Chint CJX2-6511+NR2-93

Technical File of Chint CJX2-6511 + NR2-93

Chint CJX2-6511 + NR2-93 is a standard electromagnetic starter combination, consisting of a CJX2-6511 AC contactor and an NR2-93 thermal overload relay. It is mainly used for remote control, overload and phase failure protection of AC motors, and is widely applied in industrial automation and electrical control systems.

1. Model Interpretation

1. コア技術パラメータ
2. CJX2-6511 AC Contactor

2. NR2-93 Thermal Overload Relay

Ⅲ. 機能的な特徴

1. Features of CJX2-6511 Contactor

High-performance Contacts: Silver alloy contacts with excellent conductivity, strong arc erosion resistance and long service life.

Low-noise Design: Optimized electromagnetic system to reduce noise during pull-in and release.

Modular Structure: Expandable auxiliary contacts for flexible installation.

Safe and Reliable: Complies with GB/T 14048.4 and IEC/EN 60947-4-1 standards, with short-circuit protection coordination capability.

Wide Voltage Adaptability: Control coil is compatible with multiple voltage levels to meet the requirements of different control circuits.

2. Features of NR2-93 Thermal Overload Relay

Comprehensive Protection: Provides both overload and phase failure protection to prevent motor burnout due to phase loss operation.

Temperature Compensation: Maintains stable protection characteristics when ambient temperature changes.

Action Indication: Clear trip status indication for easy fault troubleshooting.

Flexible Reset: Manual/automatic reset selection to adapt to different control requirements.

Plug-in Mounting: Perfectly matched with CJX2 contactor for quick installation and space saving.

3. Advantages of the Combined System

Integrated Control and Protection: The contactor is responsible for circuit on/off and motor starting, while the thermal overload relay provides overload/phase failure protection, forming a complete control and protection unit.

Standardized Design: Complies with international standards and can be seamlessly integrated with other electrical components.

Easy Maintenance: Modular structure allows easy component replacement and reduces maintenance costs.

1. Application Scope
2. Motor Control: Suitable for frequent starting, stopping, forward and reverse rotation control of three-phase AC motors with power below 30kW (380V).
3. Industrial Equipment: General machinery such as fans, ウォーターポンプ, compressors, conveyors and machine tools.
4. Building Electrical Engineering: Central air conditioning systems, fire pumps and elevator control systems.
5. Other Applications: Long-distance controlled power transmission and distribution systems, and electrical circuits requiring overload protection.
6. Selection Recommendations
7. Basic Selection Principles

Contactor Selection: The rated current of main contacts shall be ≥ 1.2-1.5 times the rated current of the motor (inductive load).

Thermal Relay Selection: The adjustable current range shall cover the rated current of the motor (usually set to 0.95-1.05 times the rated current of the motor).

Coil Voltage: Selected according to the power supply of the control circuit, 220V or 380V AC are commonly used.

2. Motor Power Matching Table (380V)

3. Installation and Usage Precautions

Mounting Direction: The contactor and thermal overload relay can be installed horizontally or vertically, with an inclination angle not exceeding 5°.

Wiring Specifications: The terminals of the main circuit shall be tightened to avoid heating; the cross-sectional area of the control circuit wire shall be ≥ 1.5mm².

環境要件: Avoid installation in humid, dusty or corrosive gas environments; altitude ≤ 2000m.

Protection Coordination: Must be used with circuit breakers to provide short-circuit protection.

1. トラブルシューティング

Ⅶ. Substitution and Compatibility

VIII. まとめ

Chint CJX2-6511 + NR2-93 is a cost-effective and highly reliable motor control and protection solution, especially suitable for frequent starting and protection applications of small and medium-sized motors. Its modular design, standardized interface and comprehensive protection functions make it an ideal choice in the field of industrial automation. During selection, it is necessary to choose the appropriate adjustable current specification of the thermal overload relay and the coil voltage of the contactor according to the motor power, rated current and control requirements.

Service Life Details of Chint CJX2-6511 + NR2-93

The service life of the Chint CJX2-6511 + NR2-93 combination shall be comprehensively evaluated from three dimensions: mechanical life (no-load operation times), electrical life (on-load operation times) and actual service life, which is also affected by various factors such as operating conditions and maintenance level.

1. Officially Nominal Life Parameters
2. CJX2-6511 AC Contactor

2. NR2-93 Thermal Overload Relay

1. Key Factors Affecting Service Life
2. Factors Affecting Contactor Life

2. Factor	Influence Mechanism	Influence Degree
   Operating Frequency	Frequent operation accelerates mechanical wear and contact ablation	High (if the frequency is doubled, the life may be halved)
   負荷の種類	The life of AC-4 load (frequent starting/reversing) is 60-80% lower than that of AC-3 load	High
   Voltage Fluctuation	Overvoltage causes coil overheating, and undervoltage causes contact bouncing	Medium-High
   環境条件	Temperature > 40℃, humidity, dust and corrosive gas accelerate aging	Medium
   Mounting Method	Non-vertical installation (inclination > 5°) affects heat dissipation and mechanical action	Low
   Maintenance Level	Regular cleaning and terminal tightening can extend the service life	Medium

   Factors Affecting Thermal Overload Relay Life

Ⅲ. Life Estimation in Practical Application

1. Calculation of Actual Contactor Life (例)

Assumed working conditions: AC-3 utilization category, 100 operations per day, 300 working days per year

Theoretical electrical life: 600,000 operations

Annual operation times: 100 operations/day × 300 days = 30,000 operations/year

Expected service life: 600,000 ÷ 30,000 = 20 years (ideal working conditions)

If it is AC-4 utilization category with 200 operations per day:

Theoretical electrical life: 100,000 operations

Annual operation times: 200 × 300 = 60,000 operations/year

Expected service life: 100,000 ÷ 60,000 = about 1.7 years (severe working conditions)

2. Estimation of Actual Thermal Overload Relay Life

Control Contact Life: With 50 operations per day, the theoretical 100,000 operations can last for about 5.5 years.

Heating Element Life: Under normal use (less than 5 overload trips per month), it can work stably for 8-10 years.

Overall Life: Usually determined by the life of the contactor; the thermal overload relay can be replaced as a wearing part.

1. Practical Suggestions for Extending Service Life
2. Selection Optimization

The rated current of the contactor shall be ≥ 1.2-1.5 times the rated current of the motor.

For frequent starting/reversing conditions, select AC-4 dedicated contactors or use them with derating.

2. Installation and Usage Specifications

Install vertically with good ventilation; control the ambient temperature within -5℃ ~ +40℃.

Keep the control coil voltage stable within ±10% of the rated value.

Set the adjustable current of the thermal overload relay to 0.95-1.05 times the rated current of the motor.

3. Maintenance Measures

Regularly clean the contacts and iron core to remove dust and oil stains.

Check the wiring terminals to prevent loosening and heating.

After 3-5 years of operation of the contactor, the contacts and coil can be replaced.

When the thermal overload relay trips frequently, check the motor load and main circuit.

1. まとめ

Under standard working conditions (AC-3, 100 operations per day), the electrical life of the contactor in the Chint CJX2-6511 + NR2-93 combination is about 20 years, and the mechanical life far exceeds the actual service demand; the overall life of the thermal overload relay is about 10 years. The actual service life mainly depends on the operating frequency, load type and maintenance level, and may be shortened to 1-2 years under severe working conditions. Through reasonable selection, standardized use and regular maintenance, the service life of the equipment can be effectively extended and the replacement cost can be reduced.