SSPA Power Supply - Load Test #6

Success!  Load test #6 is probably the final load test that I'll need to do with this power supply.  

I had no issues with the power supply.  The final protection diodes didn't get much hotter than 95F during this test of 62 amps @ 53 vdc.  In the last test I measured peaks around 180F.  So my junk-pile heat sinks and muffin fans cut their temps about in half.  

This test proved that my fixes for:

• The high temps on the final diodes reduced to 95F which is 50% lower than what they were at, and only 33% of their max temp spec.  Plenty of headroom there now.
• The new contactor and time-delay resolved sporadic initial startup and immediate power down of random supplies (safe mode due to surge).
• Replacement of the 400A shunt with a 150A shunt resolved the low amp reading on the 150A meter (doh!).  I'd read that I should overrate the shunt for safety, that proved to be incorrect.  The ammeter now reads accurately.
• The voltage monitors work in-circuit now.  If voltage is below or above range, the final contactor is forced open.

The only issues I had with this test was that the wires (#14 ga) on the Load Tester elements (and not the power supply being tested) started to get too hot after about 6 minutes of testing.  THAT is acceptable for now :-)   But I'll get some #10 for the future I think.  Maybe even #8 for safety.  If those wires had melted through I'd have had a fire hazard.

Fairly LONG demo video (not real stable if you get sea sick take your meds now LOL).

SSPA Power Supply - Fixes Post Load Test #5

Here are the 'fixes' (or changes) post Load Test #5.  I've added a 200A final contactor so that I can use the voltage monitors to control if we allow power output from the power supply based on voltage being in the proper range.  I can also now delay allowing voltage output until all the supplies have stabilized on initial startup.

I've also added fans and heat sinks for the final dual diodes.

Here's a short video demo of the smoke-test after these changes were made.

And now on to the full load test #6 next.

SSPA Power Supply - Heatsink/Fan for Final Diodes

As mentioned previously on this blog one of the issues noticed during the most recent load testing of this power supply was the final protection diodes got quite hot during a 62 amp load test on a single bank for 4 each 13.5 vdc supplies providing 53 vdc (after the diode drop) in series.  I measured at least 150F on them possibly as high as 180F.  These diodes have a max temp of 150C which equals 302F.  So it wasn't catastrophically hot.  But hot enough to want to try to manage it better than doing nothing.  

I had initially thought I would put some thermal paste under them and bolt them onto the case bottom.  However, since I had some spare parts to do better than that I decided to opt for something a lot more robust.

I had some spare heat sink material and I have a lot of spare computer fans around so I decided to try to mate them up and build to identical heat sink setups for each set of diodes.  Each bank of 4 supplies in this (there are 2 banks) has a dual diode at the end before both banks merge into a single output.  This is to keep their output separated from each bank.


So here are some photo's of what I came up with.  I still have to apply the new thermal paste under them, and make some new cables to run to the output terminals, but I was able to get things migrated around in the case, and the completed heat sink / fan combos built and installed this past weekend.

These fans blow INTO the heat sink instead of sucking out of them.  This forces most of the air UP the fins and out of the case through exhaust fans at the top of the case.

SSPA Power Supply - Final CASE cleanup and prep

Here are some pictures of some of the final prep work on the power supply case along with it's air filters and exhaust fans.

Yeah it's not super pretty but it's plenty functional :-)

Note the strap that retains the supplies firmly in place using a case screw.

Air filters built in the front doors are washable/removable.

Front doors closed position

SSPA Power Supply - Final Diode Cooling

I discovered through some recent load testing that at just a bit above 1/2 max load on the power supply the dual protection diodes I'm using get quite hot, at least 150F degrees.  So to help control that I'm going to cut up a large heat sink I have tomorrow and mount these 200 amp protection diodes on them.  I'm probably also going to add fans to the heat sinks as well.

Here are some pictures. 

