Re: Placing Two Identical Regulated DC supplies in Parallel
John,
In retrospect, .1 ohm may be too high of a value.?? You might would rather have a .02 Ohm, that way 30A only drops .6V
Thanks
Andy
Thanks for the 0.1 ohm with 30 A fuse suggestion Andy, as regulation is not critical.
?
I was thinking about using the SS-30s for a repeater power amp. One could be a Micor 75W amp that could be set back, if needed, to draw? 25A at 13.8V. The other could be a 270W 6M Henry amp that draws 33A at 13.8V.?
?
I had tried an Astron SS-50 on the Henry amp, but it went into overtemp shutdown on somewhat? long repeater use time. I replaced it with a MeanWell HRP-600-12 with no overtemp problems, however the MeanWell required over 5 ferrites on the A+ A- leads with the A- grounded for RF emissions to the case. The AC input was? already RF suppressed at the factory, apparently allowing MeanWell to say the supply meets FCC Class B emissions. The MeanWell switcher with the small fan running at at high RPM when full speed during transmitting, very? slow speed with no current draw, is apparently the reliability weak spot with that supply if the fan is forced to run long times at high speed. That is why I was favoring the idea of using the large, slower, quieter intermittent running fan on Astron SS-30.
?
Years ago the Astron SS-12 and the Astron SS-18 were tried to power radios on the bench about 75 ft away from our 6M repeater antenna. Both caused 6M repeater receiver intermod desense when the 6M TX came on, but a replacement SS-30 did not. Also recent spectrum analyzer sweeps showed the Astron SS-30 to be clean, the HRP600-12 without ferrites, spikes actually worse around 130 MHz than 6M with the pick up antenna about 4 ft away from the supplies and exposed power leads. The HRP-600 with ferrites and especially when enclosed in a repeater cabinet was then also clean when transmitting.
?
Another switcher that in the past that appeared clean without much filtering for repeater use was the Diamond GZV4000, RATED 40A continuous, so that might
be a possibility, but I forget if it has overvoltage, overtemp, and overcurrent protection.
?
So I am extra cautious about switchers, especially outside a shielded enclosure, particularly on a commercial site, as don't want to degrade the site and lose the privilege!?
?
John
?
?
?
?
John,
?
I think to give an intelligent answer, we also need to know the application.?? If this were a repeater, I would recommend that you just have one on the PA and one on everything else.
?
Marlo gave you a lot of good information.
?
I have paralleled supplies before.?? The issue with the ASTRON SS-30 is that it is not temperature stable.?? I have had most of mine drop voltage slightly when they warm up.?? But they drop at different rates.? Some would drop by as little as .1V with no load after becoming warm.?? If you were to parallel, I would recommend using some .1 ohm resistors in series with each (high wattage), and also a fuse 30A on each leg. ? This would help balance them better (it wouldn't be perfect, but much better).?? This is similar to what linear supplies do when they parallel series pass transistors.?? They each have emitter resistors to help balance the shared load.?? But then you will lose a little of your regulation (if that matters).
?
I still wouldn't recommend doing it, as there are much better options and even cheaper.? Like a modified Astec DS-550 which can deliver 50A.
?
Andy
WJ9J
On Sat, Apr 19, 2025 at 8:13?AM Marlo Montanaro - KA2IRQ via <ka2irq= [email protected]> wrote:
I work for an industrial power supply manufacturer, in the engineering dept.? This is not a recommended configuration unless the power supplies are both designed for it.
?
You risk uneven load sharing which can overload one supply while the other does almost nothing.? The more heavily loaded supply could overheat or go into current limit.? This can happen with even very small voltage differences.... i.e., 12.00 vs. 12.05 volts.??
Despite the seemingly identical nature on paper, you can have large circulating currents between the supplies since there is almost no chance they will be perfectly voltage matched.? This wastes power and can damage internal components, especially if one supply is not designed to sink current.
?
If they are switching supplies, you can create feedback loops where the supplies may interact in strange ways, potentially causing oscillations or unstable behavior... there is nothing syncing the switching frequencies.
?
The supplies may have slightly different protection thresholds for overcurrent or overvoltage.? If one supply trips in a fault condition, that leaves the other supply to suddenly take the full load.? If you design things so one supply can take the full load to avoid this, then you really don't need two supplies.
?
Supplies may power up at slightly different rates which can cause temporary overcurrent conditions.
?
