Intelligent Air Circuit Breaker

In scenarios involving large currents such as the main incoming line of the factory or the main distribution panel of large residential areas, the shortcomings of ordinary plastic-encased circuit breakers are quite prominent and they cannot meet the actual distribution requirements: the maximum rated current is only 630A, which is far from meeting the load-bearing requirements of large current circuits, and it is prone to overloading and burning; the breaking capacity is insufficient, and when encountering short circuits, it cannot quickly cut off the current, which is likely to lead to the expansion of faults; it lacks intelligent functions, unable to monitor core parameters such as current and voltage, and also cannot be remotely managed. Operators need to frequently go to the site for inspection and operation, which is time-consuming and labor-intensive, and it is also prone to missing potential safety hazards. The Intelligent Air Circuit Breaker is specially designed for large current low-voltage power distribution, taking into account both protection and intelligent management, and fills the gap in compatibility of ordinary plastic-encased circuit breakers.

Core Value

Intelligent Air Circuit Breaker focuses on the core requirements of low-voltage power distribution with high current capacity, with "high current carrying capacity + intelligent and convenient management" as its core. It differs from ordinary plastic housing circuit breakers. Each highlight is tailored to the actual usage needs of the purchasers, ensuring both power distribution safety and improved management efficiency.

Super large current carrying capacity, suitable for various large circuit scenarios: The rated current can reach 6300A, covering the full range from 630A to 6300A, far exceeding the maximum carrying capacity of ordinary plastic housing circuit breakers. It can easily adapt to large current scenarios such as factory low-voltage main incoming lines, data center low-voltage main incoming lines, and large residential area low-voltage main incoming lines, without worrying about equipment damage or line failures caused by overcurrent, ensuring the stable operation of the large current power distribution system and meeting the core requirements of large current power distribution.

Intelligent monitoring + remote communication, management is more convenient and efficient: Equipped with a professional intelligent protection module, it can accurately measure core power distribution parameters such as current, voltage, power, and energy, and monitor the operating status of the line in real time, promptly detecting abnormal hazards; equipped with RS485 communication function, it can transmit operating data to the control room in real time, enabling remote viewing and remote control, without requiring operators to go to the site, significantly saving labor costs and improving power distribution management efficiency, adapting to the development trend of modern power distribution management and solving the cumbersome problems of traditional power distribution management.

Technical Specifications

Balancing reliability and installation ease

Junray Electrical pays attention to the refinement of product details. Considering the usage scenarios of high-current low-voltage power distribution, every design aspect takes into account both reliability and practicality, ensuring the equipment operates stably for a long time and reducing installation and maintenance costs. The Intelligent Air Circuit Breaker adopts a dedicated structure design for high-current applications, with strong carrying capacity, capable of stably adapting to high-current circuits and avoiding equipment failures caused by excessive current; it is equipped with high-performance intelligent modules, with precise measurement and stable communication, ensuring smooth remote management functions; it is equipped with a reliable operating mechanism, with precise opening and closing actions and quick switching, with an extremely low failure rate, ensuring that the circuit can be quickly cut off in case of a fault, safeguarding power distribution safety; it adopts standardized installation design, which can be directly installed in low-voltage distribution cabinets, without the need to modify the cabinet structure, making the installation convenient and suitable for various distribution cabinet layouts, thereby improving installation efficiency.

Full-scenario coverage

With its superior current-carrying capacity and intelligent management advantages, Intelligent Air Circuit Breaker is widely applied in various large-current low-voltage power distribution scenarios, becoming the standard component for large-current low-voltage power distribution. It precisely meets the usage requirements of different scenarios. In the factory main incoming line scenario, it is adapted to the factory's low-voltage main incoming line, carrying the overall power load of the factory and ensuring the stability of the factory's production power supply; in the low-voltage main distribution scenario, it is adapted to various low-voltage main distribution systems, with intelligent monitoring and remote control, enhancing the power distribution management level; in the data center scenario, it is adapted to the low-voltage main incoming line of the data center, ensuring the power supply safety of core equipment and avoiding business interruption caused by large current faults; in the large residential area scenario, it is adapted to the low-voltage main incoming line of large residential areas, carrying the overall power demand of the residential area, and ensuring the stability of residents' daily power supply.

Purchase Selection Guide

For large current low-voltage power distribution scenarios, when purchasing Intelligent Air Circuit Breaker, two key points need to be focused on to avoid selection errors: First, confirm the actual current load. Based on the low-voltage main incoming current of factories, data centers, etc., select the equipment with the corresponding rated current (630A~6300A) to ensure the carrying capacity meets the requirements. Second, clarify the intelligent requirements. This product comes with RS485 communication and intelligent measurement functions, which can directly adapt to the remote management requirements without the need for additional equipment installation, significantly reducing procurement and operation costs. Junray Electrical can provide professional selection guidance to help customers avoid selection mistakes and accurately match their needs.

Why choose us?

As a professional Manufacturer, Supplier and Factory of High and Low Voltage Components in China, Junray Electrical strictly follows the national standards for intelligent air circuit breakers. All products undergo three core tests: power-on debugging, breaking test, and intelligent function test to ensure that each factory-delivered equipment can operate stably, pass engineering acceptance smoothly, and eliminate quality risks. We offer current customization and breaking capacity customization.

Contact us now to ensure the safety of high-current power distribution, enhance management efficiency, and facilitate the smooth progress of various high-current low-voltage power distribution projects.

