I would not bother buying used caps. (Not sure you were) Power electrolytics have a rated life listed in hours and you would be amazed at how few hours some caps are rated.
I would only buy new caps or NOS (New old stock) caps. If they have been sitting on a shelf for a long time, like years, some caps have a procedure you are suppose to follow to condition them for use and it can get pretty involved. So new caps are best. Anything you do with components will be cheap compared to buying new or repaired parts from Fanuc. Dave On 7/16/2014 10:29 PM, Jon Elson wrote: > On 07/16/2014 02:16 PM, Leonardo Marsaglia wrote: >> Well. I took up one of the capacitors and the label says the following: >> >> HCGFA >> 1800 MFD 450 VDC >> SURGE 500 VDC >> POSITIVE + >> >> Here is an ebay link that shows the actual capacitor that I have. >> http://www.ebay.es/itm/HCGFA-Capacitor-1800-MFD-450-VDC-Surge-500-VDC-Used-/120838813902 >> >> There are several models on Digikey that have the same capacitance and >> voltage ratings, but I don't know if theres anything else to check. > Make sure the spacing between terminals is the same, and it > should fit fine. >> Visually inspecting the caps, they look ok, they don't seem to be swollen >> or anything, but I guess that doesn't tell anything. >> >> > Sometimes a deteriorated cap is plainly obvious, sometimes there > is no visible sign at all. You could charge the cap to some > voltage and > observe the rate at which it drains. For 1800 uF, with a 10 > K resistor, > the voltage should fall at an exponential rate such that it > reaches > 36% of the initial value in one time constant. One time > constant > would be .0018F * 10K Ohms = 18 seconds. So, if you charged > it to 10 V, in 18 seconds it should fall to 3.6 V. If it > falls to > zero in a couple seconds, that is a clear indication the cap is > dead! Sometimes, they can develop high internal series > resistance, > so another test is to charge it to 10 V or so, and then > short the > cap with a bit of wire. If there is no spark at all, it > would indicate > high series resistance. > > Jon > > ------------------------------------------------------------------------------ > Want fast and easy access to all the code in your enterprise? Index and > search up to 200,000 lines of code with a free copy of Black Duck > Code Sight - the same software that powers the world's largest code > search on Ohloh, the Black Duck Open Hub! Try it now. > http://p.sf.net/sfu/bds > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users ------------------------------------------------------------------------------ Want fast and easy access to all the code in your enterprise? Index and search up to 200,000 lines of code with a free copy of Black Duck Code Sight - the same software that powers the world's largest code search on Ohloh, the Black Duck Open Hub! Try it now. http://p.sf.net/sfu/bds _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