The supplies we manufacture are designed for parallel operation but to do this they have several sophisticated control boards, data communication between them, and very heavy duty buss bars connected between them to handle high current conditions and provide a very low resistance path between the outputs.
?
--
73,
Marlo
KA2IRQ
?
?
?
?
?
|
Re: Difficulty Programming a Maxtrac 300, 32 Channel
I think it¡¯s com 1 or com 2. ?Don¡¯t believe there are any other options.?
This is from the days long before USB.?
|
Difficulty Programming a Maxtrac 300, 32 Channel
New to the group and hope you guys can help out in this.
?
I had a real old laptop an Inpiron 3200 that took a crap and it had the RSS software on it.
?
Fortunately, I had made a copy of the RSS on my other computer and I am able to run it in DOSBox but cannot communicate with the rig.
?
The computer I am using only has a USB connector to which I plugged in a USB to serial cable, this went to my RIB box and from there onto the rig.
?
However, communicating with the rig fails.
?
I was wondering if the 300 has a specific Com port and baud rate settings that I could change on this computer to get communication moving along.
?
Thanks,
?Bill
K2WH
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Re: DB4060 Series Dfor a 4-cuplexer Cans
Tim,
From the information here on the group and referencing , a factory B range 4060 or 4062 requires
"004" in the Low Pass and "005" in the High Pass.? So - you should
be good to go...
The screws are SAE - but I don't remember the size.
Kevin
On 4/19/2025 12:46 PM, TIM HARDY via groups.io wrote:
toggle quoted message
Show quoted text
Hello,
I checked the loops on my 4062 cavities to verify the range of the duplexer.
The HIGH pass cavities used loop "005", LOW pass used loop "004"
Am I correct to assume this duplexer is a "B" range? (Factory set to 149.825) Sure hope the duplexer will be usable at 146.xxxx mHz!
One more question. I lost one of the Phillip's head stainless screws that hold the loop box to the can. What size are they? Are they metric?
Thank you,
Tim
AE7TH
On 04/18/2025 11:19 AM PDT Jeff DePolo WN3A via groups.io <jd0@...> wrote:
It's just a matter of retuning.
There is no difference between the 2 sides except how you have it tuned.
Wrong. The loops are different between high-pass and low-pass. And, the loops are different depending on bandsplit.
If you don't have the right loops, or are using the loops for the wrong response (high-pass versus low-pass) you probably won't even make rated space for notch depth. If they are correct for the bandsplit and pass response you'll get 85 dB for a 4-cavity DB4060.
--- Jeff WN3A
|
Re: In search of dB4060 -005 coupling loops or assemblies
On 4/19/2025 12:12 PM, Keith via groups.io wrote: I have a set of those too.? Same issue.? I was able to procure the engineering drawings for the loops and I am looking at making a set for myself. And possibly building a die set to make multiple sets.? The copper is standard grounding strap which I have a supply of.? Needing to figure out shearing the strips to the correct width.? If I can figure that out I may move forward with making a couple dozen sets up.? More to follow Keith, Are you willing to share the engineering drawings? Kevin
|
Re: DB4060 Series Dfor a 4-cuplexer Cans
The cavity will not go into the milli Hertz range.
If you meant mega Hertz, please use the correct designation.
As far as the screw size goes, take another one out and take it to your hardware store.
They can help you.
You should start a junk box of assorted hardware from disassembled equipment so you will have hardware on hand.
Glenn
Wb4UIV
toggle quoted message
Show quoted text
On 4/19/2025 12:46 PM, TIM HARDY via groups.io wrote: Hello,
I checked the loops on my 4062 cavities to verify the range of the duplexer.
The HIGH pass cavities used loop "005", LOW pass used loop "004"
Am I correct to assume this duplexer is a "B" range? (Factory set to 149.825) Sure hope the duplexer will be usable at 146.xxxx mHz!
One more question. I lost one of the Phillip's head stainless screws that hold the loop box to the can. What size are they? Are they metric?
Thank you,
Tim
AE7TH
On 04/18/2025 11:19 AM PDT Jeff DePolo WN3A via groups.io <jd0@...> wrote:
It's just a matter of retuning.
There is no difference between the 2 sides except how you have it tuned. Wrong. The loops are different between high-pass and low-pass. And, the loops are different depending on bandsplit.
If you don't have the right loops, or are using the loops for the wrong response (high-pass versus low-pass) you probably won't even make rated space for notch depth. If they are correct for the bandsplit and pass response you'll get 85 dB for a 4-cavity DB4060.
