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China CT3 Series Current Transformer - Reliable Power Monitoring Solutions from Trusted Suppliers and Factory

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A current transformer (CT) is a crucial component in electrical systems designed for controlling, monitoring, and protecting power networks. By converting massive alternating currents (AC) into small, measurable levels, CTs play a vital role in power production, transmission, distribution, and various industrial applications. In these high-current power circuits, they are often integrated with safety relays and sensitive measuring devices. Sourced from reputable China suppliers and manufacturers, our current transformers are engineered for reliability and precision, ensuring optimal performance in diverse applications.

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    Product Details

    Product Overview

    A CT operates on electromagnetic induction and has two windings: a primary winding with a few turns linked in series to the high-current circuit, and a secondary winding with many turns connected to safety or measurement devices. The primary winding receives a significant current, whereas the secondary winding, which is normally tuned to 5A or 1A for most industrial applications, receives very little current.

    ⚡

    Transformation Ratio: This proportionality, also known as the transformation ratio, allows for accurate current measurement while safeguarding workers and equipment from potentially hazardous voltages.

    CTs require enough insulation to maintain a high voltage between windings, linearity to minimize measurement error, and high precision for energy metering.

    ⚠️

    Important Warning: When using a CT, never leave the secondary winding open circuit. This is because an open circuit may produce extremely high voltages, which can harm electrical equipment.

    Finally, since they enable more precise current monitoring and improved issue detection, current transformers are crucial to ensuring the reliability, efficiency, and safety of modern electrical systems.

    Technical Parameters

    Type

    Specification

    (mm) Outline Size

    A

    B

    C

    D

    E

    F

    M

    CT3-100

    1 OOA/I OOmA

    118

    60

    30

    108

    18

    20

    c4*7

    CT3-250

    250A/1 OOmA

    136

    64

    35

    123.5

    22

    25

    c4*7

    CT3-400

    400A/1 OOmA

    180

    93

    40

    165.5

    32

    35

    c4*7

    CT3-630

    630A/1 OOmA

    212

    102

    40

    198

    43

    41

    c4*7

    Accuracy Grade: 0.5

    Lead Length: 1 m

    Overload Current: ≥1.2%ln

    Frequently Asked Questions

    ❓ What is a Current Transformer (CT) and how does it work?
    A Current Transformer (CT) operates on the principle of electromagnetic induction. It consists of two windings: a primary winding connected in series with the high-current circuit, and a secondary winding connected to measurement or protection devices. The primary winding carries the large input current, while the secondary winding produces a proportionally smaller output current (typically 5A or 1A), allowing safe and accurate measurement.
    ❓ Why should the secondary winding of a CT never be left open circuit?
    Leaving the secondary winding open circuit is extremely dangerous. When the secondary is open, the magnetic flux in the core is no longer balanced by secondary current, which can generate extremely high voltages across the secondary terminals. This can damage the insulation, destroy the transformer, and pose serious safety hazards to personnel and connected equipment.
    ❓ What accuracy grade do the CT3 series current transformers offer?
    The CT3 series current transformers are rated at Accuracy Grade 0.5, which makes them suitable for precision energy metering and industrial measurement applications. This grade ensures minimal measurement error and reliable performance across the specified current range.
    ❓ What current ratings are available in the CT3 series?
    The CT3 series is available in four current ratings to suit different application requirements: CT3-100 (100A/100mA), CT3-250 (250A/100mA), CT3-400 (400A/100mA), and CT3-630 (630A/100mA). Each model has a corresponding physical size to accommodate the appropriate busbar or conductor dimensions.
    ❓ What is the overload current capability of the CT3 series?
    The CT3 series current transformers support an overload current of ≥1.2% of the rated primary current (ln). This ensures that the transformer can handle temporary current surges without compromising accuracy or causing damage to the device or connected instrumentation.
    ❓ What are the key selection criteria when choosing a CT for an electrical system?
    When selecting a current transformer, consider the following key factors: the rated primary current of the circuit, the required accuracy class for the application (metering vs. protection), the physical dimensions and mounting requirements, the insulation voltage rating, and the burden (load) connected to the secondary winding. For energy metering applications, an accuracy class of 0.5 or better is generally recommended.