Description
Product Overview
The Woodward 9907-838 Load Sharing Module is used in generator control systems where engines equipped with compatible digital speed controls must share electrical load with other generator sets or Woodward-controlled units. It provides isochronous and droop load-sharing functions, helping coordinate generator output under different operating conditions. In a properly configured parallel-generation system, this function supports load distribution while the engine speed control manages the prime mover.
A key distinction is the PWM interface. The Woodward 9907-838 is intended for applications involving Caterpillar digital speed controls that accept a pulse-width-modulated input. Its 24 VDC supply and PWM output with surge protection distinguish it from the related 9907-175, which is listed without PWM output surge protection. Replacing one model with another should therefore be based on the existing wiring, control interface, and equipment documentation—not simply on the shared product family.
For maintenance teams, the Woodward 9907-838 can be relevant when restoring load-sharing functionality in an established generator installation or maintaining legacy power-generation equipment. Before installation, verify the complete part number, supply voltage, PWM input requirements of the connected speed control, current-transformer and potential-transformer wiring, synchronizer interfaces, and configured load-sharing mode. The module’s presence alone does not establish compatibility with every engine governor or generator controller. Confirm the control scheme against the applicable wiring diagram and installation manual before commissioning.
Product Introduction (Non-Templated)
Unequal kW sharing between parallel generator sets can point to a sensing, wiring, calibration, or control-interface problem—not necessarily a failed governor. The Woodward 9907-838 provides load-sharing functions for supported generator configurations and includes PWM output surge protection.
During replacement, match the original part number and confirm the receiving speed control accepts the module’s PWM signal. Verify field wiring and load-sharing settings before returning the generator to parallel operation.
Key Technical Specifications
| Parameter | Value |
|---|---|
| Product Model | 9907-838 |
| Manufacturer / Brand | Woodward |
| Product Type | Load Sharing Module |
| Series | LSM |
| Nominal Supply Voltage | 24 VDC |
| PWM Output | Yes |
| PWM Output Surge Protection | Yes |
| Load-Sharing Modes | Isochronous and droop |
| Intended Application | Generator sets with compatible digital engine speed controls |
| Associated Speed Control | Caterpillar digital speed control with PWM input, subject to system compatibility |
| Synchronizer Integration | Woodward SPM-A is identified as an example of associated equipment |
| Communication Protocol | Not specified as a network communication interface |
| Firmware Version | Not verified; confirm the unit’s identification and documentation |
| Operating Temperature | Verify against the applicable manufacturer specification and unit revision |
| Mounting / Dimensions | Confirm from the installation drawing for the supplied unit |
The model’s supply and PWM protection details are documented in Woodward’s product declaration and installation documentation. Do not substitute generic specifications from unrelated 9907-series controls.
9907-838
Related Products
These models and components serve related generator-control functions; they are not automatic drop-in replacements.
- 9907-175 — Related 24 VDC load sharing module with PWM output but without the listed PWM surge protection.
- SPM-A Synchronizer — Synchronizing accessory used in generator-paralleling systems.
- 2301A LSSC — Electronic load-sharing and speed-control family; verify the exact model and control architecture before considering substitution.
- Precision Frequency Control — Associated generator-control equipment for frequency adjustment.
- Automatic Generator Loading Control — Used in broader generator load-management arrangements.
- Import/Export Control — Supports power-flow control in suitable generator-to-grid configurations.
- Automatic Power Transfer and Loading Control — Related system-level control function for power transfer and loading sequences.
The listed associated equipment is described in Woodward’s load-sharing documentation. Confirm the actual system bill of materials before selecting related spares.
Frequently Asked Questions
1. What does the Woodward 9907-838 do?
It provides isochronous and droop load-sharing functions in compatible generator control systems. Its PWM output interfaces with supported digital engine speed controls.
2. Can I replace a 9907-175 with a 9907-838?
Not without checking the application. Both are 24 VDC load-sharing modules with PWM output, but the 9907-838 includes PWM output surge protection, which the 9907-175 does not list. Verify the existing wiring and system requirements before replacement.
3. Can I hot-swap this module?
Do not assume hot-swap capability. Follow the system shutdown, isolation, and replacement procedure in the applicable installation manual. The safe procedure depends on the generator-control arrangement and the consequences of losing load-sharing control during operation.
4. Does the Woodward 9907-838 support firmware v3.1?
A firmware version of v3.1 is not verified for this model from the available documentation. Confirm whether the referenced version applies to the module itself or to another connected controller. Check the unit’s nameplate and applicable technical documents.
5. Is this module compatible with every Caterpillar engine controller?
No. The documented application involves Caterpillar digital speed controls equipped with a compatible PWM input. Verify the exact speed-control model, signal requirements, and wiring before ordering.
6. How can I verify authenticity and condition?
Compare the nameplate, complete part number, revision markings, connector condition, and available inspection or test records. For used or refurbished units, request a clear statement of testing scope and any known faults. Packaging alone does not establish operational condition.
7. Does installing a replacement require reconfiguration?
Possibly. Load-sharing mode, droop settings, sensing connections, and speed-control input requirements must match the intended system configuration. Record existing settings before removal and validate load sharing under the site’s approved commissioning procedure.
Procurement note: For a replacement request, provide the full 9907-838 part number, nameplate details, existing speed-control model, and required condition. These details help reduce the risk of receiving a module that has the correct family designation but does not match the installed application.
