Well a while back I posted about my new 48v system upgrade. http://www.fieldlines.com/story/2008/3/12/32236/4074
This has been great and Im loving it so far. I love the versatility of the Outback equipment as I tend to do weird things and really put things to the test. I basically ripped out the whole system and started over. It was due.
Well, to get on with the story, I had to reconfigure all the charge controllers for 48v (easy, just reprogram) and I ran into a snag with my back up listeroid alternator. http://www.fieldlines.com/story/2008/1/2/231538/0408
When I did such a nice job mounting all the new equipment, I wanted to do the same for the lister rectifier and filter caps. So I built a nice box full of goodies. It held 2 100v filter caps @ 9400uF for the lister and also two 3 phase bridge rectifiers (commercially available discrete component type, made by IR). These are rated for 60A each and one would be used for the axial flux listeroid and the other would be used for a new axial flux turbine Im building for 48v.
This is one of the rectifiers mounted to the inside of the steel box. Each one is bolted to a heat sink that hangs off the exterior of the box.
Here is a view of the box. Pretty sloppy. I had the whole thing ripped apart after it was finished. I was having serious problems with harmonics and voltage problems from the lister. I thought it had to do with the fact I moved up to 48v and the original stator I made was not producing a VOC in the right range for the MX to sweep happily (it used to be fine when I was bucking down to 24v). So I thought oh well, Ill make a new stator for 110vdc and try it that way, after all it would hopefully fix the problem and make things slightly MORE efficient. I also thought I had some bad caps and a bad Airpax DC breaker. I really didnt think all these things were bad and I knew there was something simple that was wrong.
Well, today I was messing with it and I think I solved the problem. I had a bad connection (high resistance) on the 3 phase bridge (possibly internal- it went away when the wire was wiggled). I guess I was unevenly loading the stator, getting bad harmonics caused by high ripple coming through on the DC side. This led to other weird things, like making my 60A breakers trip out at 25A due to high ripple. Well after pulling my hair out and troubleshooting everything, it seems to be fixed and working great. I just have to possibly replace the lister bridge with a higher current rated device because when I was test firing it, I was exceeding the rating.
Thats right, Im now pulling 3500W out of my lister . It bounces around slightly and it was hard to take a pic with 3500w on the display. Im impressed. I think Ill keep things where they are and maybe turn the MX current down a bit. It also would be nice to to some temp measurements on the stator with it running this much power out.