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Main purpose

The fuse is suitable for line overload and short-circuit protection in the distribution equipment of industrial electrical equipment with AC rated frequency of 50Hz, rated voltage of AC to 690V, DC 250V to 440V and rated cunent to 1250A.
1.2Type and specification

Type and specification

Fuse is divided into six sizes according to the size of fuse tube. Each size has conesponding rated current range. Refer to main technical parameters for rated cun ent level of fuse of various sizes. The fuse can be equipped with an impactor according to the user’s requirements, and the impactor is generally located directly above the fuse contact.

Nomenclature of fuses

Normal working conditions

◆Ambient air temperature
The ambient air temperature shall not exceed 40° C, the average value measured in 24 hours shall not exceed 35 C, and the average value measured in one year shall be lower than this value.
The minimum ambient air temperatureis- 5 C.
◆Altitude
The altitude of the installation site shall not exceed 2000m.
◆Atmospheric conditions
Its relative humidity shall not exceed 50% at the maximum temperatureof40° C
A higher relative humidity can be obtained at a lower temperature, for example, up to 90% at 20C.
Under these conditions, moderate condensation may occur by chance due to temperature changes. Without consultation with the manufacturer, the fuse cannot be installed in the place with salt mist or abnormal industrial deposit.
◆Voltage
The maximum system voltage shall not exceed 1 10% of the rated fuse voltage.
For fuse with rated voltage of 690V AC and 250V 1440V DC, the maximum system voltage shall not exceed 105% of rated voltage of fuse.

Normal installation conditions

◆Installation category
The installation category of fuse is class I.
◆Pollution level
The anti pollution degree of fuse shall not be lower than level3.
◆Installation mode
The fuse can be installed vertically, horizontally or obliquely in the workplace without significant shaking and impact vibration.

Breaking range and use category

The fuse link for fuse is a fuse link with general purpose and full range breaking capacity, i.e. “gG” fuse link.

Structural features and working principle

The fuse consists of fuse base and fuse link. The fuse base is composed of base contact, base plate, etc. The fuse link is composed of fuse tube, melt, quartz sand, knife type contact, etc.
When the fuse is installed in the circuit, when the current passing through the fuse exceeds a certain value for a sufficient time, the melt in the fuse body will be fused, and the arc generated when the fuse is fused by quartz sand in the fuse tube will be extinguished, so as to achieve the purpose of breaking the circuit.
When the melt is blown, the indicator on the fuse link will pop up, indicating that the fuse link is blown.
For the fuse equipped with an impactor, when the melt is fused, the impactor will pop out automatically. The user only needs to install a micro-switch or a suitable signal sending device (selected and purchased by the user) in front of the impactor, and then the required signal can be obtained after the fuse is fused.

Main technical parameters

Main technical parameters of fuse are shown in Table 1

Outline, installation dimension and weight of fuse

◆Outline, installation dimension and weight of fuse base
See Figure 1 and table 2 for the outline and installation dimension of fuse base, and see Table 2 for the weight of fuse base.

Table 2 (Continued)

Boundary dimension and weight of fuse link

weight of fuse link

See Figure 2 and table 3 for the boundary dimension of fuse link, and see Table 3 for the

Figure 2 Boundary dimension of fuse link

Table 3 boundary dimension and weight of fuse link

5. Installation, use and maintenance of fuse
The fuse shall be installed indoors or in a cabinet that will not be affected by rain and snow, and shall not be exposed and installed in a place easy to touch.When installing the fuse, ensure that the electrical clearance is greater than 8 mm and the creepage distance is greater than 10 mm.In the circuit, the cross-sectional area of the connecting wire is recommended as the value in Table 4.

Table 4 sectional area of connecting wire of fuse

When the fuse link is blown, a new fuse link with the same model, size and rated current as the original fuse link must be replaced instead of copper wire.
The replacement of fuse links shall be carried out by professionals using special fuse carriers.
When replacing the fuse link, it must be carried out under the condition of no load, preferably when the power supply is cut off. It is absolutely not allowed to use the fuse to cut off or connect the load when the switch is used. After replacing the fuse link, ensure that the contact between the fuse link and the base contact is in good contact.
When switching off the power supply and replacing the fuse link, please remove the dust and other dirt on the fuse base, especially the contact of the base, so that the fuse is in good working condition.
During operation, the indicator of fuse link shall be checked frequently so as to discover the single-phase or missing phase operation in time.

Transportation and storage of fuse

The fuse shall be protected from rain and snow during transportation and storage. The free drop height of the whole box fuse shall not be greater than 250mm.
Fuses shall be stored in a place with air circulation and dry environment, and the stacking height shall not exceed six layers.

Unpacking and inspection of fuse

After unpacking, first check whether the nameplate of the fuse is consistent with the packing list and the mark on the packing box, then check whether the fastener on the fuse base or fuse link is loose or falling o比 check whether the porcelain tube of the fuse link is cracked or cracked, check whether the quartz sand in the fuse block is leaking out, and check whether the fuse is soaked or attacked by water. If the above conditions are found, the fuse cannot be put into use, and the manufacturer shall be contacted in time.
The fuse box shall contain product certificate, packing list and operation instruction.

Ordering instructions

When ordering fuses, the model, specification, quantity and current grade of corresponding fuse links shall be indicated. The fuse base and fuse link can be ordered separately.
For fuses of special specifications and current levels, the manufacturer shall be consulted when ordering.