Installation and selection of patch fuse

时间:2019-10-24 丨 预览:440 人次

The fuse current of the chip fuse is 1.5-2.0 times of the rated current. When the electrical equipment is in normal use, its fuse will not blow. When the current in the circuit exceeds 5 times of its rated current, it will Automatic fusing plays a protective effect. If the fuse blows during normal use of electrical equipment, this indicates that the current in the circuit exceeds the rated current. For this reason, the cause should be investigated immediately.

During the installation process of the chip fuse, you must first pull down the blade on the switchboard to block the power supply. It is best to use a pen to test whether there is electricity before operating. For fixing screws and washers, copper should be used, and iron should not be used temporarily. Iron will rust easily for a long time, and it will also cause poor contact. When tightening the fuse, do not use excessive force to prevent the fuse from flattening and reducing the cross-sectional area, rated current and fusing current, which will not have the desired "insurance" effect.

SMD fuses cannot be loosened to a certain extent. The main reason is that excessive looseness will cause excessive contact resistance at the joints and lead to false breaking. After the fuse is blown, it is best to ask a certified electrician to check the cause first. Users should not install it at will. Never replace the fuse with copper wire or iron wire. This is very risky. Because copper wire and iron wire cannot block the current, on the contrary The wires and equipment are overheated and burned, which may even cause a fire.

Selection tips for chip fuses

1. Normal current: First of all, we need to know that the fuse flowing through the circuit chip used in normal current. Usually we want to reduce the difference of the preset amount, and then choose the following principle: That is, the normal current must be less than the rated current and the derating factor of the product.

2. Fusing current: According to the requirements of the UL specification, the chip fuse (fuse) should be twice the rated current of the fast-acting condition. But in most cases, in order to ensure a reliable fuse, we recommend that the breaking current should be greater than 2.5 times the rated current. In addition, the melting time is very important, and it is necessary to refer to the manufacturer's figure melting characteristics to make a judgment.