Overview

The HR3 series fuse-type disconnectors are designed for use in AC 50Hz, 400V distribution systems with rated currents up to 1000A, providing short-circuit protection and overload protection for cables and conductors. Under normal conditions, they are intended for infrequent manual making and breaking of normal load currents and overload currents. In the event of a short circuit, the current is interrupted by the fuse link.

Compliance standards: GB 14048.3, IEC 60947-3.

Model Designation and Meaning

Normal Operating Conditions

● The ambient air temperature shall not exceed +40℃ and shall not be lower than -35℃.

● The altitude of the installation site shall not exceed 5000 m.

● Humidity: At the maximum temperature of +40℃, the relative humidity of the air shall not exceed 50 %. Higher relative humidity is permitted at lower temperatures, for example, 90 % at 20℃. Special measures shall be taken for condensation that occasionally occurs due to temperature changes.

● The pollution degree of the surrounding environment is Class 3.

● The switch shall be installed in a place free from significant sway, shock, vibration, rain and snow exposure. The installation site shall also be free from explosive media, and shall contain no gases or dust sufficient to corrode metals and damage insulation.

Main Parameters and Technical Performance

Structural Features

The fuse-type disconnector (hereinafter referred to as "the switch") is a combined device integrating a fuse and a knife switch, embodying the basic performance of both components. Under normal power supply conditions, making and breaking the circuit is performed by the knife switch. When the line or electrical equipment is overloaded or short-circuited, the fuse element blows, promptly interrupting the fault current.

Front-operated, front-maintenance switches feature a central door for maintenance and fuse replacement, primarily designed for installation in BDL distribution panels.

Front-operated, rear-maintenance switches are mainly intended for BSL distribution panels.

Side-operated, front-maintenance switches can be configured into enclosed power distribution boxes.

Knife switches with a rated current of 1000 A and below are equipped with safety baffles and arc-extinguishing chambers. The arc-extinguishing chamber is constructed from phenolic laminate and stamped steel plates, riveted together.

The fuse element is mounted on an insulated crossbeam with springs and locking plates. This design prevents the fuse from becoming loose during normal operation. After the fuse element blows due to a line fault, the fuse can be easily replaced by simply pressing the locking plate.

Overall and Installation Dimensions (mm)

Overall and Installation Dimensions of HR3/32 Series Switches

Overall and Installation Dimensions of HR3/33 Series Switches

Note: The switch is designed with anti-misoperation interlock and can only be opened when it is rotated 90° to its maximum position.

Overall and Installation Dimensions of HR3/34 Series Switches

Note: The dimensions are taken when the connecting rod is at its maximum position with the switch in the closed state.