I'm putting together a rig to "reform" capacitors of the 63V persuasion. The idea is to take the voltage up to the rated voltage of the capacitor at a low charging current. My goal is to do it inexpensively.
I plan on getting one of these adjustable dc out boards based on the TL783 from audiowind on ebay. I have attached a link to the cut sheet. I have an adjustable AC supply (90-140VAC) that is also an isolation transformer to feed it. I believe I can easily use this board to get up to 100VDC, if necessary. I would put this particular 63V capacitor to be reformed in series with a 1K/10W resistor to limit the current within spec of the board, take the cap up to the 63V, and leave for a few hours. Does this sound like a good idea?
I also want to test capacitors from questionable sources to ensure they are, in fact, of the stated voltage. Let's say they are not. What happens to a capacitor as the voltage exceeds its rating, does it gradually get hot before exploding? What is the best way to ensure that a capacitor is not being misrepresented as to its stated voltage (other than purchasing from a "reputable" source)? I would much rather have this rig get fried (though it does seem to have some protection properties), than a high priced amp I've installed the caps in.
Audiowind SP-4
http://www.audiowind.com/pdf/sp-4.pdf
I plan on getting one of these adjustable dc out boards based on the TL783 from audiowind on ebay. I have attached a link to the cut sheet. I have an adjustable AC supply (90-140VAC) that is also an isolation transformer to feed it. I believe I can easily use this board to get up to 100VDC, if necessary. I would put this particular 63V capacitor to be reformed in series with a 1K/10W resistor to limit the current within spec of the board, take the cap up to the 63V, and leave for a few hours. Does this sound like a good idea?
I also want to test capacitors from questionable sources to ensure they are, in fact, of the stated voltage. Let's say they are not. What happens to a capacitor as the voltage exceeds its rating, does it gradually get hot before exploding? What is the best way to ensure that a capacitor is not being misrepresented as to its stated voltage (other than purchasing from a "reputable" source)? I would much rather have this rig get fried (though it does seem to have some protection properties), than a high priced amp I've installed the caps in.
Audiowind SP-4
http://www.audiowind.com/pdf/sp-4.pdf
I once bought a bunch of caps marked 2200uF 35V. When I got home, I wondered why it had 2 layers of shrink wrapping. Took the outer layer off and they were 25V caps.
I would think that once the voltage rating is exceeded, there would be an increase in leakage current. Go higher and it starts to heat up. Higher still then it blows up.
I would think that once the voltage rating is exceeded, there would be an increase in leakage current. Go higher and it starts to heat up. Higher still then it blows up.
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