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China VTD9-12D Indoor High Voltage AC Vacuum Circuit Breaker - Reliable Suppliers & Factory Solutions

Product Overview
The VTD9-12D indoor high-voltage AC vacuum circuit breaker is an essential indoor switching device designed to effectively close, carry, and break current under normal operating conditions. It is capable of handling specified over-current within defined durations and managing current interruptions during abnormal circumstances, such as various short-circuit scenarios. This advanced circuit breaker is ideally suited for three-phase AC systems operating at 50/60Hz and 12KV, making it a vital control and protection unit for electrical infrastructure across various sectors, including industrial and mining enterprises, photovoltaic wind power installations, residential areas, and urban complexes. As a leading product from trusted China suppliers and manufacturers, the VTD9-12D combines reliability and performance for effective power management.

    Detail introduction

    Due to the special advantages of vacuum circuit breakers, they are particularly suitable for frequent operations that require a rated working current, or for places where short-circuit currents are broken multiple times. The three poles of this circuit breaker are longitudinally fixed on the side mounted chassis, including isolation switches, circuit breakers, earthing switches, and operating mechanisms, forming a side mounted structure. Due to its characteristics of miniaturization, integration, modularization, low maintenance, and consistent appearance, it is particularly suitable for installation in confined spaces such as distribution rooms, prefabricated substations, underearth garages, etc.

    Quality standard

    Product quality assurance is based on continuous improvement of research, development, design, and production processes that meet all aspects of the quality system requirements. It fully complies with the latest versions or modified versions of the following standards, specifications, and guidelines, and is not limited to them.
    IEC62271-1 High voltage switchgear and control gear - Part 1: Common technical requirements for AC switchgear and control gear
    IEC62271-100 High voltage switchgear and control equipment - Part 100: High voltage AC circuit breakers
    GB1984 AC High Voltage Circuit Breaker
    GB/T11022 Common Technical Requirements for High Voltage Switchgear and Control Equipment Standards
    DL/T402 High Voltage AC Circuit Breaker
    JB/T3855 High voltage AC vacuum circuit breaker

    Service Conditions

    • Environmental temperature: - 25℃ ~ +40℃;
    • Altitude: ≤ 1000m;
    • Relative humidity:
      Daily average relative humidity ≤ 95%
      Monthly average relative humidity ≤ 90%
      Daily average vapor pressure ≤ 2.2x10-3 MPa
      Monthly average vapor pressure ≤1.8x10-3MPa;
    • Seismic grade: seismic intensity ≤ 8;
    • The applicable location is free from dripping water, flammable and explosive hazards, chemical corrosive gases, and severe vibrations.
    ※Note: When the usage environment deviates from normal usage conditions, please consult with our company to determine.

    Technical parameter

    Item Unit Parameter
    Rated frequency Hz 50/60
    Rated voltage kV 12
    Rated power frequency withstand voltage (1 minute, r.m.s) Phase to phase and phase to earth KV 42
    Isolation fracture 48
    Control and auxiliary circuits 2
    Rated lightning impulse withstand voltage (peak) Phase to phase and phase to earth kV 75
    Isolation fracture 85
    Rated current A 630, 1250
    Rated short-circuit breaking current (rm..s) kA 20, 25, 31.5
    Rated short-time withstand current and time kA/s 20/4, 25/4, 31.5/4
    Rated peak withstand current kA 50, 63, 80
    Rated short-circuit making current (peak) kA 50, 63, 80
    Rated breaking current of single/back-to-back capacitor group A 400(630)/400
    Rated capacitor bank making current kA 2.5 ( fre.≤1000Hz)
    Rated handover (transfer) current A /
    Mechanical life Times 10000
    Main circuit resistance of each phase ≤ 80, ≤ 70
    Clearance between open contacts mm 9 ± 1
    Contacting travel mm 5.5 ± 1
    Contact closing bounce time mm ≤2
    Three-phase asynchronous closing and opening ms ≤2
    Average opening speed (contact just opened - 6mm) m/s 0.9 ~1.3
    Average closing speed ( 6mm - contact just opened) m/s 0.4 ~ 0.8
    Rated contact pressure N 2400±200 (20 - 25kA)
    3100±200 (31, 5kA)
    Opening time (at rated voltage) ms ≤ 45
    Closing time (at rated voltage) ms ≤ 70
    Rated operating sequence   O-0.3s-CO-180s-CO

