Just curious. Did you hook a temp probe on the capacitor and determine the temperature the caps are subjected to while running the circuit? John --- On Wed, 7/14/10, Roger Weichert wrote: > From: Roger Weichert > Subject: [EE] Bulging Electrolytics > To: "Microcontroller discussion list - Public." > Date: Wednesday, July 14, 2010, 6:57 PM > Hi guys, > = > I've been going to ask for a while about possible causes > for the failure of = > some 10,000uF 35v electros that are used in a basic power > supply for a = > pulsation controller. > = > There are 7 of them in parallel and on a couple of > occasions I have seen = > where nearly all have swollen and split their tops and > leaked and dried out. = > In fact they rattle quite noticeably when you shake them. > = > >From my understanding I thought that electros only > burst if they are fed = > with AC or if their voltage rating is exceeded. > = > In both cases the rectifiers were ok and on fitting new > caps the supplies = > worked fine. > = > The originals are rated at 35 volts and even unloaded have > a maximum of 15 = > volts applied. The 240v input would have to more than > double to get the = > secondries anywhere near 35v !!! > = > The originals were also only rated at 85 degrees, and I've > fitted 105 degree = > replacements, but while excessive temperature can dry them > out, I wouldn't = > have thought it would cause this problem. > = > I've uploaded an image at=A0 =A0 http://imagebin.ca/view/HX_1Ati.html > = > Any thoughts please. > = > Regards,=A0=A0=A0Roger = > = > -- = > http://www.piclist.com PIC/SX FAQ & list archive > View/change your membership options at > http://mailman.mit.edu/mailman/listinfo/piclist > = = -- = http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist