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China CTF2 Series Current Transformer - Quality Power Monitoring Solutions from Leading Suppliers and Factory

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A current transformer (CT) is essential electrical equipment used for controlling, monitoring, and safeguarding power supply systems. It efficiently generates small, measurable quantities of large alternating current (AC), making it crucial for various applications, including power generation, transmission, and distribution. In industrial settings, high-current power circuits often integrate CTs with safety relays or sensitive measuring devices. As a leading supplier in China, our factory produces high-quality current transformers that meet international standards, ensuring optimal performance and reliability for all your electrical needs.

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    Product Details

    Product Overview

    A CT uses electromagnetic induction and is made up of two windings: a secondary winding with several turns connected to safety or measurement devices, and a primary winding with a few turns connected in series to a high-current circuit. The primary winding receives a lot of current, whereas the secondary winding, which is typically tuned to 5A or 1A for the majority of industrial applications, receives very little. This proportionality, sometimes referred to as the transformation ratio, permits precise current monitoring while shielding personnel and equipment from dangerous voltages.

    ⚡ High Precision Energy Metering
    📐 Excellent Linearity & Low Measurement Error
    🛡️ High Voltage Insulation Between Windings
    🔍 Reliable Current Monitoring & Fault Detection

    CTs require high precision for energy metering, linearity to reduce measurement errors, and enough insulation to maintain a high voltage between windings. Finally, since they allow for more exact current monitoring and issue detection, current transformers are critical to the dependability, efficiency, and safety of contemporary electrical systems.

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    Important: Never leave the secondary winding open circuit when using a CT. An open circuit can generate extremely high voltages, which may seriously damage electrical equipment and endanger personnel.

    Technical Parameters

    Type Specification (mm) Outline Size
    A B C D E F M
    CTF2-1025 100A/5A 162 71 28 155 100 25 c5*7
    CTF2-1435 250A/5A 202 81 28 195 140 35 c5*7
    CTF2-1835 400A/5A 242 82 28 235 180 35 c5*7
    CTF2-2245 630A/5A 282 92 28 275 220 45 c5*7
    CTF2-3045 1250A/5A 363 92 28 355 300 45 c5*7
    Accuracy Grade: 1.0 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 a primary winding connected in series with a high-current circuit and a secondary winding connected to measurement or protection devices. The primary winding carries the large line current, while the secondary winding outputs a proportionally reduced current — typically 5A or 1A — safe for metering instruments and relays.
    ❓ Why should the secondary winding of a CT never be left open circuit?
    When the secondary winding is left open circuit, all the primary magnetizing current is used to drive the core into saturation, producing an extremely high and dangerous voltage across the secondary terminals. This can damage insulation, destroy connected equipment, and pose a serious safety risk to personnel. Always ensure the secondary is connected to a load or short-circuited when not in use.
    ❓ What does the transformation ratio of a CT mean?
    The transformation ratio refers to the proportional relationship between the primary current and the secondary current. For example, a CT rated 400A/5A means that when 400A flows through the primary winding, the secondary winding outputs 5A. This ratio allows accurate monitoring of high currents using standard low-range measuring instruments.
    ❓ What accuracy grade do these CTs meet, and why does accuracy matter?
    These current transformers meet Accuracy Grade 1.0, which means the ratio error is within ±1.0% under rated conditions. High accuracy is essential for energy metering applications to ensure billing accuracy, compliance with standards, and reliable protection relay operation. Lower accuracy grades may lead to significant measurement errors over time.
    ❓ What is the overload current rating for these CTs?
    The overload current rating for these CTs is ≥1.2% of the rated primary current (ln). This means the CT can handle short-term overloads of at least 120% of its rated current without significant degradation in performance or damage to the core and windings, ensuring durability in demanding industrial environments.
    ❓ Which CTF2 model should I choose for my application?
    Selection depends on the rated primary current of your circuit. For example, choose CTF2-1025 for systems up to 100A, CTF2-1435 for up to 250A, CTF2-1835 for up to 400A, CTF2-2245 for up to 630A, and CTF2-3045 for up to 1250A. Always ensure the CT's physical outline dimensions (A through M) are compatible with your installation space and busbar size.