Chint NKB8-32/8A-32A/AC220VControl and Protective Switching Device (CPS)

Chint NKB8-32/8A-32A/AC220V is a **Control and Protective Switching Device (CPS)** that integrates the functions of a contactor, circuit breaker, and motor protector. It is specifically designed for power systems with an AC frequency of 50Hz and a rated voltage up to 690V, and is particularly suitable for the control and protection of 3~15kW motors. The following is its core information and application guidelines:

 I. Core Functions and Technical Parameters

1. **Protection Module (CTU-1D32D)*Chint NXR series thermal overload relays price**  

   - **Overload protection**: The setting range is 8~32A (corresponding to 3~15kW motors with 400V/AC-43 loads), supporting the adjustment of inverse time curves to avoid frequent misoperations.  

   - **Short-circuit instantaneous protection**: Instantaneous tripping at 16 times the rated current (16Ie) with a response time of <0.1 seconds, and the breaking capacity reaches 50kA (400V).  

   - **Intelligent protection functions*CHINT circuit breaker price*:  

     - Phase loss protection: Triggers tripping within 5 seconds (default value) when a phase loss is detected.  

     - Three-phase imbalance protection: The threshold can be set (10%~100%), and it acts within 10 seconds when the default imbalance degree of 35% is reached.  

     - Locked rotor/blocking protection: Locked rotor protection is for the starting process (5~9Ie, 2-second delay), and blocking protection is for abnormalities during operation (5~9Ie, 2-second delay).  

     - Under-current/under-voltage protection: The under-current protection can be set to 20%~80% of the rated current (80% by default), and the under-voltage protection is 70%~90% of the rated voltage (80% by default).  

2. **Power Base Module (PBU1T32)*CHINT contactor price*  

   - **Rated current**: 32A, suitable for 3~15kW motors under 400V/AC-43 working conditions.  

   - **Control power supply**: AC220V is directly controlled through A1/A2 terminals, or independently powered through A3/A4 terminals.  

   - **Breaking capacity**: The short-circuit breaking capacity under AC-43 working conditions is 50kA, meeting industrial-grade requirements.  

3. **Modular Design*CHINT surge protector price*  

   - Adopts a split structure, with the transformer module and main control unit installed separately, supporting 35mm guide rail or screw fixation, saving space in the control cabinet.  

   - Expandable communication functions (such as ModBus-RTU protocol) to realize remote monitoring.  

 II. Installation and Operation

1. **Wiring Specifications**  

   - **Main circuit**: The terminal blocks are suitable for 4~16mm² wires, with L1/L2/L3 as the incoming ends and T1/T2/T3 as the outgoing ends.  

   - **Control circuit**: Use 0.75~1.5mm² wires, A1/A2 are connected to the AC220V control power supply, and A3/A4 can be optionally equipped with independent power supply.  

   - **Grounding requirements**: Ensure reliable grounding, with a grounding resistance ≤4Ω.  

2. **Parameter Setting**  

   - Enter the menu through the panel buttons (Ent/∧/∨/Esc) to adjust parameters such as overload current and delay time. For example, set the overload protection current to 1.1 times the rated current of the motor, and the delay time matches the starting characteristics of the load.  

   - Supports manual reset (panel buttons) and remote reset (external signal input), and automatically locks the current value after a fault for analysis.  

3. **Status Monitoring**  

   - **LED indicators**:(visually display the status of power supply, operation, overload, voltage, etc.).  

   - **Data display**: Cyclically display the average value of three-phase current and the real-time current of A/B/C phases, with an error of <±2%.  

 III. Application Scenarios and Selection Suggestions

1. **Typical Applications**  

   - **Industrial field**: Protection of three-phase asynchronous motors such as fans, water pumps, and cranes, especially suitable for loads with frequent starting (such as conveyor belts).  

   - **Commercial buildings**: Energy saving and protection of air conditioning compressors and elevator motors, which can be connected to the building automation system through communication interfaces.  

