The WOODWARD 9907-028 is a high-performance Speed and Phase Matching (SPM-A) synchronizer designed to automatically align the frequency and phase of an incoming generator bus with a main utility bus. This Rev F edition provides sophisticated bias signals to the prime mover’s speed control, ensuring rapid, bumpless synchronization for power generation systems.
Product Specifications
- Model Number: 9907-028
- Revision: F
- Input Voltage: 115/230 Vac (Selectable), 50/60 Hz
- Power Consumption: 5 W maximum
- Phase Offset Range: Adjustable from -10° to +10°
- Stability: ±0.25% over the full temperature range
- Operating Temperature: -40°C to +70°C (-40°F to +158°F)
- Output Signal: Analog bias signal (compatible with Woodward 2301, 721, and 827 series)
- Control Type: Frequency and phase-lock synchronization
- Enclosure Rating: NEMA 1 equivalent (back-panel mount)
The Woodward 9907-028 Rev F serves as a critical interface for automated power management, delivering precise frequency matching and phase alignment to prevent mechanical stress during breaker closure. Its rugged construction and Revision F enhancements offer superior noise immunity and signal stability compared to earlier legacy units, making it an essential component for reliable grid-paralleling operations in industrial environments.
WOODWARD SPM-A SYNCHRONIZER MODULE 9907-028
Model Comparison: 9907-028 vs. Similar Variants
The 9907-028 is often compared to the 9907-029 or 9905 series. The primary distinction lies in its voltage sensing capabilities and output compatibility. While the 9905 series often utilizes pulse-width modulation (PWM) or discrete step outputs, the 9907-028 provides a continuous analog bias signal, specifically optimized for Woodward’s analog load sharing and speed control systems. Additionally, Rev F features updated internal circuitry that handles harmonic distortion on the bus more effectively than the older Rev A or B versions.
Operation Tips
- Phase Window Adjustment: Always ensure the “Phase Window” potentiometer is set according to your circuit breaker’s closing time; setting it too narrow may prevent synchronization if the breaker is slow.
- Check Phase Rotation: Before commissioning, verify that both the generator and the bus have identical phase rotation (L1-L2-L3); the SPM-A cannot correct for reversed phases.
- Voltage Balancing: Ensure the generator voltage is matched to the bus voltage within 5% before enabling the synchronizer to avoid large reactive power surges upon closure.
- LED Monitoring: Utilize the “Enable” and “In-Sync” LEDs on the faceplate for real-time troubleshooting; if the “In-Sync” light flickers but the breaker doesn’t close, check the wiring to the sync-check relay output.
