Woodward 9905-363 DSLC Synchronizer & Load Control

Woodward 9905-363 Digital Synchronizer and Load Control (DSLC)

The Woodward 9905-363 is a Digital Synchronizer and Load Control (DSLC™) unit designed for three-phase AC generator systems. Built specifically for complex marine switchboards, offshore installations, and critical continuous-power utility paralleling, the 9905-363 combines synchronizing, real load sharing (kW), reactive load control (kVAR/PF), dead-bus closing, and generator protective functions into a single ruggedized chassis.

Engineered for 240 Vac Open-Delta potential transformer (PT) sensing topologies and featuring a ±3.0 Vdc speed bias output, this full-function variant seamlessly bridges Woodward 2301A/D, 723PLUS, and digital speed governors directly with automatic voltage regulators (AVRs). Inter-module communication relies on a high-speed, noise-immune Echelon LonWorks network that enables multi-generator isochronous load sharing without analog droop or complex cross-current compensation transformers.

Model Details

• Manufacturer: Woodward
• Product Series: DSLC™ (Digital Synchronizer and Load Control)
• Part Number / MPN: 9905-363
• Feature Level: Full Function (Automatic Synchronizer, Real kW Load Control, Process Control, and Reactive kVAR / Power Factor Control)
• PT Sensing Configuration: Open Delta (3-Phase, 3-Wire)
• Nominal PT Voltage Input: 240 Vac line-to-line nominal
• Governor Speed Bias Output: ±3.0 Vdc analog bias signal
• AVR Voltage Bias Output: Dual-range ±1.0 Vdc / ±3.0 Vdc or pulse-width modulated interface
• Communication Protocol: Echelon LonWorks® twisted-pair differential network

Features

1. All-in-One Switchgear Integration: Combines slip-frequency automatic synchronization, dead-bus closure verification, proportional kW load sharing, and kVAR/PF voltage regulation within a single enclosure.
2. True RMS Multi-Phase Power Sensing: Digital sampling delivers high accuracy under non-linear loads, SCR drives, and variable-frequency auxiliary shipboard demands.
3. Deterministic LonWorks Network Bus: Eliminates complex analog cross-wiring by transmitting real/reactive load metrics, breaker statuses, and system sequencing over a single twisted pair.
4. Process & Base-Load Import/Export Control: Capable of controlling generator loading to maintain a fixed import/export power level across a tie-breaker when paired with a Woodward MSLC.
5. Integrated Generator Safeguards: On-board reverse power detection, over/under-voltage relays, phase angle mismatch limits, and fail-to-synchronize lockouts.

Technical Specifications

Compatibility

• Engine & Turbine Governors:
  • Woodward 2301A Speed & Load Control (using ±3 Vdc input)
  • Woodward 723PLUS, 733, and 825 Digital Controls
  • Woodward Peak 150 / 505 Steam Turbine Governors
  • Caterpillar ADEM series, Cummins PCC, MTU ADEC/MDEC (via analog bias modules)
• Automatic Voltage Regulators (AVRs):
  • Basler DECS-100, DECS-200, DECS-250, AVC63-12 / AVC125-10
  • Leroy Somer R448, R449, R450, D510
  • Stamford / Newage MX321, MX341, DM110
  • Marathon Electric DVR 2000E+
• System Master Controls:
  • Woodward MSLC (Master Synchronizer and Load Control, e.g., 9905-795 / 9907-006 series)

Frequently Asked Questions

What differentiates the Woodward 9905-363 from the 9905-355?

The 9905-363 is configured for 240 Vac Open-Delta transformer secondary configurations, whereas the 9905-355 is designed for 120/240 Vac Wye (Star) multi-wire configurations. Connecting the wrong unit will result in phase angular calculation errors and unstable load sharing.

Can the 9905-363 operate as an isolated standalone unit without LonWorks?

Yes. The 9905-363 can function as a standalone synchronizer and base-load controller via discrete analog/contact inputs without a LonWorks network. However, to execute peer-to-peer digital isochronous kW and kVAR load sharing between multiple running generators, the LonWorks network connection between modules is required.

How does the unit handle dead-bus closing?

The DSLC contains an internal dead-bus detection circuit. When the bus voltage is confirmed dead (below preset dead-bus threshold voltage) and the generator voltage is healthy, the control bypasses the dynamic phase-angle matching window and issues an immediate breaker closure command, ensuring critical switchboard recovery.

What is the direct modernization path if my 9905-363 fails and is obsolete?

Woodward provides the DSLC-2 conversion line. The direct mechanical and electrical upgrade uses the DSLC-2 Open Delta conversion chassis, pre-wired to match the footprint and terminal pattern of the 9905-363, replacing LonWorks cabling with industrial dual-redundant Ethernet.

Why is the ±3.0 Vdc speed bias output critical?

Most legacy Woodward governors (such as the 2301A) and digital speed controls utilize a standard analog ±3.0 Vdc bias input to adjust engine RPM. The 9905-363 directly interfaces with these controls without requiring external signal converters or potentiometer-motor drive boxes.