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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 switching device designed for safe and reliable operation in indoor environments. This high-performance circuit breaker is capable of closing, carrying, and breaking current under standard circuit conditions, as well as handling specified over-current within defined time limits. It effectively manages current under abnormal conditions, including various short-circuit scenarios. Ideal for three-phase AC 50/60Hz power systems at 12KV, the VTD9-12D serves as a crucial control and protection unit for electrical systems in industrial and mining enterprises, photovoltaic and wind power applications, residential areas, and urban complexes. As a trusted China supplier and factory, we ensure high-quality manufacturing standards for all our products.

    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:
    product description01
    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

    product description02
    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)
    product description03
    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)

    What are the main applications of the VTD9 vacuum circuit breaker?
    Due to its vacuum technology, it is highly suitable for frequent operations requiring rated working current, or environments where short-circuit currents are broken multiple times. Its compact side-mounted structure makes it ideal for confined spaces like distribution rooms, prefabricated substations, and underground garages.
    Which standards does this vacuum circuit breaker comply with?
    This product fully complies with international and national standards, including IEC62271-1, IEC62271-100, GB1984, GB/T11022, DL/T402, and JB/T3855.
    What are the environmental limits for normal service conditions?
    The standard operating environment requires an ambient temperature of -25℃ to +40℃, an altitude of ≤ 1000m, daily average relative humidity ≤ 95%, monthly average relative humidity ≤ 90%, and a seismic intensity of ≤ 8. The location must be free from dripping water, flammable/explosive hazards, and chemical corrosive gases.
    How does the miniaturization design benefit users?
    With a cabinet width of only 500 mm, it has a significantly smaller volume compared to standard air-insulated switches of the same specification. This allows for highly space-efficient switchgear layouts.
    Does this equipment require frequent maintenance?
    No, the device utilizes maintenance-free vacuum poles (arc extinguishing chambers) which offer a long operational lifetime and very low maintenance requirements, substantially lowering overall operating costs.
    Can the VTD9 and VTD9-12D circuit breakers be installed in reverse?
    Yes, while the outline dimension drawings illustrate normal installation setups, the configuration can also be reversed depending on your installation requirements.

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