understand the advantages and disadvantages of epoxy resin encapsulated film capacitors and boxed film capacitors
visit：4508次 date：2022-09-22
in the film capacitor industry, there are mainly two packaging forms of plug-in film capacitors. the first is to use epoxy resin to encapsulate, such as cbb22 metallized polypropylene capacitors, cbb81 high-voltage capacitors, cbb13, cl21 metallized polyester capacitors, cl21x and other capacitors. the second is plastic shell packaging, also known as box capacitors, such as mmkp82 double-sided metallized capacitors, mpb box capacitors, and so on. what are the differences between them? let's get to know:
1. moisture resistance.
if the capacitor is used in a high humidity environment, the epoxy resin coated capacitor cannot provide reliable humidity protection, that is, use other potting compounds. the external part of the boxed capacitor is sealed with a plastic shell. the sealing effect is far better than that of the epoxy resin encapsulated capacitor, so the boxed capacitor has better moisture resistance.
2. appearance consistency.
the size consistency of the plastic shell of the box capacitor is excellent, and the appearance error of the capacitor is very small. for the epoxy resin coated capacitor, the thickness of the epoxy resin coating cannot be accurately controlled, and the volume of the capacitor has some errors, so the appearance consistency of the capacitor is relatively poor.
3. shock and aging resistance.
because epoxy resin coated film capacitors rely on their solder joints rather than the entire support of the box, any vibration that the container may encounter will be transmitted to the pins. this self generated electrical and mechanical vibration in ac applications may lead to accelerated solder joint aging and affect the life of capacitors.
4. flame retardancy.
many circuits have very high requirements for the flame retardant performance of capacitors. the box structure and resin filled technology can provide high-level flame retardant properties. in contrast, the box capacitor has better flame retardant performance.
5. price comparison.
if only considering the performance, the performance of the box capacitor is far better than that of the epoxy resin coated capacitor. however, compared with the price, the epoxy resin coated capacitor is cheaper and the box capacitor is more expensive. therefore, if the performance requirements for the capacitor are not very high, the epoxy resin coated capacitor is still more cost-effective.
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