   - **Alternative solution**: Replace the traditional thermal relay + contactor combination, reducing cabinet space and improving protection accuracy.  

2. **Selection Points**  

   - **Power matching**: Select the corresponding model according to the rated current of the motor. CTU-1D32D is suitable for 3~15kW (400V) motors to avoid reduced protection sensitivity due to over-selection.  

   - **Environmental adaptability**: A heat dissipation module is required for high-temperature environments (>50℃), and a cabinet with IP54 protection level is recommended for high-humidity environments.  

   - **Certification requirements**: For export to the North American market, it is necessary to confirm whether it has passed UL certification (you can contact Chint customer service for the latest certification information).  

IV. Maintenance and Troubleshooting

1. **Daily Maintenance**  

   - Clean the housing and terminal blocks quarterly, and check whether the terminals are loose.  

   - Use a multimeter to detect whether the voltage of the control circuit is stable (AC220V±10%) to avoid misoperation caused by voltage fluctuations.  

2. **Common Fault Troubleshooting**  

   - **False tripping**: Check if the load is overloaded for a short time, or adjust the inverse time curve to extend the action time.  

   - **No display**: Confirm whether the control power supply is normal, and check the voltage of A1/A2 terminals and whether the fuse is blown.  

   - **Communication interruption**: Check if the RS485 wiring is correct and whether the baud rate setting is consistent with the upper computer.  

3. **Official Support**  

   - Users in North America can purchase through local distributors or obtain customized solutions via Whatsapp: 0086-13811255435.  

V. Compliance and Certification

- **Domestic standards**: Complies with GB14048.9 "Low-voltage switchgear and controlgear" and has passed CQC certification.  

- **International certification**: It is recommended that export users confirm the certification requirements of the target market in advance (such as UL, CE), and can apply for customized certification versions through Chint's official channels.  

**Summary**: With its integrated design, high-precision protection, and flexible configuration, NKB8-32/8A-32A/AC220V has become the preferred solution for motor control and protection in industrial and commercial fields. When selecting and using, a comprehensive evaluation should be made in combination with load characteristics, environmental conditions, and certification requirements to achieve the best protection effect.  

Chint CTU1-32 motor protector is the core component of the NKB8 series control and protection switching devices, specially providing comprehensive protection for motors. The following is its key information and application guidelines:

 I. Core Functions and Technical Parameters

1. **Protection Functions**  

   - **Overload protection**: Supports definite time and inverse time actions, with the overload current setting range of 3~12A (corresponding to 1.1~5.5kW motors with 400V/AC-43 loads). The inverse time curve can be adjusted according to load characteristics to avoid frequent misoperations.  

   - **Short-circuit instantaneous protection**: Instantaneous tripping at 16 times the rated current (16Ie) with a response time of <0.1 seconds, effectively preventing the expansion of short-circuit faults.  

   - **Phase loss/open-phase protection**: Triggers tripping within 5 seconds (default value) after detecting a power failure in any phase, avoiding motor burnout due to phase loss.  

   - **Three-phase imbalance protection**: The imbalance threshold can be set (10%~100%), and it acts within 10 seconds when the default imbalance degree of 35% is reached.  

   - **Locked rotor/blocking protection**: Locked rotor protection is for the starting process (5~9 times the rated current, 2-second delay), and blocking protection is for abnormalities during operation (5~9 times the rated current, 2-second delay).  

   - **Under-current/under-voltage protection**: The under-current protection can be set to 20%~80% of the rated current (80% by default), and the under-voltage protection is 70%~90% of the rated voltage (80% by default).  

2. **Electrical Parameters**  

   - **Rated current**: 32A, suitable for 3~15kW motors under 400V/AC-43 working conditions.  

   - **Breaking capacity**: The short-circuit breaking capacity under AC-43 working conditions reaches 50kA (400V), meeting industrial-grade short-circuit protection requirements.  

   - **Control power supply**: Powered by AC220V, which can be directly controlled through A1/A2 terminals or independently powered through A3/A4 terminals.  

