Product Overview
The Woodward 9907-175 is a load sharing module specifically engineered for use with Caterpillar engines equipped with Caterpillar digital speed controls that accept a pulse-width-modulated (PWM) input. As a critical component in generator set paralleling systems, the Woodward 9907-175 enables precise load sharing between engines controlled by Caterpillar digital speed controls and engines governed by Woodward electronic controls, bridging two distinct control ecosystems within a single power generation architecture. This module provides both isochronous and droop load-sharing capability, making it suitable for a wide range of generator set applications where multiple engines must operate in parallel while maintaining stable frequency and proportional load distribution.
The Woodward 9907-175 operates by sensing generator power output through three-phase potential transformer (PT) and current transformer (CT) inputs, calculating a load signal proportional to the actual real current delivered by each generator. This load signal is then shared across all paralleled generator sets via load sharing lines, allowing the module to compare individual generator load against the system average and generate appropriate correction signals. The Woodward 9907-175 converts this correction into a PWM output that interfaces directly with the Caterpillar digital speed control, adjusting engine speed and therefore generator load until all units share the total system load proportionally.
As part of Woodward’s Load Sharing Module family, the Woodward 9907-175 integrates seamlessly with other Woodward power generation accessories including the SPM-A Synchronizer, Paralleling Phase Switch, Automatic Generator Loading Control (AGLC), and Automatic Power Transfer and Loading Control (APTL). The module is housed in a compact chassis designed for panel mounting, with dimensions of approximately 274 mm × 214 mm × 59 mm and a weight of approximately 1.4 kg. Its robust construction and wide operating temperature range of -40°C to +70°C ensure reliable performance in demanding industrial and marine environments.
Technical Specifications
| Parameter Name | Parameter Value |
|---|---|
| Product Model | Woodward 9907-175 |
| Manufacturer | Woodward |
| Product Type | Load Sharing Module (PWM Output) |
| Power Supply | 18–32 VDC, approximately 5 W |
| Power Supply Protection | Undervoltage, overvoltage to +80 VDC, reverse voltage to –32 VDC |
| 3-Phase PT Inputs | 100–240 VAC line-to-line, 50–400 Hz |
| PT Input Burden | 1.6 W per phase at 240 VAC, 0.4 W per phase at 120 VAC |
| 3-Phase CT Inputs | 3–7 Arms at full load |
| CT Input Burden | 0.1 VA per phase at full load |
| Load Sharing Input | 0–3 VDC into 25 kΩ impedance (isochronous mode) |
| Sync Input | Compatible with Woodward SPM-A Synchronizer, 0.75% speed change per volt |
| Speed Trim | ±7.5% speed change with external 10 kΩ potentiometer |
| Output Type | PWM (Pulse-Width Modulated) |
| Load Signal Output | DC signal proportional to total real current, adjustable 0.86–2.0 VDC/Arms |
| Operating Temperature | -40°C to +70°C (-40°F to +158°F) |
| Dimensions (L×W×H) | 273.6 mm × 214.1 mm × 59.2 mm |
| Weight | Approximately 1397 g |
| Compliance | EC Compliant, UL/cUL Listed |
