Inquiry Now
Leave Your Message
Products Categories
Featured Products
SFM118 Series Single Phase Multifunction Meter

SFM118 Series Single Phase Multifunct...
SFM472 Series Three Phase Multifunction Meter

SFM472 Series Three Phase Multifuncti...
Three Phase Digital Combined Meter

Three Phase Digital Combined Meter
Multifunctional watch LED

Multifunctional watch LED
Three Phase Digital Voltmeter, Ammeter

Three Phase Digital Voltmeter, Ammeter
SFN-9K6-3UI Digital Combined Meter

SFN-9K6-3UI Digital Combined Meter
Single Phase Multifunctional Power Instrument

Single Phase Multifunctional Power In...
Single Phase Digital Combined Meter

Single Phase Digital Combined Meter
Power factor meter

Power factor meter
Single-phase meter

Single-phase meter
0102030405
DM-1 transformer distributor .jpg

China Current Transformer (CT) Suppliers - High-Quality Factory Solutions for Power System Monitoring

,

For safe monitoring, management, and protection of power systems, a current transformer (CT) is an essential electrical device that converts high alternating currents (AC) into lower, detectable levels. Acting as a vital link between sensitive measuring devices or protective relays and high-current power circuits, current transformers are extensively utilized in power production, transmission, distribution, and various industrial applications. As a leading supplier and factory in China, we ensure our current transformers meet the highest quality standards, providing reliable and efficient solutions for your power system needs.

,
    Contact us
    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.

    🎯

    High Accuracy

    Necessary for precise energy metering and reliable performance in industrial applications.

    📈

    Strong Linearity

    Prevents measurement distortion, ensuring consistent and trustworthy current readings.

    🛡️

    Insulation Strength

    Maintains high voltage separation between windings to protect equipment and personnel.

    ⚠️

    Important Safety Notice: The secondary winding of a CT should never be open-circuited during operation. An open circuit may result in extraordinarily high voltages that could damage equipment or pose serious safety hazards to personnel.

    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 (FAQ)

    ❓ 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 measuring or protection devices. The CT steps down the high primary current to a standardized, safe secondary current — typically 5A or 1A — proportional to the primary, enabling safe and accurate measurement.
    ❓ Why should the secondary winding of a CT never be left open-circuited?
    If the secondary winding of a CT is open-circuited while current flows through the primary, the transformer will attempt to drive all the magnetomotive force through the core without a load to dissipate it. This results in extremely high voltages across the secondary terminals, which can destroy insulation, damage equipment, and create serious safety risks for personnel.
    ❓ 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 with a ratio of 400/5A will produce a secondary current of 5A when 400A flows through the primary. This ratio ensures accurate, scalable current measurement across a wide range of applications.
    ❓ What are the key technical specifications of the DM-20 current transformer?
    The DM-20 current transformer supports a rated primary current range of 50/5A to 400/5A, a rated burden of 1.5–5 VA, accuracy classes of 1.0 and 0.5, a rated voltage of 720V, and operates at both 50Hz and 60Hz frequencies. Its high voltage test rating is 4KV eff at 50Hz for 1 minute, ensuring robust insulation performance.
    ❓ What accuracy classes are available for this CT, and why does accuracy matter?
    The DM-20 CT is available in accuracy classes 1.0 and 0.5. Accuracy class is critical because it determines the permissible measurement error — a Class 0.5 CT introduces no more than 0.5% error, making it suitable for precise energy metering and billing purposes. Higher accuracy reduces discrepancies in power consumption records and ensures reliable system protection.
    ❓ In what applications are current transformers like the DM-20 commonly used?
    Current transformers such as the DM-20 are widely used in power distribution systems, energy metering panels, industrial switchgear, relay protection circuits, and building management systems. They enable safe monitoring of high currents, support accurate billing, and play a vital role in fault detection and system protection across commercial and industrial electrical installations.