Schneider EOCR-SSD Series Modules: EOCR-SSD 05 EOCRSSD-05DF7

Technical Dossier

Product Details And Specifications

Schneider Electric EOCR-SSD Series Technical Notes

The Schneider Electric (formerly Samwha / SE) EOCR-SSD series represents a mature, widely deployed family of microprocessor-based electronic overload relays (EOCRs) used across global heavy industry. Installations span petrochemical complexes, nuclear auxiliary systems, offshore platforms, and continuous-process refineries where motor protection reliability is a non-negotiable operational parameter. The EOCR-SSD line provides phase-loss detection, ground-fault protection, and adjustable trip-class settings in a DIN-rail or panel-mount form factor, making it a standard specification item in MCC (Motor Control Center) builds across Asia-Pacific, the Middle East, and Eastern Europe. Its long production run — spanning from the early 2000s through the current decade — means a substantial installed base remains in service, driving sustained demand for both new units and certified replacement modules.

The Evolution of EOCR-SSD Architecture

The EOCR-SSD series evolved from Samwha Electric's earlier electromechanical EOCR product lines, which date to the 1980s. When Schneider Electric acquired distribution and branding rights for the EOCR range, the SSD sub-series was repositioned as the microprocessor-controlled tier, replacing analog trip circuits with digital sampling of current waveforms at the CT (current transformer) input stage.

Early SSD variants (pre-2005) used fixed-function ASICs with limited trip-class configurability. Mid-generation units (2005–2015) introduced DIP-switch selectable trip classes (5, 10, 20, 30) and added separate terminals for remote reset. The current production variants — including the EOCRSSD-05DF7 — incorporate LED diagnostic indicators, self-test routines on power-up, and improved EMC shielding to meet IEC 60947-4-1 requirements in high-noise industrial environments.

Compatibility note: The SSD series uses a proprietary CT wiring scheme. CT modules from the EOCR-SS or EOCR-SD lines are not interchangeable without adapter harnesses. Firmware versions are not field-upgradeable; functional changes require physical module replacement.

EOCR-SSD Full Catalog & Functionalities (SKU List)

The following SKUs represent verified, commonly stocked models within the EOCR-SSD series. Units are classified by current range and feature set.

EOCR-SSD 05 / EOCRSSD-05DF7: Microprocessor EOCR, 0.5–5A range, phase-loss & ground-fault, DIN rail, 110/220VAC coil — the primary subject of this listing.
EOCR-SSD 1: 1–10A setting range, standard trip class 10, panel-mount version with screw terminals.
EOCR-SSD 2: 2–20A range, adjustable trip class 5/10/20, suitable for mid-size pump motors.
EOCR-SSD 5: 5–50A range, external CT input, used in compressor and conveyor motor applications.
EOCR-SSD 10: 10–100A range, external CT, phase-sequence detection included.
EOCR-SSD 20: 20–200A range, heavy-duty motor protection for large HVAC and process pumps.
EOCR-SSD 30: 30–300A range, designed for high-inertia load starting in steel and mining plants.
EOCRSSD-05DF7: Variant suffix indicating 110VAC control voltage, DIN-rail foot, 7-pin relay output configuration.
EOCRSSD-1DF7: 1–10A, same DF7 terminal configuration, 110VAC.
EOCRSSD-2DF7: 2–20A, DF7 terminal block, 110VAC coil voltage.
EOCRSSD-5DF7: 5–50A, external CT, DF7 relay output, 110VAC.
EOCRSSD-05DF4: 0.5–5A, 220VAC coil, 4-pin relay output, panel-mount.
EOCRSSD-1DF4: 1–10A, 220VAC, 4-pin output, standard MCC replacement unit.
EOCRSSD-2DF4: 2–20A, 220VAC, 4-pin, used in water treatment motor control panels.
EOCRSSD-5DF4: 5–50A, 220VAC, external CT, 4-pin relay output, refinery-grade specification.
EOCRSSD-10DF7: 10–100A, 110VAC, DF7 terminal, phase-loss trip with manual/auto reset selection.
EOCRSSD-20DF7: 20–200A, 110VAC, DF7, suitable for large centrifugal pump protection in petrochemical plants.

Quality Control for the EOCR-SSD Range

The EOCR-SSD series presents specific test challenges due to its microprocessor-controlled trip logic and CT-coupled current sensing architecture. DriveKNMS applies the following verification protocol to all EOCR-SSD units prior to dispatch:

CT Input Calibration Check: Each unit is connected to a calibrated current injection bench. Trip thresholds are verified at 100%, 115%, and 200% of the set current value to confirm correct trip-class behavior.
Phase-Loss Simulation: Single-phase and two-phase loss conditions are injected to verify that the phase-loss detection circuit triggers within the specified response time (typically <2 seconds at full load).
Ground-Fault Sensitivity Test: A controlled ground-fault current is applied to confirm the earth-leakage detection threshold is within the factory-specified window.
Relay Output Continuity: NO and NC contacts on the trip relay are tested under rated load to confirm contact resistance is within specification.
Power-Up Self-Test Verification: The unit is powered on and the LED diagnostic sequence is observed to confirm the microprocessor self-test completes without fault codes.
Coil Voltage Tolerance Test: Control voltage is applied at 85% and 110% of rated voltage to verify stable operation across the specified tolerance band.