XL633 Low-Voltage Seamless Switching Cabinet

Product Overview

With the transformation and upgrading of China's economic structure, traditional mining and manufacturing enterprises face pressure to transform and enhance efficiency. The continuity of the production process is a fundamental indicator for ensuring benefits, and power supply continuity has become a critical production metric. In various fields, rapid switching of low-voltage primary distribution serves as an important strategy to address power supply continuity.

Distribution systems may experience momentary power outages due to external short circuits, voltage sags, etc. Traditional dual-power transfer switches and low-voltage automatic transfer switches initiate switching based on voltage loss. However, after power is restored, the motor control circuits of critical loads may have already tripped, failing to meet continuity requirements. Additionally, a large number of motors that were cut off need to be restarted; some processes may suffer irreversible damage. Enterprises must expend significant time and considerable costs to resume production.

Guogao Electric has been dedicated to power switching for over 10 years. As a drafter of industry standards for power distribution switching devices, the company possesses extensive project experience and achievements. The XL633 Low-Voltage Bumpless Transfer Cabinet integrates rapid switching technology, automatic synchronization technology, inrush current suppression technology, and online load monitoring technology to ensure bumpless transfer of power systems, fundamentally improving the reliability of power supply for industrial enterprises. Its typical structure is shown in the figure below:

Bumpless Transfer Cabinet Description

☆  1QF\2QF are molded case circuit breakers. The number of poles, frame current, and brand of the circuit breakers can all be customized. This cabinet size supports operating currents up to 250A.

☆  Bumpless transfer is specifically designed for 400V systems and is applicable to both three-phase three-wire and three-phase four-wire systems.

☆  KK1 to KK4 are default 2P miniature circuit breakers, while KK5 to KK7 are default 4P miniature circuit breakers, with customizable capacities.

☆  The system supports multiple modes, including manual parallel closing mode.

☆  Printing function is optional.

Voltage Sag Management Partner, Working Principle of Low-Voltage Bumpless Transfer Cabinet, Bumpless Transfer Cabinet

Main Product Features

☆  Manual parallel switching with zero power interruption for loads.

☆  Switching time less than 100ms.

☆  Applicable to various load types, especially for continuous motor operation scenarios.

☆  Standard cabinet type, integrated solution for rapid switching.      

☆  All switching parameters are stored holographically and retained for 10 years without loss.

Main Product Functions

Manual Parallel Switching:

1. When the main power source and backup power source meet the parallel closing conditions, the controller issues a command to close the parallel circuit, connecting the backup power source to form a temporary parallel operation state. After confirming successful parallel closing of the backup power source, the main power source is tripped after a delay. This function is highly practical for scenarios where the main power source requires maintenance but loads cannot be shut down.

2. When the main and backup power sources do not meet parallel closing conditions, the controller dynamically tracks changes in voltage, frequency, and phase. It automatically closes the parallel circuit when conditions are met. If parallel closing cannot be achieved within the set time, the operation is automatically aborted, and manual parallel tracking can be restarted until successful.

Rapid Switching:

1. When the main incoming line loses power due to an external fault, the device quickly detects the voltage loss and performs switching according to the set sequence, such as simultaneous switching (closing the backup switch while tripping the main switch) or sequential switching (tripping the main switch first, then closing the backup switch).

2. In other scenarios, such as relay protection or accidental switch tripping, rapid switching is performed according to the set sequence.

Synchronous Switching:

If the main power source fails and the load voltage drops rapidly, and the window for rapid switching is missed, the system automatically enters synchronous switching mode. It predicts the next closing point, automatically calculates the switch opening and closing times, and issues commands in advance to ensure bumpless impact at the moment of closing.

Residual Voltage Switching:

When neither rapid nor synchronous switching is possible, the system automatically initiates residual voltage switching based on the set undervoltage value. The switching sequence follows the preset order to ensure continuous system operation with minimal power interruption.

Long-Delay Switching:

After detecting an abnormality in the main power source, the device starts a timer. If rapid, synchronous, or residual voltage switching is not feasible, long-delay switching is initiated once the delay time elapses. This type of action typically occurs hundreds of milliseconds later.