PG OPR-SS3-120 Electronic Motor Overload Relay

The GOTOELE PG OPR-SS3-120 Electronic Motor Overload Relay is developed as an upgraded protection solution for three-phase AC motors. Installed between the AC contactor and motor load, it continuously monitors motor current conditions and disconnects the control circuit when abnormal operating situations occur, helping prevent motor overheating, winding damage, and unexpected equipment downtime.

Unlike conventional bimetal thermal overload relays that rely on thermal deformation for protection, the PG OPR-SS3-120 adopts electronic current detection technology to achieve faster response and more accurate fault identification. It reduces the impact of ambient temperature changes and maintains consistent protection performance during long-term industrial operation.

With a wide adjustable current range of 10-120A, the device can match different motor capacities and operating conditions. Three independent adjustment functions allow users to set motor load current, startup delay time, and fault trip delay time according to actual application requirements, improving system reliability while reducing unnecessary shutdowns.

Upgraded Alternative to Traditional Thermal Overload Relays

In traditional motor protection systems, thermal overload relays are commonly used to prevent motor damage caused by excessive current. However, long-term thermal operation may lead to slower response, reduced accuracy, and limited adjustment flexibility.

The PG OPR-SS3-120 Electronic Motor Overload Relay provides a more advanced protection method by using electronic sensing technology. It can accurately monitor motor operating conditions without being affected by repeated thermal cycles, making it especially suitable for industrial equipment requiring continuous operation and reliable protection.

The adjustable LOAD setting allows precise current matching for different motors, while the startup delay function prevents false tripping caused by temporary starting current. The trip delay function helps distinguish between short-term fluctuations and actual faults, improving operational stability.

Multiple Motor Protection Functions

The PG OPR-SS3-120 integrates several protection functions into one compact device:

Overload and Stall Protection

When a motor operates under excessive mechanical load, becomes blocked, or experiences abnormal current increases, the overload protection function detects the condition and disconnects the control circuit after the preset delay time. This helps prevent overheating and damage to motor windings.

Phase Loss Protection

Phase loss is one of the major causes of three-phase motor failure. The PG OPR-SS3-120 can detect missing phase conditions caused by cable faults, fuse failures, or contact problems, quickly stopping the motor before serious damage occurs.

Three-Phase Current Unbalance Protection

Uneven current distribution between three phases may cause excessive heating and shorten motor service life. The device monitors current balance and provides protection against long-term unbalanced operation.

Startup Delay Protection

Motor startup current can temporarily rise several times above the rated current. The adjustable startup delay function allows the motor to complete acceleration without unnecessary tripping, making it suitable for heavy-load starting applications.

Typical Application Scenarios

Industrial Pump Systems

The PG OPR-SS3-120 is widely used in water pumps, circulation pumps, drainage systems, and industrial pumping equipment. It protects motors from overload, phase failure, and abnormal current conditions during continuous operation.

HVAC and Refrigeration Equipment

For compressors, cooling tower fans, and ventilation motors, stable motor operation is critical. This electronic overload relay provides reliable protection against overload and stall conditions caused by mechanical problems or system abnormalities.

Manufacturing Automation Equipment

Production lines, conveyor systems, machine tools, and automated equipment often require motors to operate continuously. The PG OPR-SS3-120 helps reduce unexpected downtime by providing real-time motor protection.

Agricultural and Outdoor Equipment

Agricultural irrigation pumps and ventilation systems may operate in environments with unstable power conditions. Phase loss protection and adjustable delay functions help improve equipment reliability and reduce maintenance costs.

Practical Application Experience

In an industrial water pumping project, the PG OPR-SS3-120 Electronic Motor Overload Relay was installed inside the motor control cabinet to protect three-phase pump motors operating under variable load conditions.

During daily operation, the device continuously monitored motor current changes and successfully identified abnormal load increases caused by mechanical resistance changes. The adjustable protection delay avoided unnecessary shutdowns during normal startup, while fault protection functions helped prevent motor damage during abnormal conditions.

The application demonstrated the value of electronic motor protection in improving equipment safety, reducing maintenance frequency, and extending motor service life.

Core Parameters

Core Advantages

1. Higher Protection Accuracy Than Traditional Thermal Relays

The electronic sensing system provides stable current detection performance and avoids accuracy changes caused by thermal aging. It maintains reliable protection even under long-term industrial operation.

2. Adjustable Settings for Different Motor Applications

With independent adjustment of current threshold, startup delay, and fault trip delay, the PG OPR-SS3-120 can be configured for different motor sizes and operating environments, improving compatibility across various industrial applications.

3. Integrated Protection Saves Cabinet Space

By combining multiple protection functions into a single module, the device reduces the requirement for additional protection components and simplifies control cabinet wiring. Its standard DIN-rail installation allows easy integration into existing systems.

4. Reliable OEM Solution for Industrial Equipment Manufacturers

GOTOELE provides OEM customization services including product labeling, packaging design, and parameter adjustment. The PG OPR-SS3-120 is suitable for distributors, electrical panel builders, and industrial equipment manufacturers looking for stable motor protection solutions.

Specification

Production and Quality Control

GOTOELE manufactures the PG OPR-SS3-120 Electronic Motor Overload Relay in Zhejiang, China, with professional production processes and strict quality management systems.

Each product undergoes inspection procedures including current detection accuracy testing, protection function testing, terminal reliability inspection, and operational performance verification before shipment. Following ISO9001 quality management standards, GOTOELE ensures consistent product quality and reliable performance for global industrial customers.Packaging and DeliveryThe PG OPR-SS3-120 Electronic Motor Overload Relay uses export-standard packaging materials to prevent damage during transportation. GOTOELE supports bulk supply, OEM customization, customized labeling, and flexible delivery solutions to meet the requirements of international industrial customers.

FAQ

Q1: What is the difference between an electronic overload relay and a thermal overload relay?

An electronic overload relay uses current sensing technology to provide faster response, higher accuracy, and wider adjustment options. It is less affected by ambient temperature changes and is suitable for modern industrial motor protection systems.

Q2: Can the PG OPR-SS3-120 protect motors from phase loss?

Yes. The device includes phase loss protection and can detect abnormal three-phase conditions to disconnect the control circuit and prevent motor damage.

Q3: Is the PG OPR-SS3-120 suitable for different motor sizes?

Yes. With an adjustable current range of 10-120A, it can be configured for different three-phase motor applications, including pumps, fans, compressors, and automation equipment.

Q4: Does GOTOELE support OEM customization?

Yes. GOTOELE provides OEM services including logo printing, customized packaging, and product parameter customization according to customer requirements.

GOTOELE provides global industrial customers with reliable motor protection solutions through professional manufacturing capability, strict quality control, and practical application experience. The PG OPR-SS3-120 Electronic Motor Overload Relay helps improve equipment safety, reduce maintenance costs, and support stable operation of industrial automation systems.