Description

---

　　Many products have not yet been listed online; please contact us for more information.

　　If the product model differs from the displayed image, the model number takes precedence. Please contact us for specific product photos; we can arrange for warehouse staff to take and send photos for verification.

　　We operate 76 shared warehouses worldwide, so it may sometimes take a few hours to provide you with an accurate response; we appreciate your understanding. Rest assured, we will address your inquiries as quickly as possible.

---

　　8440-1952 Alternative Names:

Mains Decoupling Controller 8440-1952

8440-1952 Digital Controller

Synchronizer Module 8440-1952

　　I. Operating Principle

The fundamental task of the synchronizer is to ensure that circuit closure occurs only when three conditions are simultaneously met (voltage difference, frequency difference, and phase difference all fall within permissible limits). Otherwise, the surge current at the moment of paralleling could be sufficient to damage the generator, transformer, and switchgear. The operating principle of the LS-521 comprises four layers:

1. Acquisition Layer (simultaneously monitoring System A and System B)

Voltage Measurement: Performs simultaneous True RMS measurements of the three-phase voltages (3 phases + neutral) for both System A and System B. It supports dual independent input ranges: a 100V range (rated 69/120V, max. 150V) and a 400V range (rated 277/480V, max. 600V). Accuracy is Class 1, with a linear range of 1.25 times the rated value;

Current Measurement: Measures System A three-phase currents (designed for 1A CTs; linear measurement range is 1.5 times the rated value; short-time withstand capability is 50 times the rated value for 1 second), used for determining power flow direction and calculating power;

Frequency Measurement: Measurement range of 30–85 Hz; compatible with 50/60 Hz systems;

Digital Inputs: 8 isolated digital inputs (8–40 VDC) for circuit breaker auxiliary contact feedback, interlocking signals, and remote commands.
       2. Synchronization and Decoupling Control Layer (Core)

Synchronization Check and Active Synchronization: Real-time calculation of voltage, frequency, and phase angle differences between the two sides. Supports both slip-frequency synchronization and phase-matching synchronization; automatically verifies voltage matching before closing the breaker and issues the close command within the permissible window—enabling “bumpless paralleling.”

Vector Group Adjustment: Compensates for fixed phase shifts caused by transformers (e.g., Δ/Y connections) via vector group configuration, ensuring accurate synchronization assessment.

Mains Decoupling: When installed on the incoming circuit breaker, it automatically detects mains faults (loss of voltage, undervoltage, frequency anomalies, phase shifts, rate of change of frequency [df/dt], etc.). It immediately issues a decoupling command to disconnect from the mains and sends a start signal to the easYgen generator set controller, executing an automatic power transfer from “mains failure” to “generator backup.”

Bus Section Load Control: Divides the power distribution system into up to 32 bus sections via bus-tie breakers. The LS-521 manages synchronization and load pickup/shedding for its section, broadcasting voltage, frequency, and phase angle reference values ​​to each easYgen unit via the CAN bus to achieve system-wide load sharing.

Operating Modes: AUTO and MANUAL; supports Stand-alone mode—functioning as a standalone synchro-check relay when not connected to easYgen units.

　　3. Protection Layer (ANSI-compliant)

Includes a comprehensive grid-side protection suite: over/undervoltage (59/27), over/underfrequency (81O/U), voltage asymmetry (47), phase shift (78), Rate of Change of Frequency/ROCOF (81), QV monitoring, time-characteristic voltage monitoring, and mains voltage rise protection compliant with VDE-AR-N 4105. Additional features include circuit breaker trip/close failure detection, synchronization timeout monitoring, voltage plausibility checks, and four freely configurable alarms.

　　4. Communication Layer

1 CAN bus port: A single CAN cable connects the LS-521 to all easYgen units, transmitting all AC measurement signals, I/O statuses, and flags—a key design feature that significantly simplifies wiring and reduces costs;

1 RS-485 port: For remote control and SCADA visualization;

LogicsManager: Built-in programmable soft logic allowing for the free combination of Boolean logic and timers to manage control and relay functions;

Event logging: Stores up to 300 events; features a battery-backed real-time clock with automatic date/time synchronization between the LS-5 and easYgen units; also includes circuit breaker closing counters and energy counters.

---

　　II. Operation Methods

1. Front Panel Operation (Local)

Graphic LCD and soft keys; MAN (Manual), AUTO, and LAMP TEST buttons on the left; directional navigation keys on the right; multi-language support (including Chinese);

Real-time monitoring of voltage, frequency, phase difference, power, and synchronization status on both sides; includes keypad lock to prevent accidental operation, with parameter modification protected by a password. 2. Role Configuration (Engineer-level setup): One hardware unit supports three roles, selectable via software:

Standalone synchro-check relay (verifies conditions only; does not directly command closing);

Mains incomer circuit breaker control (includes fault detection, decoupling, and start signal transmission to easYgen);

Bus-tie circuit breaker control (synchronous closing and bus-tie operation between two busbar sections). Configuration is performed using the ToolKit PC software (via DPC cable): select application mode; set voltage levels, CT ratio (1A nominal), synchro-check windows (voltage/frequency/phase difference), vector group, protection settings and time delays, CAN/RS-485 parameters, LogicsManager logic, etc. The series offers pre-configured application modes, significantly simplifying the setup of complex multi-breaker systems.

