On Friday, May 25, 2012 10:19:59 PM Jon Elson did opine: > gene heskett wrote: > > However, if the problem is related to the spikes on the line caused by > > slow recovery characteristics of the diodes in this kits high voltage > > DC supply, those spikes will be attenuated by the poor high frequency > > response of the transformers. They won't look as if they are big > > enough to be a problem so most would ignore them. > > Well, this is possible. the generated phase has a much higher impedance > than the supplied > single-phase mains. If this IS the problem, a few big caps of the phase > correction sort > across all the L-L terminals might absorb enough of this to keep the > protection circuits > from tripping. But, of course, the presumably modest Diesel generator > would also have > a somewhat higher impedance, and the drive ran fine on that.
Something I neglected to consider when I wrote the above story. > So, I'm > still thinking this > is more likely to be a simple phase imbalance problem than a spike > problem. But, > without knowing what sort of input protection gear this system has, it > is impossible > to know. On the other hand, if the input module uses SCR phase-angle > regulation, > then phase imbalances would cause a HUGE problem as they screw up the > commutation angles of the SCRs, and could easily overvolt the DC bus. I think that is the more likely situation, although that would seem to require some sort of interphase linkage, possibly timer related to throw it that far off. I didn't dl the link to the manual, figuring if there was proprietary stuff in the thing, it probably would have the piece we would like to study inside a blank box on the schematic. I have had to deal with that on many occasions, even going so far as to carve the epoxy or baked on tar away to see what was in a couple of those 'bricks', only to find the part numbers had been carved off before it was encapsulated. Not exactly helpful when the thing is 6 years old & they crawled under a rock 3 years back. But as the one who has to fix the stuff, makers who do their stuff like that usually get added to my "we won't buy any more of that makers products" list. Often, we found that with diligent searching now that we have the internet, we can buy that feature in a device with a whole grocery list of stuff that turns out to be quite useful in the battle for eyeballs, in one case with a better warranty and support system than the big boys were bragging about, and for 30% of the Big Boys price. And I think they are still around. They _gave_ us the software tools that allowed us to be creative with their product, something that Grass Valley wanted a 5 figure price per seat at the table for their stuff. You can guess who gets the first phone call when we need something else they might make. > Jon > > ------------------------------------------------------------------------ > ------ Live Security Virtual Conference > Exclusive live event will cover all the ways today's security and > threat landscape has changed and how IT managers can respond. > Discussions will include endpoint security, mobile security and the > latest in malware threats. > http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/ > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users Cheers, Gene -- "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) My web page: <http://coyoteden.dyndns-free.com:85/gene> If a train station is a place where a train stops, what's a workstation? ------------------------------------------------------------------------------ Live Security Virtual Conference Exclusive live event will cover all the ways today's security and threat landscape has changed and how IT managers can respond. Discussions will include endpoint security, mobile security and the latest in malware threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/ _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
