On Friday 08 January 2016 23:44:43 Gene Heskett wrote: > On Thursday 07 January 2016 05:27:09 Gene Heskett wrote: > > On Thursday 07 January 2016 05:07:25 Gene Heskett wrote: > > > On Thursday 07 January 2016 04:50:35 andy pugh wrote: > > > > On 7 January 2016 at 03:32, Gene Heskett <ghesk...@wdtv.com> wrote: > > > > > <http://www.ebay.com/itm/1-set-LY4NJ-12V-DC-Power-Relay-HH64P- > > > > >4P DT -1 > > > > > 4-Pin-10A-250VAC-With-Socket-Base-/120897376163?hash=item1c260 > > > > >b8 fa 3:g > > > > > > > > > >:3~kAAMXQgPhRkf79> > > > > > > > > > > That gives me a 4pdt, > > > > > > > > It doesn't mention being force-guided. > > > > > > That is a relay term I am not familiar with, please define? > > > > I looked it up on wikipedia. It does seem to be a good safety > > feature. Perhaps I should interlock its operation by assuring it is > > switched at no load by turning off a series SSR? I'll see what I can > > cobble up in the hal file. > > As an update, sorta. The parts I ordered are trickling in, the > schottky diodes and tantalum caps have arrived, as has a small 6.3V ct > filament transformer in case I need to encourage a faster turn off the > bleeder, but they aren't much use until the smallish hexfets to drive > relays and SSR's with get here. > > I've changed my mind a bit since I'll have a 4pdt relay. The swinging > contacts of 2 poles will connect both ends of that 51 ohm 200 watt > resistor in series with the line power to the toroids when enabled, > and switch it across the caps for a bleeder when de-energized. The > 3rd set of contacts will parallel the resistor with an SSR, shorting > it when the on timeout has expired. > > This will also, by interrupting that path as the relay opens, remove > any possibility of the resistor being shorted when the relay closes. > The 4th set will feed back to hal, hitting a short timer to make sure > the softstart done SSR is off before it can be re-enabled, enforcing a > 1 or 2 second delay in that event. I haven't located an input pin on > that BoB, but as thats on the P2 connector of a 5i25, there are > several pins available on it yet. > > I also have sourced a 100 foot roll of 26 conductor ribbon, and a bag > of db25 connectors of both genders so I can make cables that don't hit > the wall behind the computer, trying to knock the 5i25 out of its > socket. The cable has arrived, but the connectors are still on a > rowboat someplace... > > Thanks everybody. > > Cheers, Gene Heskett
Continued... Andy's comment about that relay not being force guided, meaning it wouldn't be prevented from a misscue if a contact welded, got me thinking. Which can be entertaining at times... What if I used it essentially for a dry contact, which has its own closure problems, but used the contacts to steer SSR's? 1 set of spdt contacts would swing a 25 volt source thru 2 SSR's control terminals. That pair would be wired to connect the line power to one end of that resistor, while the other end of the resistor would be connected to the toroid power trannies by the 2nd SSR. When they are off, the resistor is isolated, so... The back, nc side of that same spdt section would connect the resistor across the cap bank with 2 more SSR's to serve as a suitable bleeder when the relay was de-energized. The problem with that is that there needs to be a method of turning the SSR's off because the 2nd condition is DC and I've no clue as to the holding current they need to stay on. And I will still be shorting the resistor after a turn on delay to charge the caps to about 90% of full voltage. So how about 2 things: 1. put a small tranny delivering say 6 volts AC in series with the resistor and its shorting SSR to encourage that SSR to turn off when the cap voltage has dropped to 6 volts or less. 2. enforce in hal, 2 delay circuits. An on delay long enough for #1 to have completed its job and the short across the resistor no longer exists thru that pair of SSR's. 3. Time the short enable so its 5 to 10 seconds after the relay has closed, and time the short disable to take place a second or so before the relay is de-energized, so that SSR is off by the time the switch of the resistors position in the circuit takes place. By placing another timedelay in the relay control, with longer time delays than the shorting time delay would enforce disconnecting the short whose timedelay is set for 1 second, so the resistor is switched back into the circuit well before its transferred to dump the caps duty. All proved out on the scope before hooking up the power source of course. That will take one more SSR than I have, but I got those 4 from MPJones fairly fast and relatively cheap, like about $9 USD a copy. Does anyone have an data on how sensitive these SSR's are to a false trigger from dv/dt effects applied to the output terminals? Or do I need to use 2 of these relays with a fraction of a second between them, to assure the line side SSR's have time enough to turn off? At 60Hz thats 8.3333 milliseconds after drive has been removed, and the single relay could be faster than that. All TBD when the relays arrive I guess. They haven't yet. Comments please, and thanks. 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) Genes Web page <http://geneslinuxbox.net:6309/gene> ------------------------------------------------------------------------------ Site24x7 APM Insight: Get Deep Visibility into Application Performance APM + Mobile APM + RUM: Monitor 3 App instances at just $35/Month Monitor end-to-end web transactions and take corrective actions now Troubleshoot faster and improve end-user experience. Signup Now! http://pubads.g.doubleclick.net/gampad/clk?id=267308311&iu=/4140 _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