--- Jeff WN3A
--
-----------------------------------------------------------------------
Glenn Little ARRL Technical Specialist QCWA LM 28417
Amateur Callsign: WB4UIV wb4uiv@... AMSAT LM 2178
QTH: Goose Creek, SC USA (EM92xx) USSVI, FRA, NRA-LM ARRL TAPR
"It is not the class of license that the Amateur holds but the class
of the Amateur that holds the license"
|
Re: Placing Two Identical Regulated DC supplies in Parallel
Thanks for the 0.1 ohm with 30 A fuse suggestion Andy, as regulation is not critical.
?
I was thinking about using the SS-30s for a repeater power amp. One could be a Micor 75W amp that could be set back, if needed, to draw? 25A at 13.8V. The other could be a 270W 6M Henry amp that draws 33A at 13.8V.?
?
I had tried an Astron SS-50 on the Henry amp, but it went into overtemp shutdown on somewhat? long repeater use time. I replaced it with a MeanWell HRP-600-12 with no overtemp problems, however the MeanWell required over 5 ferrites on the A+ A- leads with the A- grounded for RF emissions to the case. The AC input was? already RF suppressed at the factory, apparently allowing MeanWell to say the supply meets FCC Class B emissions. The MeanWell switcher with the small fan running at at high RPM when full speed during transmitting, very? slow speed with no current draw, is apparently the reliability weak spot with that supply if the fan is forced to run long times at high speed. That is why I was favoring the idea of using the large, slower, quieter intermittent running fan on Astron SS-30.
?
Years ago the Astron SS-12 and the Astron SS-18 were tried to power radios on the bench about 75 ft away from our 6M repeater antenna. Both caused 6M repeater receiver intermod desense when the 6M TX came on, but a replacement SS-30 did not. Also recent spectrum analyzer sweeps showed the Astron SS-30 to be clean, the HRP600-12 without ferrites, spikes actually worse around 130 MHz than 6M with the pick up antenna about 4 ft away from the supplies and exposed power leads. The HRP-600 with ferrites and especially when enclosed in a repeater cabinet was then also clean when transmitting.
?
Another switcher that in the past that appeared clean without much filtering for repeater use was the Diamond GZV4000, RATED 40A continuous, so that might
be a possibility, but I forget if it has overvoltage, overtemp, and overcurrent protection.
?
So I am extra cautious about switchers, especially outside a shielded enclosure, particularly on a commercial site, as don't want to degrade the site and lose the privilege!?
?
John
?
?
On 04/19/2025 11:19 AM EDT wj9jrg via groups.io <wj9jrg@...> wrote:
?
?
John,
?
I think to give an intelligent answer, we also need to know the application.?? If this were a repeater, I would recommend that you just have one on the PA and one on everything else.
?
Marlo gave you a lot of good information.
?
I have paralleled supplies before.?? The issue with the ASTRON SS-30 is that it is not temperature stable.?? I have had most of mine drop voltage slightly when they warm up.?? But they drop at different rates.? Some would drop by as little as .1V with no load after becoming warm.?? If you were to parallel, I would recommend using some .1 ohm resistors in series with each (high wattage), and also a fuse 30A on each leg. ? This would help balance them better (it wouldn't be perfect, but much better).?? This is similar to what linear supplies do when they parallel series pass transistors.?? They each have emitter resistors to help balance the shared load.?? But then you will lose a little of your regulation (if that matters).
?
I still wouldn't recommend doing it, as there are much better options and even cheaper.? Like a modified Astec DS-550 which can deliver 50A.
?
Andy
WJ9J
On Sat, Apr 19, 2025 at 8:13?AM Marlo Montanaro - KA2IRQ via <ka2irq= [email protected]> wrote:
I work for an industrial power supply manufacturer, in the engineering dept.? This is not a recommended configuration unless the power supplies are both designed for it.
?
You risk uneven load sharing which can overload one supply while the other does almost nothing.? The more heavily loaded supply could overheat or go into current limit.? This can happen with even very small voltage differences.... i.e., 12.00 vs. 12.05 volts.??
Despite the seemingly identical nature on paper, you can have large circulating currents between the supplies since there is almost no chance they will be perfectly voltage matched.? This wastes power and can damage internal components, especially if one supply is not designed to sink current.
?
If they are switching supplies, you can create feedback loops where the supplies may interact in strange ways, potentially causing oscillations or unstable behavior... there is nothing syncing the switching frequencies.