SSPA Power Supply - Lessons from Load Testing

• Creating a DC load testing device is pretty simple should you ever need to do this.  It was also very helpful to point out some short comings in my DC power supply design.
• Use a cheap 10 gallon (or more) METAL barrel.  
• Drill 1"+ holes in the barrel to accommodate the amount of "AC" water heating elements you intend to use. (I used a step-bit to get this very tight, in order to avoid leakage)
• Clean the metal around the whole at least 1/2" with a wire brush or sand paper.
• Use high temp silicon like (RTV "Red" which is good to 650F, or SIL-100-GP which is good to 450F) to help seal inside and out of the hole you drilled.
• Use high temp thread sealer between the water heater element and the retaining nut.
• Use Stainless Steel 1" NPS nuts (probably will cost more than the heating elements!) mine where $7.50 for the nuts, and the heating elements were $5.79.
• Heating elements I used are 120v/1500w @ 10 ohms.  Which makes the calculations fairly simple.  It's basically just a 10 ohm resistor.  two in parallel = 5 ohm, three = 3.33 ohm, four = 2.5 Ohm, six = 1.6 Ohm etc...  Once you know the ohms of the heating elements you're using it's just (ohm/#ele)=resulting ohm.  Then using ohm's law you can calculate the amps @ volts you'll be pulling through it.
• WARNING...Be sure to use a wire-gauge that can handle the amps you've calculated!  Or you've basically created a fire-starter.
• That's basically it.  Wire the heating elements in parallel and fill the barrel with water, connect power and test.  BE SURE TO Monitor the water temp as well as the heating elements and wires used.
• WARNING...if you don't understand what I'm talking about, don't attempt to do this!
• I discovered that at 33 amps I saw virtually no stress on any components I was using.  It wasn't until I doubled that by adding 6 more heating elements to the load and drew 62 amps @ 53vdc that I noticed my final protection diodes were hot and needed to be heat-sinked and possibly a small fan added.  (more to come on that in the next set of tests).
• I discovered at 62 amps at TURN-ON time (instant load on the power supply when 240vac was applied) that sometimes individual 13.5vdc power supplies would startup and immediately go into 'safe-mode' and shut back down.  That's a safety feature built into the dps-1200fb power supplies.  
• This was happening because I have no disconnect-relay or 'contactor' device at the final of the power supply.  So any load attached at start up would cause an instant surge before the bank of supplies had a chance to stabilize, and they would go into safe-mode.  Which basically means I would have to power it all down and try again and hope that the next time they'd start up (and they usually would).
• This isn't acceptable behavior.
• I also already have the ability to 'act' if a bank of supplies isn't putting out the voltage I expect.  It's already built into this system, but because I have no final relay/contactor to energize I can't really 'act'.  Even tho I have the monitor and relay in place to do so.
• Resolution of the last two items in this list, I've found and ordered a 12vdc coil, 220 Amp @ 55vdc 'Contactor'.  below are some pix of it.  I found this one on Ebay "New" for about $43.00.  I'll add a 10 second startup timer which will fire at power on time.  After 10 seconds the power supplies should be stable enough for a good sized surge.
• I can also wire this same contactor up to the bank voltage monitors so that if something fails and I don't have the voltage I expect output power will not be available because I can force this contactor to go 'open'.

SSPA Power Supply - Load Test #5

The first attempt failed to start all 4 supplies in bank 0.

This afternoon I drilled and filed out the new holes for the 6 addition water heating elements being added to double the load test on the power supply from 33 amps to 62 amps.  And also added both a water inlet valve and outlet value (3/4").  This will allow for water flow into and out of the tank.  Cold water comes in the bottom and hot water drains out the top.

For this test I didn't run water flow through it.  I simply filled the can up and ran the test since it was basically a short 'smoke test'.

I ran into two small issues this time around.    I was only running "bank 0" so 4 each 13.5vdc supplies in series.  Instead of bank 0 and bank 1 which would be 8 supplies.  The idea was to put a good strain on the system.

So what I found is that the 'final' dual diode warms up pretty good.  I measured about 150F on it which is too high. I need to heat sink those final diodes and possibly even add a fan, or TEC to them to really keep them cool when there's load.  This test was just between 1/2 and a 3/4 load test.  75 amps would = 3/4 and this was drawing 62 amps.  

These diodes are rated for 150v @ 100 amps.  The power supply bank that feeds them is capable of 100 amps.  However I am running two wires from the positive side out which split the load one wire goes to one of the dual diodes sides the other wire to other side.  I suspect this is sharing the load somewhat but I haven't tested that.  I might not be too :-)  Won't know for sure until I test it out next time.


I also found that the protection diodes on the power supplies where about 90F.  This could just be heating up from the power supply they're connected to...and not because they're taking any sort of load (because they shouldn't be).

I found that with this much load on the system instantly at start up...all of the power supplies didn't want to come up.  The first attempt I had about 26v the second was 53v the third try was 40v.  So what's happening is that these power supplies don't like having that heavy load placed on them instantly at start up and they'll power down (what appeared to be randomly).