3. **Modular Design**  

   - Adopts a split structure, with the transformer module and main control unit installed separately, supporting 35mm guide rail or screw fixation, saving space in the control cabinet.  

   - Expandable communication functions (such as ModBus-RTU protocol) to realize remote monitoring and data collection.  

 II. Installation and Operation

1. **Installation Requirements**  

   - **Environmental conditions**: Operating temperature -30℃~70℃, humidity <90%, avoiding strong electromagnetic interference and corrosive gases.  

   - **Wiring specifications**: The main circuit terminals are suitable for 4~16mm² wires, and the control circuit uses 0.75~1.5mm² wires, ensuring reliable grounding.  

   - **Installation method**: The transformer module is directly connected in series to the main circuit of the motor, and the main control unit is fixed on the control cabinet panel through a buckle, supporting embedded or rail installation.  

2. **Parameter Setting**  

   - Enter the menu through the panel buttons (Ent/∧/∨/Esc) to adjust parameters such as overload current, delay time, and protection threshold. For example, set the overload protection current to 1.1 times the rated current of the motor, and the delay time matches the starting characteristics of the load.  

   - Supports manual reset (panel buttons) and remote reset (external signal input), and automatically locks the current value after a fault for analysis.  

3. **Status Monitoring**  

   - **LED indicators**: The status of power supply, operation, overload, voltage, etc., is visually displayed through different color LEDs.  

   - **Data display**: Cyclically display the average value of three-phase current and the real-time current of A/B/C phases, with an error of <±2%.  

 III. Application Scenarios and Selection Suggestions

1. **Typical Applications**  

   - **Industrial equipment**: Protection of three-phase asynchronous motors such as fans, water pumps, and cranes, especially suitable for loads with frequent starting (such as conveyor belts).  

   - **Commercial buildings**: Energy saving and protection of air conditioning compressors and elevator motors, which can be connected to the building automation system through communication interfaces.  

   - **Alternative solution**: Can replace the traditional thermal relay + contactor combination, reducing cabinet space and improving protection accuracy.  

2. **Selection Points**  

   - **Power matching**: Select the corresponding model according to the rated current of the motor. CTU1-32 is suitable for 3~15kW (400V) motors to avoid reduced protection sensitivity due to over-selection.  

   - **Environmental adaptability**: A heat dissipation module is required for high-temperature environments (>50℃), and a cabinet with IP54 protection level is recommended for high-humidity environments.  

   - **Certification requirements**: For export to the North American market, it is necessary to confirm whether it has passed UL certification (you can contact Chint customer service for the latest certification information).  

IV. Maintenance and Troubleshooting

1. **Daily Maintenance**  

   - Clean the housing and terminal blocks quarterly, and check whether the terminals are loose.  

   - Use a multimeter to detect whether the voltage of the control circuit is stable (AC220V±10%) to avoid misoperation caused by voltage fluctuations.  

2. **Common Fault Troubleshooting**  

   - **False tripping**: Check if the load is overloaded for a short time, or adjust the inverse time curve to extend the action time.  

   - **No display**: Confirm whether the control power supply is normal, and check the voltage of A1/A2 terminals and whether the fuse is blown.  

   - **Communication interruption**: Check if the RS485 wiring is correct and whether the baud rate setting is consistent with the upper computer.  

3. **Official Support**  

   - Users in North America can obtain customized solutions via Whatsapp: 0086-13811255435.  

V. Compliance and Certification

- **Domestic standards**: Complies with GB14048.9 "Low-voltage switchgear and controlgear" and has passed CQC certification.  

- **International certification**: It is recommended that export users confirm the certification requirements of the target market in advance (such as UL, CE), and can apply for customized certification versions through Chint's official channels.  

**Summary**: With its modular design, high-precision protection, and flexible configuration, the CTU1-32 motor protector has become the preferred solution for motor protection in industrial and commercial fields. When selecting and using, a comprehensive evaluation should be made in combination with load characteristics, environmental conditions, and certification requirements to achieve the best protection effect.