?
The supplies may have slightly different protection thresholds for overcurrent or overvoltage.? If one supply trips in a fault condition, that leaves the other supply to suddenly take the full load.? If you design things so one supply can take the full load to avoid this, then you really don't need two supplies.
?
Supplies may power up at slightly different rates which can cause temporary overcurrent conditions.
?
The supplies we manufacture are designed for parallel operation but to do this they have several sophisticated control boards, data communication between them, and very heavy duty buss bars connected between them to handle high current conditions and provide a very low resistance path between the outputs.
?
--
73,
Marlo
KA2IRQ
?
?
?
?
?
|
On Sat, Apr 12, 2025 at 07:06 PM, Chad Nelson wrote:
. Should maybe find tiny surveillance camera and connect it up so I have monitoring capability visually. Just need to figure out how to get it to transmit over the Internet to my location 60 miles away.
Chad,
Some of those under $20 miniature surveillance cameras have SD card slots and will capture 2 weeks of video. There is no reason to stream live video to see if the paint is drying. You can also set it only to capture video upon motion detection. I have installed them for a coupl eof grandma's who have no internet or computers. If they get broken into we've got video on the SD card I can pull for the police.?
?
Now- regarding if you need to actually get video 60 miles.. if you have internet at the site, My camera "called" my smart phone. and posted on the phone, it had detected motion and I watched someone turn around in my driveway from 1000 miles away..
?I surmise? the video clip was only streamed when upon demand I viewed it on my phone. I viewed the video that following day as the video was under night vision- black and white only. Daytime is full color.? That video came from my house internet connection. But no internet at the site?
?
Now I have a 4G wifi hot spot.
I have not set it up, for video.. But I use it for ALLSTAR audio. a Video movie (90 minutes approximate) at 1080i is about 2.5 to 3 gigs.. and about 5Mbps speed...
4G speeds I get 25-34 Mbps speed all the time I test for speed. So I could watch 1 HD movie on 4G.. maybe stream 2 at the same time.
?
On Ebay, I bought a T-mobile, new in the box 4G hot spot..surplus Here's one for an example:
$13.99 free shipping.... unlocked!
When I ordered it I ordered a SIM card from Tello.com They have a? 1Gb ($5/mo) 2Gb plan for $6 a month
Tello.com has a "bring your own phone" plan "DATA ONLY" 5Gb per month for $10 a month- Select 1-2-5-10 GB data- NO Minutes (no phone calls)
Tello uses AT&T and T-mobile towers..
?
You plug in the SIM card and activate per the instruction on the Tello.com website. If you go over data, you can add or just get throttled at peak times till your month renews.
?
I have the hotspot in my car... I have a RF shark openspot 2 for digital Fusion and DMR as well as a SHARI for Allstar VOIP. My ford radio I can connect to I heart Radio and Amazon Music. So I can listen to WOR NYC in Kansas..
3 months ago I checked my usage and had 3 days left and only used 3 Gb data.. That month I drove Wichita KS to Washington DC for the inauguration. Had wifi all the way....
That T-mobile will allow you to connect up to 10 devices and you can select 2.4 and5Ghz wifi..? Well worth the $14 cash layout..
It you want the hotspot on all the time, you connect it to USB power ( 5V DC) and pull the battery..?
?
I only have 21 miles to my repeater site.. Not 60, but this is very viable as you could throw up a Raspberry PI there and control all kinds of things..
?
Perhaps this is the solution for plenty of us. I like having my HT and connection to the car, then world wide. Finally, i have not played with it, but the T-mo hot spot does have port UDP & TCP forwarding.? i don't know if they are implemented but that surprised me as a AT&T hotspot does not.
?
Larry W8LM
Old Goat Ranch
Mulvane, KANSAS
?
?
?
|
Re: DB4060 Series Dfor a 4-cuplexer Cans
Hello,
I checked the loops on my 4062 cavities to verify the range of the duplexer.
The HIGH pass cavities used loop "005", LOW pass used loop "004"
Am I correct to assume this duplexer is a "B" range? (Factory set to 149.825) Sure hope the duplexer will be usable at 146.xxxx mHz!
One more question. I lost one of the Phillip's head stainless screws that hold the loop box to the can. What size are they? Are they metric?
Thank you,
Tim
AE7TH
toggle quoted message
Show quoted text
On 04/18/2025 11:19 AM PDT Jeff DePolo WN3A via groups.io <jd0@...> wrote:
It's just a matter of retuning.