3. Remote Operation: Full remote control capabilities via CAN or RS-485, including remote closing/opening commands, mode switching, parameter adjustment, and status monitoring; supports integration with power monitoring SCADA systems.

---

      III. Important Notes (Engineer’s Advisory)

Installation and Wiring

Power Supply: 12/24V DC (8–40 VDC range), power consumption approx. 6W; verify polarity and install appropriate fusing; turn off the charging unit before connecting or disconnecting the battery.

Voltage Ranges: The 120V and 480V ranges utilize separate terminal sets; verify the system voltage level before wiring, as incorrect connection will damage the measurement circuit (max. 150V for the 120V range; max. 600V for the 480V range).

CT Circuit (Critical): Model 8440-1952 is designed for 1A CTs and must be matched with current transformers having a 1A secondary rating; connecting a 5A transformer is strictly prohibited (this will cause overcurrent damage or severe measurement inaccuracy). Secondary open-circuiting is also strictly prohibited; always short-circuit the terminals before maintenance.

Phase Sequence and Polarity: Phase assignment and current polarity for System A/B must be correctly matched, as synchronization detection and power calculations rely entirely on this; verify using a phase sequence meter before energizing the system—incorrect wiring here is the most common cause of accidents during paralleling operations. Commissioning and Operation

Perform initial commissioning via a step-by-step verification process: “no-load test run” → “synchronization check only” → “manual closing” → “automatic closing”;

Configure the synchronization closing window based on the actual circuit breaker closing time: an excessively wide window causes shock during paralleling, while an excessively narrow window leads to frequent closing failures;

Configure correct vector group compensation when transformers are present; use the dedicated “Test” mode for mains decoupling tests to ensure a reliable power supply for the downstream load;

Implement critical hardware protections (e.g., overspeed, reverse power) independently of the controller; this is a mandatory requirement in the Woodward manual.

Operation and Maintenance

Environment: Operating temperature -20 to +70°C, storage temperature -30 to +80°C, humidity 95% (non-condensing); front panel rating IP66/IP54 depending on the mounting method;

Periodically review event logs and closing counters to verify synchronization performance; when replacing spare parts, verify the order number (1A version: 8440-1952, 5A version: 8440-1947; V2 version: 8440-2178/8440-2150) and ensure software version compatibility with the easYgen unit.

---

       IV. Application Areas

Independent synchro-check (prevention of incorrect paralleling): Functions as a synchro-check relay to prevent operators from accidentally closing the circuit breaker when conditions are not met;

Mains incomer circuit breaker control / AMF (Automatic Mains Failure) switching: Works with easYgen-3400XT/3500XT genset controllers to handle automatic disconnection upon mains failure, automatic generator takeover, and automatic reconnection upon mains restoration—core equipment for facilities requiring uninterrupted power, such as hospitals, data centers, airports, and financial institutions;

Bus-tie circuit breaker control: Manages interconnection, sectionalized operation, and load transfer between two or more busbar sections; suitable for power distribution in large industrial complexes and business parks;

Complex power management systems: Supports complex configurations involving multiple mains incomers, bus-ties, and generator circuit breakers; enables networking of up to 16 LS-5 units and 32 easYgen units across up to 32 busbar sections to achieve system-wide automatic power management;

Grid-parallel applications in Germany and Europe: Complies with VDE-AR-N 4105 / BDEW grid codes; used for protection at the grid connection point for distributed energy resources;

Import/Export control: Works with the genset system to control purchased or exported power, enabling demand management and peak shaving.

---

       V. Key Benefits

Transforms “impactful paralleling” into “seamless closing”: Triple synchronization checks (voltage, frequency, and phase) combined with active synchronization adjustment eliminate closing under unsafe conditions, thereby protecting generators, transformers, and circuit breakers.

Replaces “manual judgment” with “automated safety”: Features automatic decoupling upon grid failure and automatic start-signal generation, enabling unattended power source switching.

Simplifies “complex wiring” to a “single cable”: A single CAN bus handles signal transmission between all LS-5 units and easYgen controllers, saving panel builders time and costs on wiring, cabinet space, and commissioning.

One hardware platform, multiple roles: Software-based switching between synchronization check, incoming feeder control, and bus-tie control ensures unified inventory and high standardization.

Meets grid requirements: Built-in protections for ROCOF, phase shift, and grid overvoltage ensure compliance with German and international grid standards for worry-free grid connection.

Scalable and customizable: Supports up to 32 busbar segments and 16 LS-5 units; features LogicsManager for flexible logic programming and CAN/RS-485 remote monitoring, covering everything from small ATS setups to large-scale, multi-feeder power management systems.

---

Model recommendation:
EASYGEN 3500XT 8440-2085
8440-1800
8440-1925
8440-1934
8440-1546
8440-1894
8440-2096
8440-2077
WOODWARD 8440-1809
8440-2050
8440-1878
8440-2050
9907-1228-CPC
9907-205
9907-018
9907-163
9907-163
9907-175
9907-149
9907-162 
9907-164
9907-165 
5466-409
5448-890
8440-2047
SPM-D11 8440-1703
SPM-D11 8440-1706
5463-375
 5463-384
8271-147 
8271-872
5463-397
More……