Friday, October 21, 2016

SSPA Water Cooler - Some Assembly Required

I have most of what I need for this area of the new amp now.  I still need to get a few 1/2" tee's.  I got some 3/8" tee's but they're way too small even for the 3/8" ID hose.  Not sure what they were measuring when they made those!    

So I'll have to make a trip to Lowe's or Menards this weekend.  I also want to try using Flex Seal in my 5-Gallon Reservoir.  The Tank is carbon steel, and isn't lined with anything that I can see.  I'm not going to risk it.  I already know if there's no coating on it, the first time I run water through it, there'll be rust.  And then it's almost too late to continue trying to use it.  So I'm going to try sealing it, and hope that Flex Seal can handle the intended use I have for it.  

These pictures aren't really showing anything in final assembly yet.  But may give some idea as to how this'll start to go together.

Tuesday, October 18, 2016

SSPA Water Cooler - Heat Sink Arrived

12 in. x 12 1/4 in. x 3 5/8 in. Heat sink arrived today.  My two water cooler plates mount nicely on it.  Here is an idea of what I'm talking about.

Monday, October 17, 2016

SSPA Water Cooler - Most Parts Ordered

This past weekend I was busy sourcing the various parts of the Water Cooler for the SSPA I'm planning to build this winter.

I want to have a 5 gallon reservoir to start with, I may up that to 10 Gallon depending on how the initial tests go.  W9DR (Dave) did some work with water cooling his BLF188 (which is what I'm using in my amp as well).   In his video seen here he says that in the test he's running there's about a 4 foot 'head' on the water lines from the bucket to the cooler.  He goes on to say he's using 1 Gal in the bucket, and I believe he's pumping at 1 GPM (gal. per minute) through 3/8 inch tubing.  Dave goes on to say that his 1 Gallon bucket has about a 4 degree per hour rise time [with a single pallet].

My amp will have 4 pallets however will still only be running 1.5kW max.  I suspect that this will generate just slightly more heat for the water cooler maybe as much 25-35% more. (the difference between 800-1000 watts and 1.5kW).  I'm just guessing off the top of my head tho.

Assuming Dave's stats on his rise time and gpm are correct, a 5 gallon reservoir PLUS the addition of 2 large radiators with fans should be more than enough to handle the heat.  This is the barrel I've ordered.  (it's similar to the one I used for my DC dummy Load which was 10 Gallons - the price for them both was about the same, so if in doubt and you have the space I'd opt for the 10 Gal. going forward.  But I wanted to keep the foot-print down for this so opted on the 5 Gal. 

The Radiators I ordered are these.

The water pump is this.

The vinyl tubing for the plumping is this.  This stuff 3/8" ID but when heated in boiling water will stretch over the 1/2" barb fittings.  I'll also use hose clamps on the them.

The heat sink is this.  The cooler plates will mount on the flat surface (the bottom in this picture) which when used will be turned upside-down from it's orientation in this photo.
I will likely also add fans to push air through the fins at some point as well.

And these are my cooler plates (I already have these)

These are the valves I'll use (not ordered yet). These will mount flush on the sides of the barrel.  I didn't have to use valves, but it sure makes moving things around much easier if/when that's required.

I'll also want to order a pressure relief valve or a vent that'll mount on the top cover of the barrel.  I haven't looked for that yet, but that should be easy enough to fine.

This stuff all totaled minus a few misc. bits will cost about $500.00.  Not exactly as cheap and simple as just slapping the pallet amp heat spreaders on a large aluminium heat sink and tossing some huge fans on it.   But definitely quieter, and probably more efficient for heat dissipation.  DEFINITELY at lot more fun and interesting to build. :-)

I may swap out the tubing connector with some of these quick disconnect fittings also.

Wednesday, October 12, 2016

SSPA Water Cooler - Concept

I am planning to use water cooling (as well as some lower cfm fans which run quiet) for my 4x BLF188XR amp.  I don't know much about water cooling to be honest, so these are just some ideas I have.  I tend to use this blog as my online notebook.  So that I can refer back to it where ever I am.  So this may or may not be what I end up doing, but I suspect it will be close to this 'concept' at least.

OK so the pallet cooling plate is this bit of hardware.  I got these on eBay (2 of them).  I suspect I'll only use one, but I may end up using 2 instead.  I'm starting off with ONE for now.  But I have another in-reserve if needed.  These cost about $212 each new, I got them for $100 ea. on Ebay.  They're heavy, and very nicely made.  There's enough room to mount all four of the BLF188XR (w6pql) Pallets with heat spreader's if I go the route of using just one of these coolers.

On the back side of this (opposite the pallets that'll mount on the top) I will have a large heat sink with fins and 36 cfm fans blowing across them. (there would also be space for adding "62mm TEC" devices (like maybe 3 of them) between the cooler plate and the heat sink.  If I really need a boost.

The radiators noted above in the diagram are water cooling type rad's used for PC's.  These are 240mm long and 120mm wide and only cost $25 ea. on Ebay.

The reservoir will be 2 or 4 gallons I suspect.  I haven't decided on what to use here yet.  But it will probably be a metal barrel.  

lastly the pump is a Swiftech MCP655 which cost between $76 and $110 depending on where you buy from.  This particular one I'll use will cost $76 from Amazon Prime and it has a 5 speed adjustment on it.  

These pumps are SUPER QUIET and they tend to last forever!  They have 1/2" ID ports.  It's important to NOT restrict in the inlet port so I'll be using 1/2" ID tubing for the INPUT and probably 3/8" ID tubing on the OUTLET (bound for the cooler plate).

I suspect this setup will be EXTREMELY QUIET!  And that's the point of it.  I can't stand loud fans whining while I'm trying to listen to a speaker or while I'm talking on a mike in the background.

