Schneider Electric EOCR-SS Modules: EOCRSS-05RY7

Technical Dossier

Product Details And Specifications

Schneider Electric EOCR-SS Series Technical Notes

The Evolution of EOCR-SS Architecture

The EOCR-SS lineage originates from Samwha Electric's early solid-state relay development in South Korea during the late 1980s. The first-generation EOCR-SS units used discrete analog circuitry for current sensing, with fixed trip-class settings and limited adjustment range (typically 0.5–5 A or 3–30 A bands). These units were widely adopted in Asian heavy industry through the 1990s due to their low cost and robust construction relative to European alternatives.

The second generation, introduced in the mid-1990s, added phase-sequence detection and improved EMI immunity, addressing field failures in variable-frequency drive (VFD) environments. The suffix structure was standardized during this period: the numeric segment (e.g., 05, 1, 2, 5) denotes the maximum current range in amperes, while suffix letters encode output relay configuration (R = relay output), reset mode (Y = manual/auto selectable), and auxiliary contact count (7 = specific contact arrangement).

Following Schneider Electric's acquisition of the SE-Relays product line, the EOCR-SS series was integrated into the TeSys ecosystem documentation but retained its original part numbering for backward compatibility. Current production units are functionally equivalent to legacy variants but may differ in terminal block design and label language. Users migrating from legacy EOCR-SS to modern TeSys D or TeSys Deca overload relays must verify coil voltage, trip-class range, and auxiliary contact configuration before substitution, as direct pin-for-pin replacement is not guaranteed across all frame sizes.

EOCR-SS Full Catalog & Functionalities (SKU List)

The following SKUs represent the documented EOCR-SS production range. Each unit is a self-contained electronic overload relay with integrated current transformer sensing. Classification follows functional current range and output configuration.

Standard Current Range — Relay Output, Manual/Auto Reset:

• EOCRSS-05RY7: 0.5–5 A range, relay output, manual/auto reset, 7-pin base mount
• EOCRSS-1RY7: 1–10 A range, relay output, manual/auto reset, 7-pin base mount
• EOCRSS-2RY7: 2–20 A range, relay output, manual/auto reset, 7-pin base mount
• EOCRSS-5RY7: 5–50 A range, relay output, manual/auto reset, 7-pin base mount
• EOCRSS-10RY7: 10–100 A range, relay output, manual/auto reset, 7-pin base mount
• EOCRSS-30RY7: 30–300 A range (external CT required), relay output, manual/auto reset

Extended Range — With Ground Fault Detection:

• EOCRSS-05RY: 0.5–5 A, relay output, auto reset, standard base
• EOCRSS-1RY: 1–10 A, relay output, auto reset, standard base
• EOCRSS-2RY: 2–20 A, relay output, auto reset, standard base
• EOCRSS-5RY: 5–50 A, relay output, auto reset, standard base

Variants with Phase-Loss & Sequence Protection:

• EOCRSS-05RM7: 0.5–5 A, relay output, manual reset, 7-pin, phase-loss detection
• EOCRSS-1RM7: 1–10 A, relay output, manual reset, 7-pin, phase-loss detection
• EOCRSS-2RM7: 2–20 A, relay output, manual reset, 7-pin, phase-loss detection
• EOCRSS-5RM7: 5–50 A, relay output, manual reset, 7-pin, phase-loss detection
• EOCRSS-10RM7: 10–100 A, relay output, manual reset, 7-pin, phase-loss detection
• EOCRSS-30RM7: 30–300 A, relay output, manual reset, external CT, phase-loss detection

Quality Control for the EOCR-SS Range

EOCR-SS units present specific testing challenges due to their solid-state sensing circuitry and relay output stage. DriveKNMS applies the following test protocol to all EOCR-SS inventory prior to dispatch:

• Current injection test: Each unit is subjected to a calibrated AC current injection at 100%, 115%, and 125% of the rated trip threshold to verify trip-time accuracy against IEC 60947-4-1 Class 10 and Class 20 curves.
• Phase-loss simulation: For units with phase-loss detection (suffix -RM7), single-phase open-circuit conditions are simulated to confirm alarm relay activation within the specified response window.
• Output relay continuity: NO and NC contact resistance is measured under rated load to detect contact degradation in aged units.
• Reset function verification: Both manual and automatic reset modes are cycled to confirm selector switch integrity and internal latch mechanism operation.
• Insulation resistance: 500 V DC megger test applied between current-carrying terminals and relay output terminals to verify dielectric integrity.
• Visual and mechanical inspection: Terminal block condition, base-mount pin alignment, and enclosure integrity are checked against OEM reference units.