Input capacitor of SMPS (IRM 30-12) is burnt

We are using SMPS, IRM 30-12 in our circuit. It is working fine. But, in one circuit the input capacitor (450V,56uF) of the SMPS is burnt. I am attaching a schematic to show which capacitor is burnt.This is not the exact schematic. I want to know the probable reasons due to which the capacitor is burnt (blast)?

The 'dome' on top is a sign that it has overheated and expansion, either of gas or electrolyte, has pushed the safety valve partially open. The indentation in the end of the can is a deliberate weakness so if it does go bang it will be less spectacular and aim away from he board!

The overheating will mostly be from the ripple current flowing through it. Most capacitors in an application like that will eventually succumb but poor quality in manufacture makes some die sooner than others. The ripple current is simply the flow of current in to the device from the rectifiers and out of it again in to the transformer, the losses in the capacitor are converted to heat.

Replace it with one from a reputable manufacturer, make sure it is rated for 105C operation (some are 85C) and check the data sheet for the predicted life expectancy, choosing one with long life obviously. There is often a trade off between longevity and cost with the PSU manufacturer choosing parts that live just a little longer than the guarantee period!

Brian.

Thanks betwixt. I will definitely tell the issue to MEANWELL for their referance. For now, I am replacing the defected capacitor by a new one. I hope the SMPS will work. If some issues arises, I will get back to this forum again. Thanks.