The power supply I've built for this amp is fairly quiet, and this area will be even quieter.  So all in all this should be a very quiet setup. 

Saturday, October 8, 2016

SSPA Power Supply - Mounted in it's Home

This is the first time I've mounted the power supply up in the 19-inch rack that will house both the power supply and the four-pallet BLF188xr *water-cooled* amp.  That's right, water cooled...oh, I didn't mention that to you before?  :-)  Yeah...I bought some very nice water-cooling plates for the next phase in this project.

Anyway...I digress.

So here's a few pictures of the control panel with the power supply mounted just below it in it's permanent 19" rack home.

(yeah, excuse the mess on the floor :-)  
When you do this much work 
in a short period of time things get a little messy :-)  

The next thing I need to do is clean up this wiring and get the Ammeter wires re-connected also.  

I really wanted to get all of this mounted in a box where it wouldn't extend out the back like that.  But this was the least expensive option I had at this point.  Most likely I'll build a box in the next revision of the power supply.  Because I really would like to have it all fit in the rack front to back. 

But for now this is all working great.  And I can live with the way it looks.

The next phase is to order the RF amp parts, and start building that.  I don't think it take nearly as long as this power supply did.  I'm glad I started this 'winter project' when I did.  

SSPA Power Supply - RFI/EMI resolved

A few weeks back (maybe a month ago - not sure) a friend of mine asked me how the RFI/EMI was with these Switch Mode power supplies I'm using.  At the time based on my tests at that time I hadn't noticed any RFI on my EME radio.

About a week or so ago I was finishing up after a load test I was doing and I happened to notice when I turned the power supply on, that my EME radio had been on, with the volume turned up and when I turned the sspa power supply off I suddenly heard the noise floor drop quite a bit.

After a LOT of research and poking around (literally) inside and outside the SSPA Power supply I've been building I finally decide to test for RFI using one of my spare power supplies that go inside the SSPA supply.  I had already prepped it to go in the SSPA supply in case I ever needed to replace a failed one, so it was just like the others in the project.

I decided to do some tests (this is pretty much all I could do to try to track this down at this point without an oscilloscope handy). 

  1. use my ears with the EME radio set to 6khz wide USB with AGC OFF and noise reduction and DSP turned OFF.
  2. visually watch the S-meter (when I turned the SSPA supply on/off.
  3. use WSJT 10's "measure" function to measure any changes to the noise floor.
  4. use my HackRF One and SDR# (software) with an RF Probe I made from a piece of coax.

This supply I would test had one of the protection diodes across the positive and negative terminals that I've previous written about.  One of the first things I did was test this spare supply with and without that diode attached.  It turned out that the major source of RFI I was noticing was directly related to this diode.  With it on, the band was full of noise, and off it would almost disappear.

So my next step was to remove all of those diodes.  Once that was done I went back to tracking down the RFI that was remaining.  At this point I set the spare supply aside and went back to working on the completed SSPA Supply with 8 of them inside it.

I installed 21 material 43 Fair Rite snap on ferrite beads on all the DC wires, as well as the AC wires inside the case.  This made a significant difference.  It got my noticable noise on the EME radio down to being only about +1dB when I turned the power supply on. 

(WSJT - measure function shows RFI at this point)

(note also the copper wire I'm using to ground the cases to Earth Ground on the large case)

The 12vdc source I use for control of various circuits inside the SSPA supply was running on 120vac on one side of the 240vac AFTER the EMI inlet filter.  I changed this over to run on 240v so that it would draw evenly on both sides of the 240vac.  I read that you shouldn't run something on one side of the 240vac if you are using an EMI filter because it sets it off-balance for lack of a seriously in-depth description.  I also replaced a 12 inch long Earth ground strap to this supply with about a 2 inch strap that runs to the SSPA supply case (which is Earth Grounded).  I added some capacitors across the terminals of the 200 amp 60vdc Final output 'contactor', because I was seeing a spike in noise when this was energized.

(also note the ferrite [left] added on the on/off control line for the 12vdc supply [right])

These changes got my RFI down to <= 0.5dB (measurable, and repeatable) on the EME radio.

The final step was to add capacitors on the 13.5 vdc supplies inside the SSPA supply.  On all 8 of the supplies.  I used 3.3uF and 4.7uF caps from the floating supplies Negative terminals to Earth Ground.  And I used 2200uF Low ESR electrolytic caps across the Positive and Negative terminals of each of the supplies.

After this I no longer can detect any RFI on the EME radio when the SSPA Supply is turned ON.

There IS however, RFI *INSIDE* the SSPA Supply case.  

(this was using my HackRF One and an RF Probe I built with the Probe INSIDE the SSPA case)

But it's no longer radiating out of the case.  So there may be more work to do, but at this point I'm calling it resolved.

(OUTSIDE the SSPA case - no sign of the RFI just some other local/internal birdies)

So I *WAS* seeing S5-6 noise when this all started.  Now there's NOTHING on the S-meter when I turn on the SSPA Supply.  And WSJT 10 'measure' function can't detect any changes in the noise floor when I power it on/off.  The HackRF can still spot RFI inside the case, but just outside the case it no longer does.  And my ears don't detect it at all.

PS I would like to re-install the protection diodes again at some point and I may attempt that.  I've since discovered that these diodes are probably ringing and I probably require some Fast "SOFT" recovery diodes instead.  I've also discovered that some folks add caps around the diodes on the same terminals.  It might be that the caps I have on mine noise could handle the noise from the diodes.  But for now I'm gonna leave it all alone until I can do another big load test.  (which may happen this weekend).

Wednesday, September 28, 2016

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).