Chint NXR series thermal overload relays

   The Chint NXR series thermal overload relays are core protection devices specially designed for industrial motor control. They feature high-precision overload protection, phase failure detection, and flexible installation methods, and are widely used in fields such as power, machinery manufacturing, and automated production lines. The following is a detailed description of its technical parameters, application scenarios, and selection suggestions: CHINT circuit breaker price

I. Core Technical Parameters and Functions

1. **Protection Performance*CHINT contactor price*

   - **Overload Protection**: Based on the principle of the thermal effect of the bimetallic strip, it monitors the motor current in real time. When the load exceeds 1.15 times the set current, it will trip and stop within 1 hour (in compliance with the IEC 60947-4-1 standard).

   - **Phase Failure Protection**: It detects the unbalance of the three-phase current. When the current of a certain phase is lower than 50% of the set value, it will trigger tripping within 2 seconds.CHINT surge protector price

   - **Temperature Compensation**: With a built-in thermal sensitive element, it automatically corrects the influence of the ambient temperature on the protection characteristics (the operating temperature range is from -5°C to 55°C).

2. **Models and Setting Ranges**

3. **Electrical Characteristics**

   - **Rated Voltage**: AC 380V/400V/440V/690V (supports wide voltage input).

   - **Reset Mode**: Automatic reset (within 5 seconds) or manual reset (requires pressing the reset button).

   - **Mechanical Life**: More than 1 million times, Electrical Life (AC-3): 100,000 times.

4. **Certification and Compliance**

   - It complies with the GB 14048.4 and IEC 60947-4-1 standards, has passed the CCC and CE certifications, and supports the RoHS environmental protection directive.

II. Typical Application Scenarios

1. **Industrial Motor Control**

   - **Fans/Pumps and Other Equipment**: To prevent overload caused by impeller blockage or bearing wear (for example, it can be used in combination with Chint NXC contactors to achieve start-stop control).

   - **Compressors/Conveyor Belts**: Short-term overload protection under frequent start-stop working conditions (such as injection molding machines and packaging machinery).

   - **Special Environments**: It supports operation without derating below an altitude of 3000 meters and is suitable for harsh environments such as mines and chemical plants.

2. **Power Load Protection**

   - **Resistance Furnaces/Heating Equipment**: It supports a non-inductive load of 200A under the AC-1 category and needs to be used in combination with a fuse to achieve short-circuit protection.

   - **Capacitor Banks**: To control the inrush current during switching (the AC-1 usage category needs to be selected).

3. **Automation Systems**

   - **PLC Control**: Through the auxiliary contacts (1NO + 1NC), the fault signal is fed back to the PLC to trigger shutdown or alarm.

   - **Energy Management**: It is compatible with the power monitoring systems of brands such as Schneider and ABB and supports Modbus communication (a communication module needs to be optionally configured).

 III. Installation and Selection Guidelines

1. **Installation Methods**

   - **Plug-in Installation**: It can be directly combined with Chint NXC contactors (such as NXC-25 and NXC-100) to save cabinet space (a special installation base is required).

   - **Rail Installation**: It supports the 35mm standard DIN rail. When fixing it independently, at least a 50mm spacing should be reserved to ensure heat dissipation.

2. **Wiring Specifications**

   - **Main Circuit**: Connect the three-phase power supply (L1/L2/L3) to the inlet terminal, and connect the motor to the outlet terminal (it is recommended to use copper core wires with a cross-sectional area of more than 6mm²).

   - **Control Circuit**: Connect the contactor coil (A1/A2) in series with the normally closed contact (NC) of the thermal overload relay to cut off the control circuit when an overload occurs.

   - **Auxiliary Contacts**: The normally open contact (NO) can be used for remote signal indication, and the normally closed contact (NC) is used for interlock protection (such as interlocking in the forward and reverse rotation circuits).

3. **Selection Key Points**

   - **Current Matching**: Select the model of the thermal overload relay according to the rated current of the motor. The setting current range should cover 1.05 to 1.15 times the rated current of the motor. For example, for a 15kW motor (rated current 30A), the NXR-100 (setting range 23~100A) should be selected.

   - **Environmental Factors**: When the ambient temperature is higher than 40°C, it needs to be used with a derating (for every 10°C increase, the current capacity decreases by 5%).

   - **Expansion Requirements**: If multi-channel signal feedback is required, the **F4-22 auxiliary contact group** can be used to expand it to 4 groups of contacts.

IV. Price and Supplier Information

1. **Market Price Range**

   - **Domestic Channels**:

     - NXR-25 (0.1~25A): ¥120~180

     - NXR-100 (23~100A): ¥350~500

     - NXR-630 (125~630A): ¥1,200~1,800

   - **International Platforms**:

     - Amazon: NXR-25 is approximately $35~50, NXR-100 is approximately $120~150

     - RS Components: NXR-100 is approximately £100~120

2. **Supplier Recommendations**

   - **Domestic Authorized Dealers**:

     - **hebei china Electric**: It covers the whole country and provides technical support and bulk discounts (Whatsapp：0086-13811255435.

   - **International Suppliers**:

     - **Schneider Electric Official Website**: Obtain local authorized dealers through the "Dealer Inquiry" function.

     - **Kempston Controls**: It provides in-stock products and global distribution services.

V. Alternative Models and Compatibility Comparison

VI. Maintenance and Fault Handling

1. **Regular Maintenance**

   - **Clean the Contacts**: Wipe the oxide on the surface of the main contacts with alcohol every quarter to avoid an increase in contact resistance.

   - **Check the Connections**: Tighten the screws to prevent loosening caused by vibration (it is recommended to use a torque wrench, and the torque value for an M4 screw is 1.5N·m).

   - **Test the Protection Function**: Use a **thermal overload relay tester** every year to simulate the overload current and verify whether the tripping time meets the standard.

2. **Common Fault Troubleshooting**

   - **False Tripping**:

     - **Reasons**: The set current is too small, the ambient temperature is too high, and the motor starting time is too long.

     - **Solutions**: Reset the current, improve ventilation, and select a model with a **starting delay function** (such as NXR-100D).

   - **No Tripping**:

     - **Reasons**: The bimetallic strip is fatigued, the contacts are stuck, and the control circuit is disconnected.

     - **Solutions**: Replace the thermal overload relay, check the wiring, and test the control signal.

   - **Abnormal Noise**:

     - **Reasons**: Foreign matter in the iron core or aging of the spring.

     - **Solutions**: Clean the iron core and replace the spring assembly.

VII. Purchasing Suggestions

1. **Give Priority to Authorized Channels**: Confirm the supplier's qualifications through the "Dealer Inquiry" function on the Chint official website to avoid purchasing counterfeit products.

2. **Bulk Purchase Discounts**: For purchases of more than 10 units, you can contact the dealer to negotiate discounts (for example, Nuoyi Electric provides a bulk discount of 10% to 15%).

3. **Alternative Solutions**: If the NXR series is out of stock, you can temporarily replace it with the **Delixi CDZ1-100** (it is necessary to confirm the installation size and current parameters). When purchasing, it is recommended to provide the motor nameplate parameters for accurate selection.