On Monday 07 December 2015 05:29:15 andy pugh wrote: > On 7 December 2015 at 03:25, Gene Heskett <[email protected]> wrote: > > About 3 or 4 of those, wired in parallel, would also serve as an > > inrush limiter when I turn on the power supply for my G0704 mill. > > http://uk.rs-online.com/web/p/thermistors/2118030/ > > (And similar) > > But finding one that is big enough might be harder. > > When I built the PSU for my milling machine I put a 100W resistor on > the inlet line, with a relay to bypass it after a fixed time (using a > 555 timer). > > By a coincidence, I was building a PSU for my lathe this weekend, and > I have taken a different approach. The drives are Mesa 8i20, and these > report bus voltage back to HAL. So the new PSU has the internal relays > controlled by HAL. > One SSR turns the power on, then another will be closed by HAL when > the bus voltage has reached a threshold, and at that point the > ...enable... pins will be toggled. > The same chunk of HAL will be set up so that the PSU can't be turned > on unless the bus voltage is <2V. This is to prevent arcing/welding of > the contacts of a third (mechanical) relay that connects a crowbar > resistor across the caps when the power goes off.
That was the reason for the night light lamp cobbled into mine, but its since burned out, probably from some rigid tapping as Jon's WM servo is a full 4 quadrant amplifier, lighting up that lamp well past its normal brightness as it reverses the spindle motor. Those caps under the pcb buss bars can hold a surprising charge for an hour or more. Cheers, Gene Heskett -- "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) Some mill pix are at: Genes Web page <http://geneslinuxbox.net:6309/gene/GO704-pix> ------------------------------------------------------------------------------ Go from Idea to Many App Stores Faster with Intel(R) XDK Give your users amazing mobile app experiences with Intel(R) XDK. Use one codebase in this all-in-one HTML5 development environment. Design, debug & build mobile apps & 2D/3D high-impact games for multiple OSs. http://pubads.g.doubleclick.net/gampad/clk?id=254741911&iu=/4140 _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
