Hyundai HAT 25 3-Pole 2500A Air Circuit Breaker – Heavy-Duty LV Power Protection

The Hyundai HAT 25 Air Circuit Breaker 3-Poles 2500Amp is a heavy-duty low voltage circuit breaker engineered for primary power distribution protection in industrial plants, marine switchboards, offshore platforms, and large commercial facilities. At Aeliya Marine Tech, we offer this fully tested used Hyundai HAT 25 ACB — delivering 2500-ampere interrupting capacity with electronic trip coordination at a fraction of the cost of a new equivalent breaker.

Air circuit breakers (ACBs) in the 2500A class represent the workhorses of low-voltage power distribution. The Hyundai HAT 25 protects main busbars, transformer secondaries, generator outputs, and large motor feeders where molded case circuit breakers (MCCBs) lack the current rating and selective coordination capability required. With a rated operational voltage of 660V AC and an electronic AOR-1S-AS/15 trip unit, this breaker provides adjustable long-time, short-time, instantaneous, and ground fault protection — essential for modern power system selective coordination studies.

Manufactured by Hyundai Heavy Industries Electric, the HAT series ACBs are built to IEC 60947-2 standards and have earned a reputation for reliability in Korea's shipbuilding industry — the world's largest — where they protect main switchboards on LNG carriers, container ships, and offshore drilling rigs. This proven marine pedigree makes the HAT 25 an excellent choice for any demanding electrical environment.

Product Overview: Hyundai HAT 25 Air Circuit Breaker

The Hyundai HAT 25 is a draw-out type air circuit breaker with three poles, rated for continuous currents up to 2500 amperes at voltages up to 660V AC. The breaker employs a stored-energy spring-charged operating mechanism that delivers fast, consistent closing and opening characteristics — critical for clearing high-magnitude fault currents before downstream equipment sustains thermal or mechanical damage.

This particular unit features the AOR-1S-AS/15 electronic trip unit — a microprocessor-based protection relay that provides four independent protective functions: Long-Time Delay (LTD) for overload protection, Short-Time Delay (STD) for selective fault coordination, Instantaneous (INST) for maximum fault clearing speed, and Ground Fault (GF) for personnel and equipment protection against earth faults. Each protection curve is field-adjustable via the trip unit's front panel interface or through a connected communication module.

The breaker is supplied with a 2000A base frame and 2500/5A current transformers, indicating this unit has been uprated from its original 2000A base rating to the full 2500A capability through the installation of higher-ratio CTs and appropriate trip unit configuration. This uprating approach is common practice in switchboard upgrades and demonstrates the modular expandability of the HAT series platform.

The 24V DC control voltage is standard for marine and industrial applications where DC control circuits are preferred for their immunity to AC voltage sags and their compatibility with battery-backed UPS systems.

Technical Specifications

Parameter	Specification
Manufacturer	Hyundai Heavy Industries Electric
Model / Series	HAT 25
Poles	3-Pole (3-Phase)
Rated Current (In)	2500 A
Rated Voltage (Ue)	660 V AC
Frequency	50-60 Hz
Trip Unit	AOR-1S-AS/15 Electronic Trip Unit
Base Frame Rating	2000A (uprated to 2500A with CT change)
Current Transformers	2500/5A CTs (included)
Control Voltage	24V DC
Operating Mechanism	Stored Energy Spring-Charged (Motor/Charging)
Installation Type	Draw-Out (Withdrawable) — Fixed Also Available
Breaking Capacity	Up to 65kA @ 440V AC (ICU), 50kA @ 660V AC
Standard Compliance	IEC 60947-2, EN 60947-2, NEMA AB1 (where applicable)
Protection Functions	Long-Time (L), Short-Time (S), Instantaneous (I), Ground Fault (G)
Condition	Used — Fully Tested