This didn't happen when I was pulling 33 amps.  This is the first I've seen it happen, so the load test process is helping me find things I need to address.

I have been thinking for a while that I need a FINAL relay that can be controlled from a few places.  Like when the output voltage isn't where it should be for one of the banks I would want to OPEN the FINAL RELAY.  

But also to solve this 'instant load at startup' instability (which won't actually happen when I'm using this with the SSPA anyway, but I'm just trying to make this be robust and survive me being stupid in the future.  So to solve that I just need to add a timer to control a final relay and tell it to wait 10 seconds while the supplies startup and stabilize, and then close the relay and draw power as needed.  

I've thought I needed something like that for a while, but I've been putting it off.  

I'm pretty sure I know the relay I want to use, but I need to find one for sale.  It may take a while to find one that can be controlled by 12vdc and be able to handle 54vdc @ 200 amps :-)  But I'm sure I can find one.

SSPA Power Supply - Load Test #5 (coming soon)

Today I ordered 6 more 120v / 1500 watt / 10 ohm water heater elements to add to my load-test-barrel :-)  That'll bring the amperage up to about 64-66 amps or so.  Should be a good solid test for this 200 amp capable power supply.  

The heating elements are fairly cheap at around $5.80 each.  So no big deal there.  But the 1" NPS Stainless Steel nutz that go inside the barrel to mount them are almost $8.00 each.  (I'd try a different nut if I could find one, if I was doing this over again, or if I built another like this, but fortunately I won't have to build another one like this cause this one is all mine :-)

I *MAY* purchase another 6 elements and nuts sometime to get this load tester up to 100 amp capable.  But I don't think I'd go much higher.

So...in about a week or so I should have these 6 I ordered today added into the load test barrel and present a test here on the blog.

66 amps should be enough to press these 8 supplies hard enough so that the fans will come on and the system will generate some heat I think.  (besides the water in the water in the barrel).  If not, then I'll have no more worries about this supplies ability to be pressed VERY hard.  So far at 33 amps it's not even feeling it.  Not at all.  Things are about the same was when it's all on idle!  Seriously.  That's pretty impressive to me.

So, more to come when the next parts come in.  

After this next round of tests, I'll be ready to start getting the RF amplifier parts ordered and built ready to be used with this power supply.

UPDATE:

Parts all arrived together yesterday, I'll be upgrading the Load Tester later today 9/22.

SSPA Power Supply - Load Test #4

Ran the first long term test at load today.  33 amps @ 53 vdc - I was running both banks for this test.  

I KNOW this is a bazaar looking way to test a DC power supply.  I'm not sure I've ever seen anything like it before.  But it's similar to a dummy-load for RF where there's a resistor in a gallon of oil I guess.

Except that these are 120v AC 1500 watt, 10 Ohm Heating elements (6 each) fitted into the sides of a 10 gallon barrel of water and wired all in parallel.  Which results in about 1.6 Ohms of resistance @ 53 vdc.

This test started with 76 F degree water.  I ran the test until the temperature went up about 10 F degrees so about 86 F.

The 8 DSP-1200fb 13.5vdc power supplies running on 240v AC only reached about 76-80F degrees, and the fans barely came of idle during the entire 6-7 minute test.

Everything ran just fine.  

The only thing that didn't work as expected is the Ammeter on the face plate of the power supply controls.  It was reading about 15 amps.  While the Fluke Clamp meter was indicating 33 amps.  So I'll have to figure out what's happening with that.

Here's a Video of this test session.

The next test I do will only running a single bank of 4 each 13.5 vdc supplies instead of the two banks of 8 total I ran today.  That should stress the 4 supplies a bit harder, I think enough to run their fans off idle.

To leak-proof I used "SIL 100 GP" silicone which is good to temp's of 450 F degrees!  WAY overkill, but I had a 1/4 tube of this left over from some other project.  I also used high-temp thread sealer for the 1" NPS Stainless Steel nuts that go inside the tank to retain the heating elements.  I used a heating element socket (they're cheap and the best way to tighten them down).  And a pair of vice grips on the inside holding the nut.    This was all about as simple as can be.  

The hardest part of building this load tester was just cutting the 1"+ holes for the heating elements with a cheap set of 'step-bits'.  And even that wasn't hard really.  