There is no difference between the 2 sides except how you have it tuned. Wrong. The loops are different between high-pass and low-pass. And, the loops are different depending on bandsplit.
If you don't have the right loops, or are using the loops for the wrong response (high-pass versus low-pass) you probably won't even make rated space for notch depth. If they are correct for the bandsplit and pass response you'll get 85 dB for a 4-cavity DB4060.
--- Jeff WN3A
|
Re: In search of dB4060 -005 coupling loops or assemblies
I have a set of those too.? Same issue.? I was able to procure the engineering drawings for the loops and I am looking at making a set for myself. And possibly building a die set to make multiple sets.? The copper is standard grounding strap which I have a supply of.? Needing to figure out shearing the strips to the correct width.? If I can figure that out I may move forward with making a couple dozen sets up.? More to follow?
|
Re: Swap: Ics controllers quantar 1x for a northcomm quantar ecm.
Hi,
were we going to swap controllers? Or was I going to buy the northcomm from you?
I would just buy a new northcomm but the northcomm site doesn't accept PayPal so I can't use my PP Credit there.
I can go either way. Swap or purchase.
Thanks.
Robert
I also have some accessories for the ics either here or the way. I have adapter cables already and have a mini USB to ethernet port on the way.
Did you make it back home?
I do. I will back home Friday and I can give many more details.?
|
Zetron 48-JR Shematic and RX Audio
Hi to All,
I have a Zetron 48-JR with a receive audio problem and was wondering if a members has the schematic of this contr?ler?
On the R-B web site I could only find the brochure and installation manual.
The parts list is there but no schematic or board d¨¦tail like other Zetron manual?
My problem is when your turn On the contr?ler it work's but the audio is a bit degraded.
With the time passing the audio get more and more degraded to a point that the contr?ler do not decode CTCSS and DCS no more.
This time is very short, a few minutes at the most from the trurn On and the time it does not work any more.
Has anybody sean this problem before?
Nice Easter Holiday to All.
Best 73
Carl
VA2CMB
|
Re: Placing Two Identical Regulated DC supplies in Parallel
John,
I think to give an intelligent answer, we also need to know the application.?? If this were a repeater, I would recommend that you just have one on the PA and one on everything else.
Marlo gave you a lot of good information.
I have paralleled supplies before.?? The issue with the ASTRON SS-30 is that it is not temperature stable.?? I have had most of mine drop voltage slightly when they warm up.?? But they drop at different rates.? Some would drop by as little as .1V with no load after becoming warm.?? If you were to parallel, I would recommend using some .1 ohm resistors in series with each (high wattage), and also a fuse 30A on each leg. ? This would help balance them better (it wouldn't be perfect, but much better).?? This is similar to what linear supplies do when they parallel series pass transistors.?? They each have emitter resistors to help balance the shared load.?? But then you will lose a little of your regulation (if that matters).
I still wouldn't recommend doing it, as there are much better options and even cheaper.? Like a modified Astec DS-550 which can deliver 50A.
Andy WJ9J On Sat, Apr 19, 2025 at 8:13?AM Marlo Montanaro - KA2IRQ via <ka2irq= [email protected]> wrote:
I work for an industrial power supply manufacturer, in the engineering dept.? This is not a recommended configuration unless the power supplies are both designed for it.
?
You risk uneven load sharing which can overload one supply while the other does almost nothing.? The more heavily loaded supply could overheat or go into current limit.? This can happen with even very small voltage differences.... i.e., 12.00 vs. 12.05 volts.??
Despite the seemingly identical nature on paper, you can have large circulating currents between the supplies since there is almost no chance they will be perfectly voltage matched.? This wastes power and can damage internal components, especially if one supply is not designed to sink current.
?
If they are switching supplies, you can create feedback loops where the supplies may interact in strange ways, potentially causing oscillations or unstable behavior... there is nothing syncing the switching frequencies.
?
The supplies may have slightly different protection thresholds for overcurrent or overvoltage.? If one supply trips in a fault condition, that leaves the other supply to suddenly take the full load.? If you design things so one supply can take the full load to avoid this, then you really don't need two supplies.
?
Supplies may power up at slightly different rates which can cause temporary overcurrent conditions.
?
The supplies we manufacture are designed for parallel operation but to do this they have several sophisticated control boards, data communication between them, and very heavy duty buss bars connected between them to handle high current conditions and provide a very low resistance path between the outputs.
