Schneider EOCR-SSD-05S System-Ready Overload Relay for EOCR Architecture

Schneider EOCR-SSD-05S System-Ready Overload Relay for EOCR Architecture

In modern industrial automation, motor protection is not an isolated function — it is a critical node within a layered control system architecture. The Schneider EOCR-SSD-05S (also referenced as EOCRSSD-05DF7) is a solid-state electronic overload relay engineered to deliver precise, reliable motor protection within Schneider Electric’s EOCR platform. Designed for seamless Contextual Integration across control, I/O, power, and field device layers, this relay ensures that your automation system maintains operational continuity, fault transparency, and long-term maintainability.

Unlike traditional thermal overload relays, the EOCR-SSD-05S employs solid-state sensing technology to monitor motor current with high accuracy across a 0.5–5A adjustment range. Its trip-free reset mechanism and built-in phase-loss detection make it a dependable component in systems where unplanned downtime carries significant operational cost. Whether deployed in a standalone motor starter or integrated into a multi-drive control cabinet, the EOCR-SSD-05S contributes to system-wide fault isolation and diagnostic clarity.

Architecture Specification Table

Coordinated Control System Design

The EOCR-SSD-05S is most effective when understood as part of a complete motor control and protection architecture. In a typical Schneider Electric-based control cabinet, the relay operates downstream of a Schneider TeSys D LC1D contactor, which handles the switching function, while the EOCR-SSD-05S continuously monitors current to detect abnormal conditions before they escalate into motor failure. This pairing is a standard configuration in pump stations, conveyor systems, and HVAC motor control centers.

At the control layer, a Schneider Modicon M221 or M241 PLC may receive fault signals from the EOCR-SSD-05S via hardwired digital inputs or, when equipped with an optional communication module, via Modbus RTU. This enables the controller to log fault events, trigger alarms, and initiate automatic restart sequences without operator intervention. For larger systems, the Modicon M340 or M580 CPU can aggregate fault data from multiple EOCR relays across a production line, providing centralized diagnostics through a Schneider HMIGTO or HMISCU HMI panel.

On the power distribution side, the EOCR-SSD-05S is typically installed in conjunction with a Schneider GV2ME or GV3ME motor circuit breaker, which provides short-circuit protection upstream. This two-device combination — circuit breaker plus electronic overload relay — is a widely adopted architecture in IEC-compliant motor control panels, offering both instantaneous fault clearing and time-delayed thermal protection in a compact footprint.

For systems requiring redundancy or remote monitoring, the EOCR-i Series communication adapter can be paired with the SSD-05S to enable real-time current data transmission over RS-485 Modbus networks. This is particularly valuable in unmanned substations, water treatment facilities, and offshore platforms where physical access for fault diagnosis is limited. The relay’s output contacts can also interface directly with Schneider Zelio Logic smart relays for simple local interlocking without a full PLC.

In multi-motor applications, the EOCR-SSD-05S can be deployed alongside EOCR-SS, EOCR-3DM, and EOCR-FDM series relays to create a unified motor protection strategy across different current ranges and protection profiles. This consistency within the EOCR platform simplifies spare parts management, reduces technician training requirements, and ensures that fault behavior is predictable and well-documented across the entire installation.

Application in Layered Automation Systems

The EOCR-SSD-05S is deployed across a wide range of industrial sectors where motor reliability is non-negotiable. In water and wastewater treatment plants, it protects submersible pump motors from dry-run conditions and phase loss caused by supply irregularities — a common failure mode in remote pumping stations. Its auto-reset capability allows the system to recover from transient faults without requiring a site visit, reducing operational costs significantly.

In petrochemical and refinery applications, the relay is installed in motor control centers (MCCs) protecting agitators, compressors, and cooling tower fans. The solid-state design eliminates the mechanical wear associated with bimetallic relays, making it suitable for environments with high ambient temperatures and vibration. The phase-unbalance detection function is particularly critical in these settings, where unbalanced supply voltages can cause accelerated motor winding degradation.

For mining and metallurgical operations, the EOCR-SSD-05S is used in conveyor drive panels, crusher motor starters, and ventilation fan control systems. Its wide current adjustment range and selectable trip class allow engineers to fine-tune protection settings to match the specific load characteristics of each motor, reducing nuisance tripping while maintaining adequate protection margins.

In packaging and food processing lines, the relay is integrated into servo-adjacent motor control panels where precise fault isolation is required to prevent product loss during unplanned stops. The relay’s fast response to locked-rotor conditions helps protect motors in applications with frequent start-stop cycles and high inertia loads.

Architecture Engineering FAQ

Q1: Is the EOCR-SSD-05S compatible with Schneider TeSys D contactors for direct-on-line (DOL) starter configurations?
Yes. The EOCR-SSD-05S is designed to work in series with TeSys D series contactors (LC1D09 through LC1D38) in standard DOL and reversing starter configurations. The relay’s output NC contact is wired into the contactor coil control circuit, ensuring that a trip event de-energizes the contactor and disconnects the motor from the supply. This is a fully IEC 60947-4-1 compliant configuration.

Q2: Can the EOCR-SSD-05S be integrated into a Modbus RTU network for remote monitoring?
The base EOCR-SSD-05S model does not include a built-in communication port. However, Schneider Electric offers the EOCR-i Series communication adapter, which can be connected to compatible EOCR relays to enable Modbus RTU communication over RS-485. This allows current values, fault codes, and relay status to be read by a Modicon PLC or SCADA system in real time. Confirm compatibility with your specific EOCR-i module variant before installation.

Q3: What does the 12-Month Warranty cover, and how is it handled by ZYPLC?
All EOCR-SSD-05S units supplied by ZYPLC are covered by a 12-Month Warranty from the date of shipment. This warranty covers manufacturing defects, premature component failure under normal operating conditions, and functional non-conformance to published specifications. In the event of a warranty claim, ZYPLC will arrange for replacement or repair at no additional cost. Contact our technical team at plc.sales@zyplc.com or +86 19859288691 to initiate a warranty claim or request pre-shipment inspection documentation.

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