    Technical characteristics

    Reasonable design and novel structure
    The operating mechanism is integrated with the "five-prevention" interlocking mechanism, and modular design is adopted for components such as the (circuit breaker) solid-sealed pole and the earthing switch. These components are combined into a single unit through a common mounting frame. The operating panel indicators are integrated with the primary circuit indicators, providing clear, simple, and easy-to-understand indications. The interlocking design is rationally integrated to form a "foolproof" operating procedure, making incorrect operations "impossible".
    Miniaturization
    Compared with air-insulated switches of the same model and specification, the device has a smaller volume, with a cabinet width of only 500 mm. It is a paragon of the new generation of miniaturized air-insulated switchgear.
    Less maintenance
    The device uses maintenance-free vacuum (arc extinguishing chamber) switch (poles), which are virtually maintenance-free, have a long service life, and offer low operating costs.
    Visual Consistency
    VTD9 circuit breaker, FTD9 load switch, and GTD isolating switch have identical external dimensions, facilitating the expansion and combination of switchgear cabinets.

    Basic structure

    The typical structure of the circuit breaker is shown in the figure below:
    VTD9-12D vacuum circuit breaker basic structure
    VTD9-12D
    1 Upper terminal
    2 Wall-through pole
    3 Isolation switch
    4 Operating mechanism (box)
    5 Cable terminal
    6 Earthing switch
    7 Installation rack
    8 (door opening) Interlocking board
    9 (door closing) Interlocking board
    10 Earthing switch operation (shaft) hole
    11 Earthing switch on/off status indication
    12 Energy storage status indication
    13 Counter
    14 Circuit breaker opening and closing status indication
    15 Energy storage handle
    16 Opening button
    17 Closing button
    18 Isolation switch on/off status indication
    19 App Lock
    20 Isolation switch operation (shaft) hole

    Typical outline dimensions (fit) and structural diagram

    VTD9-12 outline dimension drawing
    Rated current (A) 630 1250
    Rated short-circuit breaking current (kA) 20, 25, 31.5
    Inter-phase distance (mm) 210
    VTD9-12 (inter-phase distance P=210) outline dimension drawing of vacuum circuit breaker
    (this drawing is for normal installation, but it can also be reversed)
    VTD9-12D outline dimension drawing
    Rated current (A) 630 1250
    Rated short-circuit breaking current (kA) 20, 25, 31.5
    Inter-phase distance (mm) 210
    VTD9-12D (inter-phase distance P=210) outline dimension drawing of vacuum circuit breaker
    (this drawing is for normal installation, but it can also be reversed)

    Frequently Asked Questions (FAQ)

    1. What are the ideal installation spaces for this vacuum circuit breaker?
    Due to its miniaturized, integrated, and modular design, it is highly suitable for confined spaces such as distribution rooms, prefabricated substations, and underground garages.
    2. Which international and national quality standards does the product comply with?
    The product fully complies with IEC62271-1, IEC62271-100, GB1984, GB/T11022, DL/T402, and JB/T3855 quality and performance standards.
    3. What are the ambient temperature requirements for normal operation?
    The standard environmental temperature range for operation is -25℃ to +40℃. For conditions outside this range, please consult our technical team.
    4. What is the rated mechanical life of the VTD9-12 series?
    The VTD9-12 series has a rated mechanical life of 10,000 operations, ensuring long-term durability with low maintenance.
    5. Can the outline dimensions installation be reversed?
    Yes, while the structural drawings illustrate the normal installation layout, the system is designed to allow for reversed installation based on project requirements.
    6. What safety features are integrated into the operating mechanism?
    The operating mechanism is integrated with a "five-prevention" interlocking mechanism, creating a foolproof operating procedure that makes incorrect manual operations impossible.

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