Rmu Load Break Switch

The Usune RMU Load Break Switch mainly includes three types of independently developed products: indoor AC high-voltage SF6 load switches, load switch-fuse combination appliances, and cable-head mounted load switches, covering the FLN36-12D (load switch) and FLRN36-12D (load switch-fuse combination appliance) models. These products can meet the needs of diverse power distribution scenarios, and are particularly suitable for the complex operational requirements of China's power system. As a core product of Zhejiang Usune Electric Co., Ltd., this switch is manufactured in the company's modern factory, undergoing rigorous quality testing throughout the process to ensure stable and reliable performance.

Core Advantages

1. Usune has been deeply involved in the R&D and production of high-voltage electrical equipment for many years, accumulating rich experience in field applications. The RMU load break switch has been widely used in thousands of projects both domestically and internationally, verifying its adaptability and reliability in various environments.

2. The RMU Load Break Switch was independently developed by Usune's professional R&D team, absorbing advanced foreign technologies and optimizing its design to suit the actual characteristics of China's power system. Its arc-extinguishing principle, structural design, and operating mechanism all reflect deep professional expertise in the field of high-voltage switchgear.

3. The product has passed a full set of type tests, and its performance fully complies with GB 3804, GB 16926, IEC 60265, and IEC 60420 standards, demonstrating its technical authority and compliance.

4. Employing a special dynamic and static sealing structure, it boasts excellent sealing performance and is equipped with a visual pressure gauge for real-time monitoring. Reliable mechanical interlocks ensure operational safety. As a professional manufacturer, Usune provides comprehensive after-sales service, further enhancing customer trust.

Structural Features

1. The load switch and combined electrical appliances consist of a unified insulated housing, switch body, spring operating mechanism, fuse holder, and fuse tripping system. Cable-head mounted load switches are equipped with a dedicated insulated housing and a universal spring operating mechanism.

2. The upper and lower housings are cast with epoxy resin to form a sealed, gas-filled inner cavity. The rotation of the common moving contact achieves three positions: "closing," "opening," and "grounding," ensuring flexible and reliable switching.

3. The front of the mechanism box is equipped with an SF6 pressure gauge and a position indicator. The position indicator is directly linked to the moving contact drive shaft, ensuring accurate and reliable indication.

4. A pressure relief port is located at the rear of the housing. In case of internal overpressure due to a fault, gas is discharged backward, preventing forward ejection and ensuring personnel safety.

5. Reliable mechanical interlocks are provided between the load switch and the grounding switch, and between the grounding switch and the front door (panel matching) to avoid the risk of misoperation.

6. Cable-terminal mounted load switches are equipped with anti-touch front cable connectors, supporting high-voltage cable connections at both the incoming and outgoing ends, and are specifically designed for cable branches/junction boxes.

Arc Extinguishing Principle

The RMU Load Break Switch uses SF6 gas as the arc-extinguishing medium, exhibiting excellent arc-extinguishing performance. When the switch breaks the current, the moving and stationary contacts separate, generating an arc. Driven by a permanent magnetic field, the arc rotates rapidly around the contacts, achieving rapid deionization and cooling, extinguishing at the current zero-crossing point; after breaking, a double-break gap with a high level of isolation insulation is formed, resulting in strong breaking capacity, minimal contact wear, and long electrical life.

Operating Mechanism

1. Type II manual spring operating mechanism

Used for switching, closing, opening, and grounding operations of the load switch. The upper operating hole controls the grounding switch, and the lower operating hole controls the load switch; after closing, the trip spring synchronously stores energy, and the trip can only be released via a manual button or fuse signal.

2. Type II Electric Spring Operating Mechanism

Based on the manual mechanism, this design adds a motor energy storage device and a trip coil. Manual and electric operation are independent and do not interfere with each other. It supports remote control, and the operating voltage includes AC220V, DC220V, DC110V, and DC48V.

Operating Conditions

1. Normal Operating Conditions

- Ambient temperature: −25 °C ~ +40 °C
- Altitude: Not exceeding 2000m
- Humidity: Daily average relative humidity ≤95%; monthly average relative humidity ≤90%; daily average water vapor pressure ≤2.2kPa; monthly average water vapor pressure ≤1.8kPa
- Ambient air free from significant dust, smoke, corrosive/flammable gases, vapors, and salt spray pollution
- External vibration and seismic interference are negligible
- Secondary circuit induced electromagnetic interference amplitude ≤1.6kV

2. Special Operating Conditions

According to GB/T 11022-1999 "Common Technical Requirements for High Voltage Switchgear and Controlgear Standards", the switch should operate under normal conditions; if the actual operating conditions deviate from the normal range (such as altitude exceeding 2000m, excessive temperature, high humidity and easy condensation, etc.), the user needs to reach an agreement with the manufacturer.

Main Technical Parameters

Fuse Technical Parameters

Project Reference

Cas-space Rocket Launch Project

Test Report

Actual Application Cases

Case 1: Power Distribution Project in a Residential Community in Hangzhou, China A large residential community in Hangzhou, with high requirements for power supply stability and security, selected the Usune FLRN36-12D load break switch-fuse combination appliance as its core power distribution equipment after comparison. Installed in the community's substation, it is responsible for the switching and protection of power lines for 8 residential buildings (1200 households). Since its commissioning in 2024, the equipment has operated stably for over 12 months without any tripping or power outages. Its reliable interlocking design and SF6 arc-extinguishing performance effectively prevent power outages caused by fault currents, ensuring residents' normal lives. As the supplier for this project, Usune provided on-site installation guidance and regular maintenance services, earning high praise from the community property management and residents.

FAQ

Q1: What standards does the Usune RMU Load Break Switch meet, and how is its reliable performance guaranteed?

A1: The product has passed a full set of type tests, and its performance fully complies with GB 3804 "3kV～63kV AC High Voltage Load Break Switch", GB 16926 "High Voltage Load Break Switch-Fuse Combination Appliance", and IEC 60265 and IEC 60420 standards. Furthermore, the product is independently developed by Usune, with strict quality control throughout the entire process from raw material procurement to factory production and testing. Its unique dynamic and static sealing structure, real-time pressure monitoring, and reliable mechanical interlocks all ensure long-term stable operation.

Q2: Can the Usune RMU Load Break Switch be used in special environments such as high altitude and high humidity?

A2: The product is designed to be compatible with normal operating conditions (altitude ≤ 2000m, temperature −25 °C ~ +40 °C, etc.). If actual operating conditions deviate from the normal range (e.g., altitude exceeding 2000m, excessive temperature, high humidity and condensation), users need to consult with the manufacturer (Zhejiang Usune Electric Co., Ltd.) in advance. Usune's professional R&D team can provide customized solutions based on specific environments to ensure stable product operation.