Description:

The ABB 07KT93​ is a specific article number for a 3-pole molded case circuit breaker (MCCB) from ABB’s Tmax XT series. This compact, high-performance breaker is designed to provide reliable protection for electrical circuits against overloads and short-circuits. With a rated current of 80A and a high breaking capacity, it is a core component in industrial power distribution panels, motor control centers (MCCs), and commercial electrical installations, ensuring safety and equipment protection.

Application Scenarios:

In a manufacturing plant’s motor control center (MCC), a critical 50 HP pump motor is protected by a starter. The feeder circuit supplying power to this starter requires precise protection against sustained overloads that could overheat the wiring and against violent short-circuits. The ABB 07KT93​ circuit breaker is installed as this feeder’s primary protection device. Its thermal-magnetic trip unit continuously monitors the current. A slow, sustained overload causes the bi-metal strip to heat and bend, tripping the mechanism after a timed delay suitable for motor starting currents. A sudden bolted short-circuit near the starter causes the magnetic solenoid to react instantly, forcing the contacts open within milliseconds to interrupt the massive fault current, protecting the cabling, starter, and motor from catastrophic damage and preventing potential fire hazards.

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Technical Principles and Innovative Values:

The ABB 07KT93​ embodies the essential principles of circuit protection through a robust, time-tested dual-element design, optimized for performance and safety.

Innovation Point 1: Dual-Element, Coordinated Trip Mechanism:​ The breaker integrates two distinct, coordinated protection mechanisms in one unit. The thermal element​ (a bi-metal strip) provides inverse-time protection against overloads. The higher the overload current, the faster it trips, accurately modeling cable heating. The magnetic element​ (a solenoid) provides instantaneous protection against high-magnitude short-circuit currents, triggering within one cycle. This combination ensures selective coordination, allowing downstream breakers to clear minor faults without unnecessarily shutting off the entire upstream circuit.

Innovation Point 2: Advanced Arc Quenching and Construction:​ Inside the compact housing, the 07KT93​ features an efficient arc chute design. When the contacts open under fault conditions, the electric arc is driven into a series of splitter plates that cool, elongate, and extinguish it rapidly. This design, combined with robust contact materials, ensures the high breaking capacity (Icu) is reliably achieved, safely interrupting severe fault currents and maintaining the dielectric strength of the open contacts.

Innovation Point 3: Ergonomic and Safe Design:​ The 07KT93​ is designed for operator safety and ease of use. It features a clear ON/OFF handle indication, a trip-indicating flag (showing whether a fault caused the disconnect), and a patented “flag and padlock” system for secure lockout/tagout (LOTO) procedures during maintenance. Its compact, square-front design allows for dense panel mounting, saving valuable enclosure space.

Application Cases and Industry Value:

Case 1: Commercial Building Main Distribution Board Upgrade:​ A mid-rise office building undergoing an electrical upgrade required modern, reliable protection for its sub-feeder circuits running to tenant distribution panels. The electrician selected the ABB 07KT93​ for its 80A rating, perfect for 63-80A feeder circuits. Its compact size allowed more circuits in the existing panelboard. During commissioning, a fault occurred due to damaged cable insulation during installation. The 07KT93​ cleared the short-circuit fault instantly and reliably, preventing damage to the new panel buswork. The building manager appreciated the robust protection, and the maintenance team valued the clear trip indication for rapid fault location.

Case 2: Industrial Feeder Protection for Multiple Motors:​ In a water treatment plant, a single feeder from a main panel supplies a group of three smaller mixer motors, each protected by its own starter and overload relay. The ABB 07KT93​ was chosen as the group feeder breaker. Its thermal setting was calibrated above the sum of the motors’ full-load currents plus diversity, allowing all motors to start and run normally. However, it protected the shared cable from overload. When a downstream short occurred in one motor branch, the magnetic trip of the 07KT93​ operated, isolating the entire faulty feeder and allowing the other two healthy mixer lines (protected by their own downstream devices) to remain operational, minimizing process disruption.

Related Product Combination Solutions:

ABB Tmax XT Trip Units (TMD, EMO, PR221/222):​ The 07KT93​ typically has a fixed thermal-magnetic (TMD) unit. Other breakers in the series offer electronic trip units (e.g., PR221DS) with adjustable protection settings and communication.

ABB Auxiliary Contacts (e.g., A9A26901):​ Add-on modules that provide NO/NC signals for remote indication of the breaker’s status (ON/OFF/TRIPPED).

ABB Undervoltage Release (UVT) or Shunt Release (MN):​ Accessories that allow the remote tripping (MN) or automatic tripping on power loss (UVT) of the breaker.

ABB Rotary Handle Mechanism:​ Allows the operation of the breaker from outside a closed cabinet door, enhancing safety and convenience.

ABB SACE Emax 2 Air Circuit Breaker (ACB):​ A larger upstream breaker that would provide main incomer protection; the 07KT93​ would be a downstream feeder breaker, and their trip curves should be coordinated for selective tripping.

ABB Motor Starter (e.g., with MS116 Contactor & Overload):​ A direct downstream device the 07KT93​ would protect as a feeder or backup short-circuit protector.

ABB System Pro M Compact S200/S280 Miniature Circuit Breakers (MCBs):​ These would be used for final sub-circuits further downstream from the 07KT93​ feeder breaker.

Installation, Maintenance, and Full-Cycle Support:

Installation of the ABB 07KT93​ must be performed by a qualified electrician following local electrical codes. The breaker is mounted on a DIN rail or a fixed mounting plate. Power cables are connected to the front terminals with appropriate torque settings. Proper sizing of the upstream cables and coordination with downstream protective devices is crucial. Before energization, ensure the handle is in the OFF position and verify the trip settings match the circuit design requirements.

Routine maintenance involves a visual inspection for signs of damage, overheating, or dust accumulation. The mechanical operation should be tested periodically by switching the handle ON and OFF. It is recommended to perform primary injection testing periodically to verify the trip curve characteristics. The breaker itself is sealed and not field-repairable; if a fault in the mechanism is suspected, it should be replaced. We supply the genuine ABB 07KT93​ circuit breaker. Our technical support can assist with compatibility checks, coordination studies, and guidance on proper installation to ensure your electrical distribution system remains safe, reliable, and compliant.

Contact us for the genuine ABB 07KT93 circuit breaker and ensure robust and reliable protection for your electrical distribution network.