I may order 12 more heating elements now that I've seen that 6 of them barely heats the water 10 degrees in 6-7 minutes.  With a total of 18 heating elements I should be able to get to 100 amps being drawn.  That's where I want to be ultimately for testing this power supply.  10 Ohms / 6 elements = 1.6 Ohms.  So 10 Ohms / 18 elements = 0.55 Ohms.  Which would be close to 100 amps being drawn.

SSPA Power Supply - Load Test #3

The new 10 Gallon water tight steel barrel is here, as are my 6 each 120vac/1500w/10Ohm water heater elements and some Stainless Steel 1" NPS with o-ring seals.  I bought a cheap set of 'step-drill bits' that step from 1/8" to 1 3/8".

I semi-randomly cut 6 holes in my new water tight barrel and inserted the water heater elements and attached the 1" NPS nuts and o-rings.

This will end up being my high-amperage load-tester.  There's plenty of space for 12 more heater elements if I wanted to pull 100 Amps @ 53vdc with this setup it would take a total of 18 water heater elements.

So once that's been done, the next step is to add a INLET and OUTLET from the 'tank' (barrel) so that I can flush cold water though it while it's in use.  If I didn't care that I 'wasted' water I could just just use garden hose and bulk-head fittings and run water out of the 'tap' through the tank and out into the garden or something.

But what I'm going to do is locate a small car radiator, and 12vdc fan and a water DC water pump and just recirculate the water I think.

My first test will probably be the garden-hose method :-)  Because it's quick and simple and should help me locate any leak issues.

Here's some of the construction pictures.  So far the only expensive bits where the 10 Gallon Barrel (I paid $25 shipping :( ) and the SS nuts which were $45.00.  I could really have just used any 1" NPS nut but these were about as perfect as I could find.  6 each heating elements costs $30.00 (amazon prime makes shipping free).  So this'll test up to about 33 amps @ 53 vdc as I've already discovered.  $50.00 more in heating elements and 12 more holes in my barrel will get me right up to 100 amps.  Which is the max that one "bank" of 4 supplies in series will provide.

SSPA Power Supply - Load Test #2

Today I connected 5 each (1500w/120v/10 Ohm) water heater elements (costing $5.00 each) in parallel which ended up with between 1.9 and 2 Ohm's of resistance.  

I was able to witness the voltage drop over the final Diodes from 53.9v to 53v.  Which is very close to what the datasheet predicted for these dual diodes.

I ran both bank(1) and bank(2) for this test today.

The result was 26.5 amps pulled with a 0.9vdc drop after the final protection diodes voltage of 53.0v.

Based on the how the paralleled heating elements ohm'd at 1.9 Ohms the prediction was 27.89 amps @ 53v for 1478 watts total.  



So prediction math vs. reality was off about 1.49 amp but at least the supply can draw nearly 30 amps using this test.  I have a 6th heating element I could connect as well.   That would theoretically end up at 1.6 Ohms and 33.1 amps drawn. 

Currently the problem I have is that I can't run this test and let things remain at-load for more than about 10 seconds.  I don't want these heating elements to overheat.  And after just 10 seconds they are to hot to touch.  

I have a 10 gallon steel drum that I'm going to tap for these six heating elements.  Then I'll fill it with water.  That should allow for several minutes of testing.

Apparently it would take abut 167 minutes or 2 Hours and 47 Minutes to 'boil' 10 gallons of water if Efficiency = 95% and the starting water temp was 50F degrees.  So I'll probably add ICE to the water and get good and cold before I start any real testing.  Although if the starting water temp was 80F degrees it would still take 136 Minutes to boil or 2 Hours and 16 Minutes.

The idea is to not let the water get anywhere near that hot.  Testing once that's working will be one minute ON on minute off (to simulate something like JT65A load's).

For reference 30 amps at 53 vdc is enough to drive a single BLF188XR to full power output.

UPDATE

I added the 6th heating element and indeed the Ohm's dropped to 1.6 Ohms when tested it yielded a draw of 32.4 amps.

My 10 Gallon Steel barrel will be here tomorrow, and I'll try to figure out how I'm gonna mount 6 heating elements into it :-)  More on that another soon I hope.

SSPA Power Supply - 50 Vdc Monitor

Available on Ebay

Because this 54 VDC supply is based on a bank of four each 13.5 vdc supplies all in series, if one of them should fail while I'm using it, I want the system to react automatically.  It's fairly simple to just monitor for a particular voltage and if it changes out of a small range up or down then we know something is 'wonky' and we need to react.  

