensor calibration has not drifted, as an uncalibrated load signal will cause the replacement 9907-173 to hunt or fail to share load correctly. In cabinets where a Woodward 2301D or 2301E has been installed as an interim upgrade alongside legacy 9907-series modules, confirm that the load sharing bus voltage levels are compatible — mixed-generation modules can produce offset errors if gain settings are not matched.
Backplane and rack considerations are equally important. The 9907-173 is typically mounted in a dedicated panel position; if the original mounting hardware has corroded or the terminal block has been damaged, replacement Woodward terminal strip assemblies should be sourced concurrently. For systems that also include a Woodward 9905-466 or 9905-571 actuator driver card in the same cabinet, ensure that the actuator output wiring is isolated from the load sharing signal lines to prevent cross-talk interference.
Where the control system also manages communication to a SCADA or DCS layer via a Woodward NetCon 5000 or similar serial gateway, the retrofit window should include a verification step to confirm that the load sharing status signals are correctly mapped in the HMI display. Operators should not rely on HMI load bar readings until the new module has been bench-tested and field-calibrated. All pre-shipment units from our inventory undergo functional load sharing simulation testing before dispatch.
Downtime Control During System Migration
Minimizing downtime during a 9907-173 replacement requires pre-staging the replacement module with all pot settings documented from the outgoing unit. Photograph or record the positions of the droop adjustment, load gain, and cross-current compensation potentiometers before removal. If the generator set must remain online during preparation, coordinate with the site electrical team to transfer load to a standby unit or utility tie before isolating the control cabinet.
Original PLC or governor program logic stored in a Woodward 723 or 2301A is not affected by replacing the 9907-173, as this module operates in the analog signal domain and does not store program data. However, if the site has migrated to a Woodward MicroNet or Proact III digital governor platform, confirm that the load sharing architecture has been updated to use the digital load sharing protocol rather than the legacy analog cross-current method — mixing protocols will result in instability at synchronization.
Post-installation, perform a no-load governor response test before paralleling. Gradually transfer load and observe the kW split between units. Fine-tune the load gain potentiometer in small increments until load sharing error is within ±2% of rated kW. Document all final pot positions and update the site maintenance record. Our team provides pre-shipment test reports for all 9907-173 units upon request.
Retrofit Support FAQ
Q: Is the 9907-173 a direct replacement for all Governor Control Series load sharing modules?
A: The 9907-173 is the standard Load Sharing Module for the Woodward Governor Control Series. It is a direct replacement for units of the same part number. For adjacent models such as the 9907-172 or 9907-174, terminal wiring and gain settings may differ — always cross-reference the original wiring diagram before installation.
Q: What pre-shipment testing is performed on each unit?
A: Every 9907-173 in our inventory is functionally tested for load sharing signal output, power supply input range, and potentiometer response before dispatch. A test report is available upon request. All units carry a 12-month warranty from date of shipment.
Q: Can this module be used with a Woodward 723 Digital Speed Control?
A: Yes. The 9907-173 interfaces with the 723 via the analog load sensor signal. Ensure the 723’s load sensor calibration is current and that the load sharing terminal connections match the 723 wiring diagram for parallel operation.
Q: How do I verify wiring compatibility before installation?
A: Compare the terminal block layout of the replacement 9907-173 against your existing wiring schematic. Key terminals to verify include the load sensor input (L+/L−), power supply (B+/B−), and cross-current compensation lines. If the original schematic is unavailable, our technical team can assist with identification based on the cabinet model and generator set nameplate data.
© 2026 SMARTNEXMSK. All rights reserved.
Original Source: https://smartnexmsk.com
Contact: sales@smartnexmsk.com | +86 18259474341
