Woodward 9907-175

The Woodward 9907-175 is a pulse-width-modulated (PWM) load sharing module specifically engineered for Caterpillar engines equipped with Caterpillar digital speed controls that accept a PWM input. As a member of Woodward’s Load Sharing Module family, the Woodward 9907-175 enables isochronous and droop load-sharing capabilities between Caterpillar-controlled generator sets and engines governed by Woodward electronic controls or other compatible load sharing modules. This cross-platform compatibility makes the Woodward 9907-175 a critical bridge component in mixed-fleet power generation systems where Caterpillar and Woodward equipment must operate in parallel.

Operating on an 18–32 Vdc power supply with approximately 5 W consumption, the Woodward 9907-175 senses generator real power output through three-phase PT and CT inputs, generating a PWM output signal proportional to the total real current. The module includes a load gain potentiometer for calibrating individual generator load signals, compensating for varying CT ratios or mismatched generator capacities. The Woodward 9907-175 carries EC compliance and UL/cUL listing, ensuring adherence to international safety and electromagnetic compatibility standards for industrial power generation applications.

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Description

Technical Specifications

Parameter Name	Parameter Value
Product Model	Woodward 9907-175
Manufacturer	Woodward
Product Type	Load Sharing Module (PWM/Caterpillar)
Power Supply	18–32 Vdc, approx. 5 W
PT Inputs	3-phase, 100–240 Vac line-to-line, 50–400 Hz
CT Inputs	3-phase, 3–7 Arms at full load
Load Sharing Input	0–3 Vdc into 25 kΩ (isochronous mode)
Output Type	PWM (pulse-width modulated) for Caterpillar speed control
Droop Range	No-load to full-load output reduction
Operating Temperature	-40°C to +70°C
Dimensions	273.6 × 214.1 × 59.2 mm
Weight	Approx. 1.36–1.4 kg
Approvals	EC Compliant, UL/cUL Listed

Main Features and Advantages

Cross-platform load sharing for mixed engine fleets: The Woodward 9907-175 is purpose-built to interface Caterpillar digital speed controls with Woodward power generation accessories, enabling load sharing between Caterpillar-equipped engines and those governed by Woodward electronic controls. This eliminates the need for proprietary Caterpillar load sharing hardware in facilities that operate mixed-brand generator sets, simplifying spare-parts logistics and reducing integration complexity.

PWM output matched to Caterpillar speed control inputs: Unlike analog-output load sharing modules that deliver a ±3 Vdc or 0.5–4.5 Vdc signal, the Woodward 9907-175 generates a pulse-width-modulated output specifically compatible with Caterpillar digital speed control systems. This direct compatibility ensures that Caterpillar engines receive the correct signal format without external signal conversion, preserving response speed and reliability in load-following operations.

Isochronous and droop operation flexibility: The Woodward 9907-175 supports both isochronous load sharing when operating in parallel with other generators, and droop mode for connection to an infinite bus or when paralleled with an isochronously controlled generator set. The external droop switch is wired in series with the auxiliary circuit breaker contact, and droop mode is selected when either contact opens, giving operators a simple, fail-safe method for mode transition.

Robust environmental construction: Tested for salt fog, 95% non-condensing humidity, and vibration up to 4 G, the Woodward 9907-175 is suitable for marine, offshore, and remote power generation environments. The wide -40°C to +70°C operating range and IP43-rated enclosure compatibility ensure reliable performance in harsh industrial conditions.