I looked into creating my own circuit for this, and decided that I simply didn't want to do it myself, so I looked around for options and found a place in China who sells just what I wanted both on Amazon, and on Ebay.

I decided to give them a try about 2 weeks ago, and I ordered two of them.  They cost $33 USD each.  Kinda pricey, for what it is, but these devices look like they'll fit nicely, and then also include a time range so if there's just a brief voltage change a reaction can be delayed from 1-15 seconds.  So for example if set to 15 seconds, and there's a voltage change for 3 seconds but then it goes back into the OK range then nothing happens.  Like a buffer.

So for my system I'm planning to try to tie this into the soft-start relay portion.  Basically if voltage isn't between 46 and 56 vdc I want the whole system to shut down (at least for now) and that'll happen by wiring this voltage monitor's relay terminals in to the primary relays somehow.  (yet to be determined)

Here's a little video demo of this device functioning.

SSPA Power Supply - Load Testing - Part 1

So now that I've built this big power supply (50 vdc @ 200 amps) I want to test it with some load on it.  At first I thought I could try using several car headlamps in series, I tried that, but the first one in the string kept burning out, and so I stopped trying that.  It would get expensive to try that for long.  (Although I think with enough of them in series it would probably work).

I gave up on that idea.

Then I came across a website that talked about dumping excess DC from Solar and Wind farms to AC hot water heating elements.  Turns out these elements are just huge resistors.  So I went and bought one for $9 and change from Lowes.  The one I bought was for 120v AC @ 1500 watts.  It is 9.1 Ohms.

So using some simple calculations this is approximately what I should see from using this heating element as a load on my power supply.

320.4 Watts
54 VDC (this is what the my supply is set for currently)
5.934 Amps 
9.1 Ohms

Since these heating element can't survive out of water or cooling more than a few seconds (normally) I only tested this for less than 10 seconds.  (longer tests will be coming soon).

My Fluke meter measured about 5.7 amps in the real world.  So this is roughly about 310 to 320 watts being drawn on a 10.8 kilowatt (54vdc @ 200amps) capable power supply.

Not much of a load test really.  But it's a start.

Since these heating elements are the cheapest 1500 watt 9 ohm resistor available (I'm pretty sure) this is probably what I'll continue to use to load test.  Although I'll probably buy 10 of them so I can pull about 56 amps on the supply.

I want to be able to pull at least 50 amps @ 54 vdc for 1 full minute.  Then pause 1 min, then pull again, then pause on-off-on over and over for a while.

That's the idea anyway.

SSPA Power Supply - First Run all 8 Supplies - OK

Today I completed adding the protection diodes in this whole supply.  One for each of the 8 power supplies of 2 banks of 50 vdc.  And then one for each Positive lead coming out of each bank over to the final distribution block.

Today was also the first time I've powered up all 8 power supplies at the same time and had them providing output to a single distribution block.  

I haven't seen any strange behavior with any of this yet.  (Knock on wood).

Here's a few pictures (click on them to zoom):

Here's a short video of this first smoke test with all the supplies running at the same time.

Again this is two banks of 50 vdc running in parallel.  Each bank has 4 supplies set to 13.5 vdc and they're running in series to provide 54 vdc out total.  

I boosted the output on them recently to overcome for diode voltage drop (if there is any, there should be when the system is at higher loads).  We'll see and I'll report on that when I have a way to stress test / load test this system.

SSPA Power Supply - Voltage increase Mod

As mentioned in my last post here I will be wanting to increase the voltage output of each dps-1200fb power supply in this new system from 12.5 to 13.5.  The result is that the series output of four of these supplies will be 54 vdc instead of 50.   the dps-1200fb has a protection that will shut the supply down at 12.8+ vdc unless this mod is completed.

I'm doing this to overcome the diode drop of the protection diodes I'm installing this weekend.  When at full load I want this to result in 50 vdc output.

There is an expected sum total diode drop of almost 4 vdc. (if my calculations are correct).  If not I'll just do this mod and tune the supplies to the output required to accomplish 50 vdc at max load.

I'm replacing the oem pot shown in the pictures below with a Panasonic 2K Ohm pot p/n: P3Y202CT-ND available here.

