On 3 May 2016 at 10:41, Nicklas Karlsson <nicklas.karlsso...@gmail.com> wrote: > In other words i/C should be less than maximum allowed du/dt.
I am not sure how to determine the i for this calculation. I guess I can find the dv/dt from the component numbers on this page: http://www.instructables.com/id/The-inner-workings-of-Counterfeit-FOTEK-SSRs/ The servo drives have so far been limited to 4A, but whether that translates to 4A at the input to the rectifier I am not sure. Section 6 on page C-343 here: https://www.omron.com/ecb/products/pdf/precautions_ssr.pdf shows a square-wave with zero time at 0 current. But I don't understand how that is possible with a sinusoidal input voltage. Surely the current is zero for all the period of the cycle where the input voltage is less than the capacitor voltage? I wonder whether I would be better with DC-rated SSRs on the DC side of the rectifier? > Problem might also be because you discharge a voltage into a capacitor and > get a very large inrush current but this require a different solution. One of the failed SSRs is meant to be that solution, it is used to bypass a current-limiting resistor once the bus voltage reaches 300V. In case it helps, this is the input circuit. https://imagebin.ca/v/2fs1b7szpsMy The SSRs are controlled by LinuxCNC individually. (actually, the first SSR is controlled by a small mechanical force-guided relay which also switches-in a discharge resistor when the PSU is turned off, but I don't think that circuit is relevant to the SSR circuit) -- atp "A motorcycle is a bicycle with a pandemonium attachment and is designed for the especial use of mechanical geniuses, daredevils and lunatics." — George Fitch, Atlanta Constitution Newspaper, 1916 ------------------------------------------------------------------------------ Find and fix application performance issues faster with Applications Manager Applications Manager provides deep performance insights into multiple tiers of your business applications. It resolves application problems quickly and reduces your MTTR. Get your free trial! https://ad.doubleclick.net/ddm/clk/302982198;130105516;z _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
