The WOODWARD SPM-A 9907-028 is a high-precision analog synchronizer designed for the automatic synchronization of a generator to a bus. This specific model is a versatile speed and phase matching unit that provides the necessary bias signals to an electronic governor to bring an incoming generator into exact synchronism with the running bus before circuit breaker closure.

 

Product Overview

The SPM-A 9907-028 serves as a critical interface in power management systems. It automatically adjusts the speed of the prime mover so that the generator’s frequency and phase angle match the bus. Once the voltage, frequency, and phase are within the pre-set “window,” the unit issues a closure command to the generator circuit breaker. This prevents electrical and mechanical stress caused by out-of-phase paralleling.

 

Technical Datasheet & Parameters

 

Country of Origin

The WOODWARD SPM-A 9907-028 is designed and manufactured in the USA.

 

Application Fields

• Industrial Power Plants: Automatic paralleling of diesel or gas gensets.
• Marine Switchboards: Synchronizing shipboard auxiliary generators to the main bus.
• Co-generation: Interfacing steam turbines with utility grids.
• Emergency Standby: Rapid synchronization for data centers and healthcare facilities.
• Remote Microgrids: Managing multiple power sources in isolated mining or telecommunications sites.

 

Technical Description

Technically, the 9907-028 features a sophisticated phase-comparator circuit that monitors the zero-crossings of both the bus and generator potential transformer (PT) signals. It generates a corrective DC bias signal that is sent directly to the summing point of a Woodward speed control (such as the 2301A). The unit includes internal relays for “Breaker Closure” and “Sync Check” functions. Its analog design ensures a rapid, real-time response to frequency fluctuations, and it is housed in a rugged chassis designed to withstand the high-vibration environment of an engine control room.

Usage Instructions

1. Mounting: Install the synchronizer vertically in a control cabinet. Ensure it is protected from high-voltage EMI sources and excessive moisture.
2. Wiring: Connect the PT secondaries from both the generator and the bus to the designated terminals. Use shielded, twisted-pair wiring for the speed bias output to the governor.
3. Voltage Selection: Check the jumper or switch position to match your system voltage (115V or 230V) before applying power.
4. Adjustment: Use the “Dynamics” potentiometer to tune the speed of synchronization. Set the “Phase Window” to match the closing time of your specific circuit breaker to ensure a “top-of-the-clock” closure.
5. Functional Test: Use a synchroscope to verify that the SPM-A is correctly matching the phase before enabling the automatic breaker closure circuit.

For technical documentation and inventory status of the WOODWARD SPM-A 9907-028, please visit our industrial parts portal.