Chint Thermal Overload Relay NR2-25/7-10A

Chint Thermal Overload Relay NR2-257-10A is a product in the NR2 series, mainly used for overload and phase-failure protection of AC motors.

1. Technical Parameters and Functional CharacteristicsChint サーマルリレー JR36-63/28A-45A
2. 基本パラメータ

定格電流範囲: 7-10あ, suitable for motor protection where the setting current falls within this range.

フレーム電流: 25あ, which belongs to the medium current specification in the NR2 series and is compatible with contactor models such as NC1/CJX2-09-32.

電圧範囲: Supports AC circuits with 50Hz/60Hz frequency and voltage up to 690V, complying with international and Chinese standards including IEC 60947-4-1 および GB/T 14048.4.

Trip Class: 10あ, with an operating time that meets industry standards to ensure rapid circuit interruption in case of overload.

2. コア機能

過負荷保護: Monitors current through a bimetallic strip structure and triggers tripping when the current exceeds the setting range.

Phase-Failure Protection: Can detect the disconnection of any phase in a three-phase circuit and act within 2 時間.

Temperature Compensation: Adapts to ambient temperatures ranging from -5°C to +40°C, ensuring stability under different working conditions.

Reset Method: Supports both manual and automatic reset; the circuit can be restored by operating the button.

3. 構造設計

設置方法: Can be installed in combination with contactors (例えば, NC1/CJX2 series) or fixed via an independent mounting base (例えば, MB-2).

Wiring Specification: The main circuit supports 1-2.5mm² wires, and the auxiliary circuit uses M3.5 screws, which are suitable for common industrial wiring requirements.

ステータス表示: After tripping, the trip status is displayed through a mechanical indicator window, facilitating quick fault diagnosis.

1. Application Scenarios and Selection Recommendations
2. 代表的な用途

Industrial Motor Control: Suitable for motor protection of equipment such as machine tools, パンプス, そしてファン, especially for loads that require frequent starting and stopping.

Automation Systems: Can be combined with contactors and circuit breakers to form a complete motor control circuit, improving system reliability.

Civil Equipment: Applicable to scenarios with high overload protection requirements, such as elevators and air-conditioning compressors.

2. Selection Notes

現在のマッチング: The setting range should be selected based on the rated current of the motor. 例えば, a 7.5kW three-phase motor (approximately 15A) requires a larger-sized thermal overload relay (例えば, NR2-36).

環境適応力: In high-temperature environments (such as boiler rooms), priority should be given to models with temperature compensation to avoid false tripping.

認定要件: When exporting to the North American market, 製品がUL認証に合格しているかどうかを確認する必要がある (some Chint models have obtained UL certification, but the specific certification status of NR2-257-10A needs further verification).

Ⅲ. Installation and Maintenance Guidelines

1. インストール手順

Combination Installation: Insert directly into the thermal overload relay slot of the contactor and ensure the buckle is firmly locked.

Independent Installation: Fix on the guide rail using the MB-2 mounting base, tighten the M4 screws, and pay attention to maintaining levelness.

Wiring Standards: Connect the main circuit to L1/L2/L3 according to the phase sequence, and connect the auxiliary contacts (いいえ/いいえ) to the control circuit. Ensure the terminal torque meets the standard (reference value: 2.5N・m).

2. Commissioning Key Points

Setting Current Configuration: Rotate the adjustment knob to align the scale with 1.05 モーターの定格電流の倍 (例えば, set to 10.5A for a 10A motor).

機能テスト: Press the test button to simulate an overload, observe whether tripping occurs within 2 分, and verify the effectiveness of the protection function.

3. メンテナンスに関する推奨事項

定期点検: Clean the dust on the housing quarterly, check if the wiring terminals are loose, and test the flexibility of the reset button.

Fault Diagnosis: トリップが頻繁に起こる場合, check whether the motor is overloaded, the wiring is loose, or the setting value of the thermal overload relay is too low.

1. Alternative Models and Purchasing Channels
2. 代替ソリューション

Same-Series Upgrade: If higher current capacity is required, models such as NR2-36 (setting range 28-36A) or NR2-93 (30-40あ) can be selected.

Cross-Brand Compatibility: Siemens 3UA59 and ABB T-series thermal overload relays can be used as alternatives, but attention should be paid to differences in installation dimensions and wiring methods.

2. Procurement Information

価格帯: 単価はおよそ 22-26 人民元. まとめ買いの場合, discounts can be obtained through channels such as 1688 and JD.com, or via WhatsApp: 0086-13811255435.

Certified Versions: Some e-commerce platforms provide export models with CE certification; specific requirements should be specified when placing an order.

1. Precautions and Compliance
2. Safety Standards

接地要件: The metal housing must be reliably grounded (PE), and the grounding resistance should be less than 4Ω.

Isolation Operation: Before replacing the thermal overload relay, be sure to cut off the upper-level power supply and test for electricity to avoid electric shock risks.

2. International Compliance

UL認証: Chint Electric has obtained overall UL certification, but the specific certification status of NR2-257-10A needs to be confirmed by contacting the manufacturer. It is recommended to prioritize models with the UL mark (例えば, NR2-25/Z).

RoHS Directive: The product complies with EU environmental protection requirements and is suitable for equipment exported to Europe.

1. まとめ

With its high cost-effectiveness and stable performance, NR2-257-10A is widely used in small and medium-sized motor protection scenarios. When selecting the model, users should focus on current matching, 環境適応力, and certification requirements. インストール中, wiring standards must be strictly followed, and regular maintenance should be conducted to ensure long-term reliable operation. さらなる技術サポートについては, detailed manuals and after-sales services can be obtained through the Chint official website or customer service channels.