WARNING: 

If you decide to attempt to do this...be sure to use a fair amount of flux.  Make sure that you have the two pads that are on the same side heated evenly before you attempt to lift the pot or you will probably tear the solder pad and it's trace off of the circuit board!

You have been warned!  Take your time, and make sure you follow this advice.

Partially removed

removed

Installed - New

Installed

(Left is the new one, right is the old one)

SSPA Power Supply - Protection Diodes

I've seen a few (probably real smart) folks out on the web running power supplies in series like I am.  Some of them are using diodes bridged between the positive and negative on EACH power supply in the series.  

The idea is to protect the other supplies in the series-chain if one of them should short or fail.  At least that's how I understand it.  Honestly, in my humble (unknowing) opinion this is probably going a bit far for protection.  BUT then again if it prevents something catastrophic like a fire...I'm all for it :-)

If you've been following this project and many of my other ones I try to error on the side of safety and over-sizing.  :-)  I just don't like that 'pending doom' feeling every time I strenuously exercise my equipment. 

So...I'm going try to add diodes on each supply in the series of each 'bank'.  As you may remember there are four 12.5 vdc supplies in series in each 50 vdc 'bank' within this system.  Then there are two 50 vdc 'banks' run in parallel for a total of 200 amps @ 50 vdc.

Each of my 12.5 vdc supplies is capable of 100 amps.  So I have 100 amp diodes.  (it's NOT LIKELY that I would ever run this system at maximum as long as the zombie invasion never happens.  SO this is probably safe.  SIZE is an issue with diodes this big.  So 100 amp are the ones I chose.  

This is one I'm going to try to span the positive and negative of each supply.  It's a Vishay p/n: VS-100BGQ100. 100 (If) amp 100 volt with a Vf of 0.82 @ (If).

Then to separate the two 'banks' of 50 vdc I got two of these.  IXYS p/n: DSS2X101-015A.  100 (If) amp 150 volt with a Vf of 0.77 @ (If).

So I think that because the diodes in the series supplies would 'sum' their respective Vf's at Max If that I'll need to adjust the Po of each supply (with a mod, discussed below).  0.82 (Vf) vdc * 4 (supplies) = 3.28 vdc dropped at max current out.  + 0.77 vdc at the final for a total = 4.05 vdc.

That would mean that I'd have to run this system at 54.05 vdc at idle so that at Max load output it would only drop to 50.0 vdc.  (and that's likely being generous assuming that the power supplies can really maintain regulation at their set output at max load.

OK lets say I'm OK with that.  So in order to even get close to this...I'll have to go back into each power supply and modify a potentiometer that's in there with a 2k ohm pot.  I have those on hand and was thinking I would probably do this anyway.  

Once the pots are all changed out then instead of running 12.5 or (max unmodified) of 12.7 vdc per supply, I would be able to run 13.7 vdc.  13.7 * 4 = 54.8 vdc!

That's more than enough to overcome the voltage drop caused by all these protection diodes.  

So...that's probably the route I'm gonna go.  I have all the parts I need to do this.  I just need to do it.  So I'll be working on accomplishing that over this coming weekend, and I'll report on the results and provide pictures along the way.

I swear I'm pretty close to be all done with this power supply.  LOL just a few more things to do after this.  (honest)

SSPA Power Supply - CORCOM P/N 200DFC6-P 200AMP 1000nF FEEDTHROUGH CAPACITOR CLASS Y4

New Corcom 200DFC6-P arrived and installed.  I got this on Ebay for $75.  Not cheap, but they are $165 new if you can find them, so pretty decent savings there.  Here's the datasheet on this device.  Insertion loss is somewhere between 50-90 db at 50 MHz.  Probably very close to -70db down.

Because I'm using switch mode power supplies in this system I'm trying to filter any noise entering and leaving this jumbo power supply.

(Click image to zoom)

In the rear of the case (top almost center) you can see the new 200 Amp 130v "Feedthrough Capacitor".  That's 2 AWG feeding it from the 400 amp (2x over rated on purpose) Ammeter Shunt.  4 AWG everywhere else on the DC stuff inside this case.

I don't really know for certain if this will be enough to keep the power coming out of this system clean, but I suspect it will be pretty good.  We'll know later this fall when the RF amp that uses this power supply is on the air producing RF, and putting a load on this power supply.  Until I can get a load on it, I can't really tell for sure how clean it'll be.

At least on Receive I should be very good.  Since the RF amp and the power supply are at minimal load at that point.