Woodward 8440-1706 A | SPM-D11/LSXR Load Share Synchronizer, 12/24 VDC

Description

Key Technical Specifications

The OEM product specification identifies the SPM-D11/LSXR configuration as supporting generator and bus voltage measurement, generator current measurement, automatic synchronization, load/reactive-power sharing, isolated operation, dead-bus closing, and PC-based parameter configuration.

Product Introduction

Woodward 8440-1706 A Product Introduction

The Woodward 8440-1706 A SPM-D11/LSXR is a microprocessor-based synchronizer designed for generator paralleling applications. It monitors generator and bus electrical quantities, controls synchronization, and provides functions for load distribution and generator operation in parallel power systems.

The LSXR configuration goes beyond basic breaker synchronization. It supports load and reactive-power sharing, isolated operation, dead-bus closing, and generator protection functions. For an existing generator panel, the exact CT/VT ratios, control-voltage variant, and configured operating mode should be verified before replacement.

Application Scenarios & Field Pitfalls (The Engineer’s Perspective)

Engineering Pain Point

A generator can be electrically healthy and still refuse to close onto a live bus. A small frequency, voltage, or phase-angle mismatch is enough to block synchronization or create an unacceptable closing transient. The SPM-D11 sits directly in that part of the control sequence, so configuration errors here can become generator-startup problems rather than simple instrumentation faults.

8440-1706

Typical Applications

• Diesel Generator Plants — Automatic synchronization and load sharing of multiple generator sets operating in parallel.
• Power Generation — Generator-to-bus synchronization with active and reactive load sharing.
• Industrial Plants — Standby generator systems requiring automatic transfer and controlled paralleling.
• Marine / Distributed Generation — Generator paralleling and isolated-operation control where multiple sets share a common electrical bus.

Technical Pitfalls to Avoid

1. Verify the CT and VT configuration before commissioning.
   The 8440-1706 configuration is associated with 120 VAC voltage measurement and ../5 A current measurement. A controller configured for a different CT or voltage arrangement is not interchangeable merely because the front panel looks identical.
2. Do not confuse SPM-D11/LSR with /LSXR.
   The LSXR configuration adds functions such as load/reactive-power sharing and additional control capabilities. Woodward’s ordering table assigns different part numbers to these configurations.
3. Check the control-power version.
   The family includes both 12/24 VDC and 24 VDC variants. The 8440-1706 belongs to the 12/24 VDC group. Confirm the actual panel supply before energizing a replacement.
4. Check breaker logic before changing parameters.
   Synchronizer settings affect the actual breaker-closing sequence. Do not copy parameter values from another generator panel without confirming CT ratios, VT ratios, breaker timing, slip frequency, voltage matching, and governor/AVR response.
5. Separate synchronizing faults from governor/AVR faults.
   If the commands speed or voltage corrections but the generator does not respond correctly, the problem may be in the governor, AVR, actuator, or wiring rather than the synchronizer itself.

Related Products

• Woodward 8440-1703 — /LSXR, 120 VAC / 1 A CT
  Same general /LSXR function, but intended for ../1 A CT measurement. It should not be substituted for 8440-1706 where the generator uses 5 A CT secondary circuits.
• Woodward 8440-1705 — /LSR, 120 VAC / 5 A CT
  Similar voltage/current measurement arrangement but the LSR configuration differs from LSXR in available control functions. Useful when the application does not require the full LSXR feature set.
• Woodward 8440-1702 — /LSR, 120 VAC / 1 A CT
  1 A CT version of the LSR configuration. Applicable to generator installations using 1 A secondary CTs.
• Woodward 8440-1666 — /LSXR, 400 VAC / 5 A CT
  /LSXR variant for systems using direct 400 VAC voltage measurement with 5 A CT inputs. It is an important alternative when the generator voltage architecture differs from the 120 VAC VT arrangement.
• Woodward 8440-1668 — /LSR, 400 VAC / 5 A CT
  Similar 400 VAC measurement configuration with the LSR feature set. Selection depends on required synchronizing and load-sharing functions.
• Woodward 8440-1708 — /LSR, 24 VDC / 1 A CT
  24 VDC control-power variant using 1 A CT measurement. Applicable to installations with the corresponding configuration.
• Woodward SPM-D2-1115B/LSXR 8440-2165
  Newer SPM-D2 successor associated with the 8440-1706 configuration. It is relevant to lifecycle replacement projects, but migration requires checking wiring, configuration, and application requirements rather than assuming a direct drop-in replacement.
• Woodward EasyGen Generator Controllers
  These controllers combine generator-set control functions that may overlap with portions of a standalone synchronizer architecture. They are alternatives for new generator-control designs, not automatic replacements for an installed .
• Woodward 2301 / Load Sharing Controls
  Complementary governor/load-sharing hardware used in generator systems where speed control and synchronizing functions are separated across multiple control devices.