WOODWARD 8440-1706 A SPM-D11 High-precision digital synchronizer

The Woodward 8440-1706 (SPM-D11) is a high-precision digital synchronizer designed for three-phase AC generators.

Part of the well-known SPM-D series, this "Synchronizer and Power Manager" is specifically engineered to automate the process of bringing a generator online by matching its frequency, voltage, and phase angle to a busbar or another power source.1

Technical Parameter Table

Related Models

The SPM-D11 is often paired with or replaced by these related components:

8440-1705 (SPM-D10): A similar synchronizer but typically used for single-phase sensing or simplified applications.

easYgen-3000 Series: More advanced power management controllers that incorporate the synchronizing functions of the SPM-D11.2

8440-1002 (SPM-D10/YB): A variant with specialized voltage/frequency bias characteristics.

LS-5 Series: Circuit breaker controllers often used in conjunction with synchronizers for complex busbar management.

Application Cases

Standby Generator Sets: Automatically synchronizing a backup generator to a building’s busbar during a power transition.

Co-generation Plants: Ensuring a seamless connection between onsite turbine generators and the public utility grid.

Marine Power Systems: Synchronizing multiple shipboard diesel generators to share the electrical load without interruption.

Mobile Power Modules: Used in rental power units where fast, reliable synchronization is required for varying grid conditions.

Product Advantages and Features

Full Three-Phase Sensing: Unlike single-phase units, the SPM-D11 monitors all three phases of both the generator and the bus, providing superior safety and accuracy.

Integrated Check-Sync: Includes an internal "Slip Window" and "Dwell Time" logic to ensure the breaker only closes when the electrical conditions are perfect, preventing mechanical damage to the generator.

Analog & Discrete Bias: Capable of sending ±10V or 4-20mA signals to speed governors and voltage regulators (AVRs) to force the generator into alignment.3

Microprocessor Precision: Digitally calculates the exact moment to send the "Close" signal to the breaker, accounting for the inherent mechanical delay of the circuit breaker itself.

User-Friendly HMI: The front-facing LCD and push-buttons allow for easy commissioning without the absolute need for a laptop in the field.

Other Models in the Same Series

The SPM-D (Synchronizer Power Manager - Digital) family includes:

SPM-D10: Standard synchronizer (basic version).4

SPM-D11/LSX: Synchronizer with added load-sharing and export control capabilities.5

SPM-D21: A more advanced version designed for two-breaker control (e.g., generator breaker and tie breaker).6

8440-1431: A specific variant of the SPM-D11 series with custom firmware for specialized utility requirements.

Introduction

The Woodward 8440-1706 (SPM-D11) is a robust, microprocessor-based synchronizer that eliminates the human error associated with manual generator paralleling.

7 By continuously monitoring the voltage and frequency of both the generator and the utility bus, it issues corrective commands to the engine's governor and voltage regulator.

Once the generator is perfectly "in phase," the SPM-D11 triggers the circuit breaker, ensuring a smooth transition of power.

It is highly valued for its reliability in critical infrastructure where even a minor synchronization error could result in significant equipment damage.