Chint Current Transformer BH-0.66 40I

   Chint Current Transformer BH-0.66 40I is a precision measuring device suitable for low-voltage power distribution systems.

 I. Model Meaning and Basic Parameters

- **Model Interpretation**:

  - **BH**: Represents a closed-type current transformer

  - **0.66**: Rated voltage of 0.66kV (660V), suitable for low-voltage power grids

  - **40I**:

    - **40**: Punching size is 40mm, which can accommodate cables or busbars with a diameter ≤ 40mm

    - **I**: Represents Type Ⅰ design, adopting a square-round hole structure, compatible with cable and busbar installation

- **Key Parameters**:

  - **Rated Primary Current**: Covers specifications such as 150/200/250/300/400/500/600A (specifically depending on the suffix mark; for example, 400/5A means 400A for the primary side and 5A for the secondary side)

  - **Secondary Current**: The standard is 5A, complying with the GB/T 20840.1 standard

  - **Accuracy Class**: Supports high-precision measurement such as Class 0.2, Class 0.5, and Class 0.5S, meeting the needs of electric energy metering and monitoring

  - **Rated Load**: 3.75-10VA, ensuring accuracy is maintained under different loads

II. Technical Characteristics and Application Scenarios

1. **Core Functions**:

   - **Precision Measurement**: Adopts a high-magnetic-conductivity silicon steel sheet core, and the secondary winding is uniformly wound to ensure Class 0.2 accuracy

   - **Safety Design**: Fully plastic-enclosed structure, with an insulation level reaching 3kV/min power frequency withstand voltage, complying with the GB 1208 standard

   - **Flexible Installation**: Supports busbar fixing or base plate installation, and the punching design facilitates quick on-site through-core wiring

2. **Typical Applications**:

   - **Electric Power Metering**: In three-phase four-wire power grids of 0.66kV and below, it cooperates with electric energy meters to realize accurate electric energy metering

   - **Industrial Monitoring**: Used for current monitoring of equipment such as motors and frequency converters, supporting PLC or DCS system access

   - **Relay Protection**: Cooperates with relays to realize short-circuit and overload protection, with the Accuracy Limit Factor (ALF) reaching 10-20 times

 III. Selection and Usage Recommendations

1. **Key Selection Points**:

   - **Current Matching**: Select the primary rated value according to the maximum current of the measured line, and it is recommended to leave a 20% margin (for example, a 500/5A model is selected for a 400A line)

   - **Accuracy Requirement**: Class 0.2S is preferred for metering scenarios, and protection classes such as 5P10 can be selected for protection scenarios

   - **Installation Environment**: For indoor use, the ambient temperature ranges from -5℃ to +40℃, and the humidity is ≤ 85%

2. **Wiring Specifications**:

   - **Polarity Marking**: P1 is the primary incoming terminal, and S1 is the secondary homonymous terminal, which must correspond correctly to the electric meter/relay

   - **Grounding Requirement**: The secondary circuit must be reliably grounded to prevent high voltage from intruding and endangering equipment safety

   - **Load Matching**: The total impedance of the secondary circuit should be ≤ the rated load to avoid accuracy degradation

 IV. Certification and International Adaptation

- **Domestic Standards**: Complies with GB 1208 and GB/T 20840.1-2007, and has passed CQC certification

- **International Expansion**:

  - Some models have passed CE certification and can meet the needs of the EU market

 V. Purchase and Technical Support

1. **Procurement Channels**:

   - **International**: Place orders through Chint's global distribution network via WhatsApp: 0086-13811255435, supporting OEM customization

2. **Technical Services**:

   - Provide product manuals, wiring diagrams, and calibration reports, and support the customization of non-standard specifications (such as open-type, large-aperture)

   - After-sales Service Hotline: WhatsApp: 0086-13811255435

 VI. Alternative Solutions and Precautions

- **Alternative Models**:

  - If a higher voltage level is required, the LMK1-0.66 series (supporting 1kV) can be selected

  - For outdoor scenarios, it is recommended to consider the LAJ-10 type epoxy resin cast transformer

- **Usage Taboos**:

  - It is strictly forbidden to operate with the secondary side open, otherwise, an induced voltage of thousands of volts may be generated

  - Transformers of different accuracy classes must not be mixed to avoid metering errors

With its high cost-effectiveness and reliability, this series of products has been widely used in projects such as the rural power grid transformation of the State Grid and industrial plant power distribution. For example, in a 400V three-phase motor control circuit, the BH-0.66 500/5A Class 0.5 transformer is used, which cooperates with a multi-function electric meter to realize real-time current monitoring. The accuracy error is less than 0.3%, which fully meets the requirements of the ISO 50001 energy management system.

 Notes on Technical Terms

- **Current Transformer**: A device that converts large primary current into small secondary current in a certain proportion for measurement or protection purposes, which is the core component of power system measurement and protection.

- **Accuracy Class**: A parameter that indicates the maximum allowable error of the transformer under rated working conditions. The smaller the value, the higher the accuracy (e.g., Class 0.2 means the maximum allowable error is ±0.2%).

- **GB Standards**: Abbreviations of national standards of the People's Republic of China (e.g., GB 1208 is the national standard for current transformers in China), which have important guiding significance for product design, production, and use.

- **CE Certification**: A mandatory safety certification mark within the EU, indicating that the product meets the relevant safety, health, and environmental protection requirements of the EU.