gunrunnerjohn posted:Adrian! posted:After looking at it in drawing form I think the grown up way is to have a psx-ac on each brick then do the power combining after. That way the current limit of the psx-ac doesn’t come into it and we can expand to as much current as wanted.....
I'd actually ask the question about how the PSX-AC handles being paralleled with another, that could be an interesting interaction.
Hi All,
Okay I finally have an satisfactory answer to this (I was wondering about it too). We added a lot of connections exactly like the one in this drawing throughout our club layout to get more current. We did some with 2 branches and some with 3 branches but the result is the same...
It works well, but not perfectly. The PSX-ACs do not go crazy or anything, but small mismatches in the PSX-AC do imbalance the draw on each PH180. For example if you draw 10 amps from the above, you would expect each PH180 to give equal current (like 5A and 5A) but in reality because of small mismatches you'll find it's more like (6A and 4A). When you get to triple stacking it gets more diverse (we saw 5A, 3A, and 2A on a 3 branch system). So yes you can do this to get more current, but it doesn't get you to "n-times" the capacity of one brick because one PSX-AC will trip before the others as the current isn't drawn equally. Once the first PSX-AC trips the load jumps up on the remaining ones so they trip. You can see this on the oscilloscope but it all happens so fast in realtime it just feels like 1 circuit interrupter acting together.
We bought 7 new PH180 bricks and 7 new PSX-ACs, and we ended up trying different combinations on the bench to see which combo of parts minimized mismatch. In the worst case we saw like 3A and 7A, while we got it as good at 5.5A and 4.5A with some swapping. So if done right you can get like 17A capacity out of 2 of these in parallel (ideally 20A). On the 3 branch one it got us more like 24A than 30A, so I suspect as we get to larger and larger numbers of parallel paths, it's diminishing returns.
Anyways hope this is useful info for others!