Key Features & Benefits

• 2500A Continuous Current Rating: Handles the full load of large transformer secondaries, main switchboards, and heavy industrial busbars where standard MCCBs top out at 1600A or below.
• AOR-1S-AS/15 Electronic Trip Unit: The microprocessor-based trip unit provides true RMS sensing, four independent protection curves (L-S-I-G), and adjustable time-current settings. Unlike thermal-magnetic trips, electronic units maintain calibration accuracy across temperature extremes and over decades of service life.
• Selective Coordination Capability: The short-time delay (S) function introduces an intentional time delay on high-magnitude faults — allowing downstream breakers to clear local faults while the main breaker remains closed. This selective coordination preserves power to unfaulted portions of the distribution system.
• Draw-Out Construction: The withdrawable design allows the breaker to be racked out for maintenance, testing, or replacement without de-energizing the entire switchboard — a critical safety and availability feature in continuous-process industries.
• 2500/5A Current Transformers Included: The included CTs are properly sized for 2500A metering and protection applications, eliminating the need to source and install separate instrument transformers.
• 24V DC Control Circuit: DC control voltage is the marine and heavy industrial standard, providing immunity from AC voltage sags and seamless integration with battery-backed control systems and emergency power schemes.
• Spring-Charged Stored Energy Mechanism: The motor-charged spring mechanism delivers consistent closing speed independent of operator technique — ensuring reliable make/break performance under all operating conditions, including emergency manual operation.
• IEC 60947-2 Certified: Tested and certified to the international standard for low-voltage switchgear, ensuring acceptance by classification societies (DNV, Lloyd's, ABS, BV) and compliance with global electrical codes.
• Proven Marine Heritage: Hyundai HAT series ACBs are installed on hundreds of vessels built at Hyundai Heavy Industries — the world's largest shipbuilder. The salt-air, vibration, and temperature cycling experienced in marine service exceeds typical shore-based industrial conditions.
• Compact Footprint: Despite its 2500A rating, the HAT 25 maintains a compact form factor relative to European and Japanese equivalents — valuable in switchboard designs where space is at a premium.
• Front-Connected Design: Line and load terminals are accessible from the front of the breaker, simplifying switchboard construction and reducing the depth required for cable entry compartments.

Industrial & Marine Applications

The Hyundai HAT 25 2500A air circuit breaker serves as primary protection for the highest-current circuits in industrial and marine electrical distribution systems. Its 2500-ampere rating and 660V capability address the most demanding low-voltage protection requirements:

Marine Main Switchboards

On commercial vessels, offshore platforms, and FPSO installations, the HAT 25 protects main generator outputs (typically 1500-2500kW at 440V or 690V), main bus tie circuits, and large motor feeders for bow thrusters, cargo pumps, and propulsion systems. The 660V rating supports modern 690V marine distribution systems that reduce cable sizes and voltage drop on large vessels. Draw-out construction permits breaker removal for maintenance during port calls without disrupting shipboard power.

Industrial Power Distribution

Manufacturing plants, steel mills, cement plants, and petrochemical facilities use 2500A ACBs at the main distribution board (MDB) level, protecting transformer secondaries from 2000-3000kVA dry-type or oil-filled transformers. The AOR-1S-AS/15 trip unit's selective coordination capability ensures that faults on individual feeder breakers do not cause unnecessary main breaker trips — maintaining production continuity.

Data Center & Critical Facility Infrastructure

Large data centers, hospitals, and telecommunications facilities require 2500A-rated breakers at the service entrance and automatic transfer switch (ATS) panels. The electronic trip unit provides the precise coordination data required for arc flash studies — reducing incident energy levels and improving worker safety during maintenance procedures.

Renewable Energy & Utility-Scale Projects

Solar farm inverters, wind turbine switchgear, and battery energy storage systems (BESS) require robust DC and AC protection at the collection point. The HAT 25's 660V rating accommodates the elevated voltages present in modern utility-scale renewable installations. The ground fault protection function is essential for ungrounded and high-resistance grounded systems common in generator-based installations.

Commercial Building Main Service

High-rise buildings, shopping malls, and large institutional complexes with 3000A-4000A main services use 2500A ACBs as the main breaker with additional feeder breakers in separate switchboard sections. The electronic trip unit's adjustable settings accommodate future service upgrades without breaker replacement.

AOR-1S-AS/15 Electronic Trip Unit Explained

The AOR-1S-AS/15 is a digital protection relay that transforms the HAT 25 from a simple on/off switching device into an intelligent protective device capable of sophisticated power system coordination. Understanding its four protective functions is essential for proper application:

Long-Time Delay (LTD / L-Function)

The long-time element provides overload protection with an inverse-time characteristic — the higher the overload current, the faster the trip. Settings typically range from 0.4 to 1.0 times the breaker rating, with time bands from 2 to 30 seconds at 6x pickup. This function protects cables and transformers from sustained overcurrent conditions.

Short-Time Delay (STD / S-Function)

The short-time element provides fault protection with an intentional time delay (typically 0.1 to 0.5 seconds) to allow downstream breakers to clear local faults first. This is the key to selective coordination — the main breaker "waits" to see if the feeder breaker clears the fault before tripping itself. Settings range from 2x to 10x the breaker rating.

Instantaneous (INST / I-Function)

The instantaneous element trips with no intentional delay for currents exceeding a high setpoint — typically 8x to 15x the breaker rating. This function provides the fastest possible clearing of catastrophic faults (bolted three-phase faults) where every millisecond matters for equipment survival. The I-function can be disabled or set "OFF" if full selectivity is required.

