EOCR-SS Electronic Motor Protection Relay

Developed and manufactured by GOTOELE, a professional low-voltage electrical manufacturer in Zhejiang, China with more than 14 years of industry experience, this electronic motor protector integrates overload protection, motor stall protection, phase loss protection and three-phase current imbalance protection into one compact DIN rail mounted unit. It is widely used in pumps, fans, compressors, conveyors and OEM control cabinets where reliable motor protection and reduced maintenance downtime are required.

Working PrincipleEOCR-SS Electronic Motor Protection Relay is designed to protect small and medium three-phase AC motors from abnormal current conditions that may cause winding overheating, insulation aging and unexpected equipment shutdown.

Unlike conventional bimetal thermal overload relays that react slowly and are affected by ambient temperature, EOCR-SS continuously monitors motor operating current through a split clamp-on current transformer. When abnormal conditions such as overload, phase failure or current imbalance occur, the relay quickly disconnects the contactor control circuit to stop the motor and prevent further damage.

The split CT structure allows installation without removing existing power cables. This makes it especially suitable for equipment upgrades, old control cabinet renovation and OEM machinery where reducing installation time is important.

● Compact Design

● Multiple Protection Functions

● Wide Current Adjustment Range(10:1)

● Ammeter Function

● Trip Indication LED

● High Accuracy

● Manual Instantaneous Reset

● Electrical Remote Reset

● Test Function

● Ambient Insensitive

● Low Power Consumption

● Fail-safe Operation(No Volt Release)

Intelligent Protection Functions for Motor Safety

1. Accurate Overload and Stall Protection

During motor operation, excessive mechanical load, bearing blockage or equipment jamming can cause current rise beyond the normal operating range. EOCR-SS continuously detects motor current changes and activates protection after the preset delay time.

The adjustable LOAD setting allows users to match different motor rated currents accurately, while the O-TIME delay function prevents unnecessary shutdown caused by short-time current fluctuation.

This protection function is widely applied in conveyor systems, water pumps, ventilation equipment and small industrial machinery where unexpected motor overload may lead to production interruption.

2. Phase Loss Protection for Three-Phase Motors

Three-phase motors operating under phase loss conditions may experience excessive current in the remaining phases, resulting in rapid winding overheating and permanent motor damage.

EOCR-SS detects abnormal current distribution caused by phase failure, disconnected cables or contactor contact problems, and immediately interrupts the motor control circuit.

This function is especially valuable in areas with unstable power grids, agricultural facilities and outdoor equipment installations where phase loss risks are higher.

3. Three-Phase Current Unbalance Monitoring

Uneven current distribution between three phases is usually caused by winding problems, voltage imbalance or uneven mechanical loading.

EOCR-SS monitors current differences between phases and provides early protection before minor imbalance develops into serious motor failure.

Compared with traditional protection devices that only respond after severe overload occurs, electronic current monitoring helps maintenance teams identify potential risks earlier and reduce unexpected downtime.

4. Adjustable Startup Delay Function

Large startup current is normal when motors begin operation. Immediate overload protection during startup may cause unnecessary tripping.

The built-in D-TIME startup delay function allows motors to complete acceleration before entering normal protection mode. Users can adjust the delay according to different motor starting characteristics, ensuring reliable operation for equipment with higher starting torque requirements.

Application Experience and Project Verification

Motor Protection Upgrade Project in Vietnam Food Processing Factory

Based on GOTOELE's experience in low-voltage electrical manufacturing and global export projects, EOCR-SS has been applied in motor protection upgrades for industrial customers.

In March 2026, a food processing equipment manufacturer in Vietnam installed 120 units of EOCR-SS Electronic Motor Protection Relay in conveyor motor control cabinets.

The application environment included:

· Customer type: Food processing machinery manufacturer

· Installation location: Conveyor system control cabinets

· Motor power range: 0.75kW-2.2kW three-phase motors

· Working voltage: AC380V 50Hz

· Operating temperature: -10℃ to 45℃

· Daily operation time: Approximately 16 hours/day

· Motor start frequency: 50-80 times/day

After 12 months of continuous operation, the customer reported stable protection performance and reduced motor failure caused by overload and phase-loss problems. Compared with previous thermal overload protection solutions, maintenance intervention frequency was significantly reduced, improving production continuity.

This practical application demonstrates the reliability of EOCR-SS in high-frequency industrial motor operation environments.

Product Parameters

Product Advantages

1. Cable-Cutting-Free Installation Saves Retrofit Time

EOCR-SS adopts an openable split current transformer design. Installation technicians only need to clamp the CT onto existing motor cables without disconnecting wiring or modifying the power circuit.

This design greatly reduces installation difficulty for existing machines, especially suitable for factory equipment upgrades and control cabinet retrofitting projects.

2. Electronic Detection Improves Protection Accuracy

The electronic current sensing system provides faster and more stable protection compared with traditional thermal overload relays.

It avoids temperature influence and mechanical fatigue problems, maintaining consistent protection performance during long-term operation.

3. Flexible Adjustment Matches Different Motors

EOCR-SS provides independent adjustment of startup delay, operating current and trip delay parameters.

Users can configure protection settings according to different motor loads, starting conditions and application environments, improving compatibility with various industrial machines.

4. Compact DIN Rail Design Saves Cabinet Space

The modular structure allows direct installation inside standard electrical control cabinets.

Compared with installing separate current transformers and protection components, EOCR-SS provides a more compact solution and simplifies control system design.

Manufacturing and Quality Assurance

GOTOELE is a professional manufacturer and exporter specializing in low-voltage electrical products, including contactors, relays, circuit breakers, motor protection devices and industrial control components.

With more than 14 years of experience in electrical manufacturing, the company operates a production base in Liushi, Yueqing, Zhejiang, China. The factory covers more than 1600 square meters and includes professional production areas and quality inspection facilities.

During EOCR-SS production, GOTOELE performs strict inspections covering current detection accuracy, relay action response, terminal reliability and product aging tests.

Every batch follows ISO9001 quality management procedures, and products comply with CE certification requirements to ensure stable performance for international industrial applications.

Packaging and Delivery

EOCR-SS Electronic Motor Protection Relay is packed according to international export standards to prevent damage during transportation.

For bulk orders, GOTOELE provides efficient production scheduling with typical delivery times of 10-15 days. OEM customization services including logo printing, packaging design and parameter customization are available for global distributors and industrial equipment manufacturers.

FAQ

1. What is the difference between EOCR-SS and a traditional thermal overload relay?

EOCR-SS uses electronic current monitoring technology, providing higher protection accuracy and faster response compared with traditional thermal overload relays. It also supports split CT installation without cable cutting, making it more convenient for equipment upgrades.

2. Can EOCR-SS be installed on existing motor control cabinets?

Yes. The clamp-on current transformer allows installation directly on existing motor cables without removing wiring, making it suitable for old equipment renovation and maintenance projects.

3. What motors are suitable for EOCR-SS?

EOCR-SS is mainly designed for small three-phase AC motors, including pumps, fans, compressors, conveyors and OEM machinery with current requirements within the 0.5~5A range.

4. Does GOTOELE provide OEM customization?

Yes. GOTOELE supports OEM/ODM services including customized labels, packaging, specifications and electrical parameter requirements for different international markets.

GOTOELE combines professional electrical manufacturing capability, practical application experience and strict quality control systems to provide reliable motor protection solutions for global industrial customers. EOCR-SS Electronic Motor Protection Relay represents a cost-effective upgrade from traditional protection devices, helping industries improve equipment safety, reduce maintenance costs and achieve more stable production operation.