Chint JR36-63 Thermal Overload Relay

  The Chint JR36-63 Thermal Overload Relay is an overload and phase-failure protection device specifically designed for three-phase AC motors. It is suitable for circuits with a rated voltage up to 690V and a current setting range of 14-63A. Below are its core features and application scenarios:

I. Core Technical Parameters

1. Basic Performance

Rated Current: 63A (frame size rating), supporting multiple thermal element specifications: 14-22A, 20-32A, 28-45A, 40-63A. The rated current of the motor can be accurately matched by rotating the adjustment knob.

Tripping Characteristic: Tripping class is 20 (6sTp ≤ 20s), complying with the IEC 60947-4-1 standard, ensuring rapid circuit interruption to protect the motor in case of overload.

Phase-Failure Protection: Adopting a differential bimetallic strip structure, it can detect power failure in any phase and trigger tripping immediately to prevent the motor from being burned due to single-phase operation.

2. Electrical and Mechanical Characteristics

Auxiliary Contacts: Standard configuration of 1 normally open (NO) + 1 normally closed (NC) contact. The rated current is 0.47A at AC-15 380V, which can directly control the contactor coil or transmit fault signals.

Temperature Compensation: Compensates for ambient temperature changes through a built-in bimetallic strip, ensuring stable protection characteristics within the range of -5℃ ~ +40℃.

Reset Method: Supports manual/automatic reset switching. The default setting at the factory is automatic reset; manual reset can be enabled by adjusting the screw if needed.

3. Installation and Connection

Installation Method: Independent installation, which needs to be fixed in the control cabinet with M6 screws. It is recommended that the inclination angle between the installation surface and the vertical plane does not exceed 5°.

Wiring Specifications: The main circuit supports 6-16mm² single-core or stranded wires, and the auxiliary circuit supports 2×(0.5-1)mm² wires. The connecting screws are M3 and M6.

II. Typical Application Scenarios

1. Industrial Motor Protection

- Suitable for three-phase asynchronous motors with a power range of approximately 7.5-30kW (such as conveyor belts, water pumps, fans, etc.). By monitoring changes in motor current, it quickly cuts off the power supply in case of overload (tripping within 2 hours when the current is 1.15 times the rated current) or phase failure.

- For example, for a 15kW, 380V motor with a rated current of 30A, the JR36-63 with a specification of 28-45A can be selected, and the set current can be adjusted to 30A to achieve precise protection.

2. Traditional Control Systems

- Can be combined with Chint CJT1 series contactors to form a QC36 type electromagnetic starter, which is widely used in traditional industrial control circuits that require high reliability but no intelligent functions.

- Compared with electronic relays, it has a simple mechanical structure and low cost, making it suitable for equipment transformation in small and medium-sized enterprises with limited budgets.

3. Adaptability to Special Environments

- Meets the requirements of industrial environments with an altitude ≤ 2000m and pollution degree 3, and can operate stably in places with a small amount of dust but no corrosive gases.

- For example, in the control of belt conveyors in cement plants, its dust-proof design can effectively avoid misoperation caused by dust accumulation.

III. Selection and Alternative Solutions

1. Key Selection Points

Current Matching: Select the thermal element specification according to the rated current of the motor, ensuring that the set current covers 1.05-1.1 times the actual operating current of the motor. For example, a 40A motor should be matched with the 40-63A specification.

Ambient Temperature: If the ambient temperature is higher than 40℃ for a long time, derating is required (for example, a relay with a rated current of 63A is recommended to be derated to 50A at 80% of its rated value when used at 50℃).

2. Recommendations for Alternative Models

NXR Series: Chint's new generation of electronic thermal overload relays, supporting plug-in installation, wide-range current setting (0.1-630A) and intelligent diagnosis functions. It has higher action accuracy and supports quick connection with NXC contactors, making it suitable for new projects or upgrade transformations.

Comparative Advantages: The NXR series has tripping characteristics that are more in line with international standards, a wider temperature compensation range (-25℃ ~ +70℃), and optional protective covers and auxiliary contact expansion modules.

IV. Installation and Maintenance Recommendations

1. Installation Precautions

Direction Requirement: Must be installed vertically according to the direction marked on the product to avoid misoperation caused by uneven heating of the bimetallic strip due to inclination.

Wire Selection: The cross-sectional area of the main circuit wire should match the motor load. Wires that are too thin will cause heating and misoperation, while wires that are too thick may delay tripping.

2. Daily Maintenance

Regular Inspection: Clean the dust on the surface of the relay every quarter, check whether the wiring terminals are loose, and test the sensitivity of the reset button.

Service Life Evaluation: The mechanical service life is approximately 100,000 times. If frequent tripping or contact ablation occurs, it is recommended to replace the relay in a timely manner to ensure the reliability of protection.

V. Market Price and Procurement Channels

Reference Price: The price is approximately 23 yuan (2025 data) (contact via WhatsApp: 0086-13811255435). The specific price varies by specification and distributor. For bulk purchases, you can contact via WhatsApp: 0086-13811255435 to get a better price.

Authenticity Verification: Scan the barcode or QR code on the product surface using the Chint official website applet to query the authenticity and avoid purchasing counterfeit products.

Summary

As a classic bimetallic strip-type thermal overload relay of Chint, the JR36-63 remains a mainstream choice for traditional industrial motor protection due to its stable performance, low cost, and wide compatibility. Although it is gradually being replaced by new models such as the NXR series, its advantages in reliability and economy make it still competitive in the maintenance of existing equipment and small-to-medium-sized projects. When selecting a model, users need to balance performance and cost according to specific needs. If intelligent functions or long-term stability are required, the NXR series is recommended as a priority; if the budget is limited and cost-effectiveness is pursued, the JR36-63 is still a reliable option.