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Current Transformers (CT) from China - Reliable Suppliers & Factory for Power Monitoring and Protection

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As one of the leading suppliers of current transformers (CT) in China, our factory produces high-quality electrical devices essential for the safe monitoring, management, and protection of power systems. Current transformers are critical components that convert high alternating currents (AC) into lower, easily detectable levels, ensuring a reliable link between sensitive measuring instruments or protective relays and high-current power circuits. Our products are extensively used in power production, transmission, distribution, and various industrial applications, providing efficiency and safety in electrical operations.

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    Product Details

    Product Overview

    A CT, which uses electromagnetic induction to function, consists of a primary winding (few turns, linked in series with the high-current circuit) and a secondary winding (many turns, connected to safety or measurement devices). While a large current flows through the primary winding, a correspondingly low current flows through the secondary winding, which is typically standardized to 5A or 1A for most industrial applications. This proportionality—also referred to as the transformation ratio—ensures accurate current measurement without exposing personnel or equipment to dangerously high voltages.

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    High Accuracy
    Essential for precise energy metering in industrial applications.
    📈
    Strong Linearity
    Prevents measurement distortion across operating ranges.
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    Insulation Strength
    Maintains high voltage isolation between primary and secondary windings.
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    Important: The secondary winding of a CT should never be open-circuited during operation. An open circuit can result in extraordinarily high voltages that could damage equipment or pose serious safety hazards.

    In conclusion, since they provide precise current monitoring and effective fault protection, current transformers are critical to maintaining the reliability, efficiency, and safety of modern electrical systems.

    Technical Parameters
    Type Rated Current (A) Secondary Current Rated Burden (VA) Class Rated Voltage (V) Rated Frequency (Hz) High Voltage Test Security Factor
    DM-20 50/5A – 400/5A — 1.5 – 5 1.0 / 0.5 720 50 / 60 4KV eff, 50Hz, 1min —
    Frequently Asked Questions
    Q What is the primary function of a current transformer (CT)?
    A current transformer (CT) is designed to measure high currents by stepping them down to a standardized, safer level (typically 5A or 1A) using electromagnetic induction. This allows accurate current monitoring and protection of equipment without direct exposure to high-voltage circuits.
    Q Why should the secondary winding of a CT never be open-circuited during operation?
    If the secondary winding is open-circuited while the primary carries current, all the magnetizing force is used to drive the core into saturation. This generates dangerously high voltages across the secondary terminals, which can damage equipment and pose serious safety risks to personnel.
    Q What does the transformation ratio of a CT mean?
    The transformation ratio refers to the proportional relationship between the primary (high) current and the secondary (low) current. For example, a CT rated 400/5A will reduce 400A in the primary circuit to 5A in the secondary circuit, maintaining proportionality for accurate measurement.
    Q What accuracy classes are available for the DM-20 current transformer?
    The DM-20 current transformer is available in accuracy Class 1.0 and Class 0.5, making it suitable for both general measurement and higher-precision energy metering applications depending on the installation requirements.
    Q What rated voltage and frequency does the DM-20 CT support?
    The DM-20 current transformer supports a rated voltage of 720V and operates at both 50Hz and 60Hz frequencies, making it compatible with a wide range of global electrical systems and industrial environments.
    Q What high voltage test standard does the DM-20 CT comply with?
    The DM-20 current transformer undergoes a high voltage test of 4KV (effective value) at 50Hz for 1 minute. This test verifies the insulation integrity between the primary and secondary windings, ensuring safe and reliable operation under rated conditions.