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DM-1 transformer distributor .jpg

China Current Transformer DM Series - Reliable Power Monitoring Solutions from Top Suppliers & Factory

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Discover the importance of current transformers (CTs) in ensuring the safe monitoring, management, and protection of power systems. These essential electrical devices convert high alternating currents (AC) into lower, easily detectable values, making them indispensable in various applications. Acting as a vital link between sensitive measuring instruments or protective relays and high-current power circuits, these CTs are widely utilized across power production, transmission, distribution, and industrial sectors. As a leading factory and supplier in China, we pride ourselves on providing high-quality current transformers designed to meet the rigorous demands of modern power systems.

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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 and monitoring.

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    Strong Linearity

    Prevents measurement distortion across the full range.

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    Insulation Strength

    Maintains high voltage isolation between windings.

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    Important Warning: The secondary winding of a CT should never be open-circuited during operation. An open circuit can result in extraordinarily high voltages that could seriously damage equipment or pose a safety hazard to personnel.

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

    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 4KVeff, 50Hz, 1min —

    Frequently Asked Questions (FAQ)

    Q What is a Current Transformer (CT) and how does it work?
    A Current Transformer (CT) operates on the principle of electromagnetic induction. It steps down high primary currents to a lower, standardized secondary current (typically 1A or 5A), allowing safe measurement and monitoring of large currents in electrical systems.
    Q 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 400/5A will reduce a 400A primary current to a 5A secondary output, enabling safe and accurate measurement.
    Q Why should the secondary winding of a CT never be open-circuited?
    If the secondary winding is open-circuited while the primary is energized, the entire magnetic flux will attempt to generate voltage in the secondary, resulting in dangerously high voltage levels. This can cause insulation failure, equipment damage, or risk of electric shock to personnel.
    Q What accuracy classes are available for the DM-20 Current Transformer?
    The DM-20 CT is available in accuracy Class 1.0 and Class 0.5. Class 0.5 provides higher precision and is typically used in energy metering applications, while Class 1.0 is suitable for general industrial monitoring purposes.
    Q What is the rated voltage and high voltage test standard for the DM-20?
    The DM-20 has a rated voltage of 720V. Its high voltage test is performed at 4KVeff, 50Hz for 1 minute, ensuring robust insulation performance and reliable operation in demanding electrical environments.
    Q In what applications are current transformers most commonly used?
    Current transformers are widely used in energy metering, power monitoring systems, overcurrent and fault protection relays, and industrial electrical panels. They enable safe interaction with high-voltage circuits while providing accurate data for system management and protection.