Retrofit Case Study

I. Project Overview

This project involves the retrofit of the main power distribution system for a large-scale intelligent manufacturing workshop. The facility is equipped with a 2000kVA main transformer and utilizes a split-bus configuration for the low-voltage busbars. Downstream loads include numerous heavy-duty, high-impact devices such as CNC machine tools, servo equipment, variable-frequency drive units, and air compressors. The original main low-voltage incomer utilized outdated, high-capacity molded-case circuit breakers (MCCBs). These units suffered from issues such as a lack of precise three-stage protection, inability to perform intelligent parameter setting, lack of selectivity between upstream and downstream devices, and insufficient short-circuit breaking capacity. Repeatedly, minor faults at the load end triggered the main switch to trip (sympathetic tripping), causing widespread production shutdowns across the plant and resulting in significant economic losses.

To optimize the tiered low-voltage protection system, eliminate sympathetic tripping, and enhance busbar short-circuit withstand capability, the project involves replacing all main incomer and bus-tie switches with intelligent air circuit breakers (ACBs). These serve as the primary protection switches for the entire low-voltage distribution system, ensuring system stability and production continuity.

II. Issues Prior to Retrofit

Lack of selectivity and severe sympathetic tripping: The original MCCB main switches lacked short-time delay protection; short-circuit or overload faults in downstream circuits caused the main switch to trip directly, resulting in total plant power outages and massive losses.

Insufficient short-circuit breaking capacity: Due to concentrated loads and high short-circuit currents, the ultimate breaking capacity of standard MCCBs was inadequate, posing high risks of switch ablation and busbar arcing during faults.

Lack of precise intelligent settings: Parameters for long-time delay, short-time delay, and instantaneous tripping could not be finely adjusted or matched with downstream protection settings, leading to disorganized protection coordination.

No data monitoring or hazard prediction: The system lacked functions for monitoring current and temperature or recording faults, making it impossible to anticipate overloads, overheating, or abnormal load conditions.

Inability to implement bus-tie interlocking and automatic transfer: The legacy switches lacked intelligent interlocking logic, preventing safe, automatic switching between the two busbar sections and resulting in poor power supply redundancy. 

III. Equipment Configuration Plan

Based on the plant's total load capacity and standards for selective protection in low-voltage distribution, the low-voltage incoming feeder cabinets and bus-tie cabinets are uniformly equipped with DW45 intelligent air circuit breakers (ACBs). These serve as the primary system protection, delivering three-stage precision protection, intelligent monitoring, electrical interlocking, and automatic bus transfer (ABT) capabilities.

Core Equipment Specifications

Model: DW45-2000/3P Intelligent Air Circuit Breaker

Rated Current: 1600A (matched to the low-voltage main incoming feed of a 2000kVA transformer)

Rated Voltage: 400V low-voltage distribution system

Breaking Capacity: Ultimate short-circuit breaking capacity >50kA; withstands severe industrial short-circuit surges

Protection Characteristics: LSIG three-stage protection (long-time delay overload, short-time delay short-circuit, instantaneous short-circuit)

Intelligent Functions: Current/voltage monitoring, temperature early warning, fault logging, remote communication, and precision-adjustable settings

Operation Modes: Dual-mode operation—motorized energy storage/remote switching and local manual operation

Interlock Logic: Electrical interlocking between dual incoming feeds and the bus-tie; supports automatic bus transfer (ABT) and prevents short-circuits caused by parallel connection

IV. Construction and Application Highlights

Achieves perfect selective protection and eliminates non-selective tripping: By coordinating short-time delay settings with downstream MCCBs and MCBs, the system ensures that "terminal faults trip branch circuits while main-line faults trip the main line," thoroughly resolving the persistent issue of plant-wide blackouts.

Ultra-high short-circuit breaking capacity and busbar safety assurance: The ACB's breaking capacity far exceeds that of molded-case circuit breakers (MCCBs), enabling rapid clearance of short-circuit faults near the busbar and safeguarding the low-voltage busbar and main transformer.

Intelligent precision settings tailored to industrial loads: Protection curves are finely tuned to accommodate servo-driven surge loads, harmonics from variable frequency drives (VFDs), and frequent start-stop operations, ensuring no nuisance tripping or failure to trip.

Robust automatic bus transfer (ABT) logic: Enables mutual backup between the two busbar sections with automatic switching upon a single-section fault, significantly enhancing power supply reliability. Intelligent O&M and remote monitoring capabilities: Real-time uploading of load data, fault records, and temperature rise data enables the early detection of potential hazards and facilitates intelligent power distribution management.

V. Operational Results After Retrofitting

Complete resolution of cascading trip issues: Following the retrofit, branch faults resulted only in the isolation of the specific affected circuit; there were zero instances of nuisance tripping on the main breaker, ensuring continuous production across the facility.

Reliable short-circuit fault clearing: Near-end short-circuit faults are interrupted rapidly without switch ablation or busbar arcing, significantly enhancing the power distribution system's fault resilience.

Precise and controllable load monitoring: Real-time monitoring of three-phase currents, load rates, and temperature rise eliminates long-term hidden overloads and prevents equipment burnout caused by aging.

Reliable dual-power switching: Automatic switching during busbar faults operates correctly with no power outage gaps, significantly upgrading power supply redundancy and stability.

Full compliance with acceptance standards: Hierarchical protection logic and setting values are properly configured, ensuring the system passed electrical safety standardization acceptance inspections on the first attempt.

VI. Case Summary

The Air Circuit Breaker (ACB)—also known as a universal circuit breaker—serves as the highest-level main protection switch in low-voltage power distribution systems, specifically designed for transformer main incomers, busbar tie-breakers, and high-capacity main circuits. Compared to Molded Case Circuit Breakers (MCCBs), ACBs offer higher capacity and breaking ratings, feature three-stage selective protection, support intelligent settings, and enable automatic transfer switching. They are critical components for resolving cascading trips, busbar faults, and large-scale power outages, making them essential standard equipment for all large-to-medium-sized factories, commercial complexes, and high-capacity power distribution stations.