Views: 8 Author: Site Editor Publish Time: 2024-10-09 Origin: Site
Film capacitors normally last for a long time, usually more than seven or eight years. However, some film capacitors in circuits burst after a short period of use. What's going on? The following are some common reasons for film capacitor bursts.
1. Improper capacitor selection.
Capacitors must be selected correctly. There are many types of film capacitors. For example, if it is a conventional circuit, CBB22 capacitors are generally used. If the voltage is higher and the current is larger, we can use CBB81 or MMKP82 capacitors.Or there is insufficient voltage margin during selection, etc., which may cause the film capacitor to burst due to incorrect capacitor selection.
2. The material of the film capacitor is too poor.
Film capacitors have a high level of production automation, so theoretically, the cost difference between different manufacturers is not too big. However, in order to fight a price war and make their products more cost-effective, some manufacturers will compete with each other on film capacitor materials.For example, they choose inferior film from small manufacturers, or even choose cheap inferior metallized film. There are also many manufacturers in the industry who directly purchase defective products produced by metallized film manufacturers. The cost of producing film capacitors with such film is indeed very low, but the service life of the capacitors will also be very poor, and they are very prone to bursting during use.
3. The circuit temperature is too high.
The maximum temperature resistance of film capacitors is generally 105℃/110℃ (note that some cheap film capacitors have a maximum temperature resistance of only 85℃, which are obsolete products, but are still sold by many manufacturers). If there are electronic components with large heat dissipation next to the film capacitor, or the heat dissipation of the entire circuit is not very good, it is very easy for the film capacitor to burst due to excessive temperature.
4. Low voltage pretends to be high voltage.
This is a common trick used by low-priced film capacitors. Because the material cost of film capacitors accounts for a very high proportion, regular film capacitors have a 1.6 to 2 times margin for withstand voltage. In order to make their product prices more competitive, some manufacturers like to use low-rated voltage film capacitors to impersonate high-voltage capacitors. Since this type of capacitor uses less raw materials, it is smaller in size and has insufficient withstand voltage margin, making it easy for the capacitor to burst when used.