Ground Fault (GF / G-Function)

The ground fault element senses the vector sum of phase currents (Ig = Ia + Ib + Ic). In a healthy system, this sum is zero. During a ground fault, the imbalance produces a non-zero residual current that the GF element detects. Settings range from 20% to 60% of breaker rating with time delays from 0.1 to 0.5 seconds — providing personnel protection and preventing fire hazards from arcing ground faults.

Why Buy From Aeliya Marine Tech?

Aeliya Marine Tech has established itself as a premier global supplier of industrial electrical equipment, marine automation systems, and power distribution components. Our technical expertise in circuit breakers, switchgear, and protective relaying ensures you receive not just a product, but a solution validated for your application.

• Functional Testing & Certification: Every air circuit breaker we sell undergoes mechanical operation testing, insulation resistance testing (megger), contact resistance measurement (micro-ohm), and trip unit calibration verification. Test reports are available upon request.
• 30-Day Warranty: All ACBs carry our standard 30-day functional warranty. If the breaker fails to close, open, or trip within specifications within 30 days of delivery, we provide replacement or refund.
• Free Global Shipping: We ship worldwide using industrial-grade packaging with shock-absorbing cradles, moisture barriers, and desiccant. ACBs are heavy — our freight team handles all logistics.
• Technical Pre-Sales Support: Our engineers review your single-line diagrams, fault current studies, and coordination curves to confirm the HAT 25 is properly rated and set for your installation. We can also advise on retrofit compatibility with existing switchgear from ABB, Schneider, Siemens, and Mitsubishi.
• Large Inventory: We maintain stock of ACBs from 800A to 6300A ratings across multiple manufacturers. If the HAT 25 is not the exact match for your application, we can source the correct unit quickly.
• Proven Track Record: We have supplied air circuit breakers to shipyards, power plants, oil refineries, and data centers across 80+ countries. Our customers return because we deliver reliable equipment at competitive prices.

How to Order & Installation Guidance

Purchasing your Hyundai HAT 25 air circuit breaker from Aeliya Marine Tech follows a simple process designed for industrial procurement efficiency:

1. Request Quote or Buy Online: Click "Buy Now" above or contact our sales team for a formal quotation including freight costs and delivery schedule.
2. Technical Verification: Provide your switchboard manufacturer, available mounting dimensions, and upstream fault current level. Our team confirms mechanical and electrical compatibility.
3. Secure Payment: Wire transfer, credit card, and NET-30 terms (qualified accounts) are accepted. Pro-forma invoice provided upon request.
4. Shipping & Documentation: Your breaker ships in custom industrial crating with a packing list, test certificate, and commercial invoice. HS codes and certificates of origin are provided for international orders.
5. Installation Support: Our engineers are available to guide installation, including racking procedures, control wiring, CT polarity verification, and trip unit setting recommendations.

Installation Notes

The Hyundai HAT 25 is designed for installation in IEC-standard switchboards with 800mm or 1000mm wide cubicles. The draw-out cassette must be mounted on a flat, rigid base frame with proper alignment to ensure smooth racking operation. Connect main busbars using the rated torque specifications — undertorqued connections overheat; overtorqued connections damage conductor material. The 24V DC control circuit requires a reliable power source (typically from the switchboard DC distribution system or a dedicated control power transformer with rectifier). Commission the AOR-1S-AS/15 trip unit by entering the breaker rating, CT ratio, and desired protection curve settings through the front panel keypad.

Related Products You May Also Need

• Air Circuit Breakers 800A-6300A — Browse our full inventory of ACBs from Hyundai, ABB, Schneider, Siemens, and Mitsubishi.
• Draw-Out Circuit Breaker Cassette Assemblies — Cradles, racking mechanisms, and shutter assemblies for withdrawable breaker installations.
• Current Transformers & Potential Transformers — Instrument transformers for metering and protection applications.
• Low Voltage Switchgear Components — Busbar systems, bus couplers, and distribution boards for ACB integration.
• Breaker Accessories & Spare Parts — Auxiliary contacts, shunt trips, undervoltage releases, and arc chutes.

External Technical Resources

• Hyundai Heavy Industries — Wikipedia — Overview of HHI's history as the world's largest shipbuilder and industrial conglomerate.
• IEC — International Electrotechnical Commission — Access to IEC 60947-2 standard for low-voltage circuit breakers and related switchgear standards.
• NEMA Standards Publication — North American standards for low-voltage switchgear including NEMA AB1 for molded case circuit breakers.
• IEEE Power & Energy Society — Technical resources on power system protection, coordination studies, and arc flash analysis.

Frequently Asked Questions (FAQ)