?
--
73,
Marlo
KA2IRQ
?
?
?
|
Re: Running echo link on a repeater
If you run AllstarLink with the repeater, there is a module for Echolink that has setup parameters for incorporating it in AllstatLink.? AllstarLink also makes repeater linking in the future a bit easier.
Michael L Robinson, KC0TA
¡°In the beginning of a change the Patriot is a scarce man, and brave, and hated and scorned. When his cause succeeds, the timid join him, for then it costs nothing to be a Patriot.¡±
¨D Mark Twain
When Tyranny becomes Law, Revolution becomes Duty!
There used to be a program called Echo Producer that had some very useful features on it.
Hi, does anyone have any good resources? Other than echo Link to help me set levels for box on a repeat running echo Link? I do it by trial and error because I've never found a good resource to help me set that correctly, people say I'm cutting out all the time and people coming through my link for Peter seem to cut out a lot. I am going to get a West mountain radio rig blaster plug-in play next week which will maybe help that problem. But in the meantime, does anyone have any settings? Suggestions for my echo link note?
Chad Nelson WI9HF/WRPL979
Janesville Wisconsin
608-754-8671
Send from my spectrum iPhone 16.
|
Re: Placing Two Identical Regulated DC supplies in Parallel
I¡¯m glad it was helpful John. ? I know there is some info out there on how to do it, and I¡¯m not saying it can¡¯t be done¡ just really not a recommended configuration. ? I work for TDK-Lamba in NJ, where we design and manufacture our Genesys and Genesys+ supplies.? I¡¯m actually working on a new line of equipment for a customer and I literally pulled parallel kits from our assembly line yesterday to begin testing this exact configuration with both two and four parallel supplies. ? Granted, things are much smaller with fixed 12V supplies, but the principle is the same.? And even with remote sense hooked up, you risk a mis-match causing oscillation and noise as the supplies try to figure it out.? That¡¯s not what you need in a radio/repeater scenario, especially with the load constantly changing as the transmitter goes on and off during a QSO.? We have oscilloscope pictures during dynamic load testing and the voltage spikes are crazy- all that needs to be suppressed, or at least accounted for.? Switching several amps as the load changes can easily cause voltage spikes over 100V for several micro-seconds on the supply output, and if the filter caps aren¡¯t rated for that, you¡¯ll only know it happened because of the smoke and the loud bang.? (Trust me, the caps will blow to protect any fuses in the circuit.)
If you have two supplies you were planning on using, I would honestly sell them and put the money towards one supply that can handle the load plus 25-50%.? Just my 2-cents. ? Good luck!! ? ?
toggle quoted message
Show quoted text
From: JOHN HASERICK <jhaserick84@...>
Sent: Saturday, April 19, 2025 8:29 AM
To: [email protected]; Marlo Montanaro - KA2IRQ <ka2irq@...>
Subject: Re: [repeater-builder] Placing Two Identical Regulated DC supplies in Parallel? Thank you for the extensive information Marlo, and the other great replies also. It sure was tempting to do, until your reply, as these Astron SS-30 supplies have overvoltage, overcurrent, and overtemp protection, and the internal voltage sensor wires are right next to? the output terminals, which could have short low voltage drop leads between supplies. On 04/19/2025 8:13 AM EDT Marlo Montanaro - KA2IRQ <ka2irq@...> wrote: I work for an industrial power supply manufacturer, in the engineering dept.? This is not a recommended configuration unless the power supplies are both designed for it. You risk uneven load sharing which can overload one supply while the other does almost nothing.? The more heavily loaded supply could overheat or go into current limit.? This can happen with even very small voltage differences.... i.e., 12.00 vs. 12.05 volts.??
Despite the seemingly identical nature on paper, you can have large circulating currents between the supplies since there is almost no chance they will be perfectly voltage matched.? This wastes power and can damage internal components, especially if one supply is not designed to sink current. If they are switching supplies, you can create feedback loops where the supplies may interact in strange ways, potentially causing oscillations or unstable behavior... there is nothing syncing the switching frequencies. The supplies may have slightly different protection thresholds for overcurrent or overvoltage.? If one supply trips in a fault condition, that leaves the other supply to suddenly take the full load.? If you design things so one supply can take the full load to avoid this, then you really don't need two supplies. Supplies may power up at slightly different rates which can cause temporary overcurrent conditions. The supplies we manufacture are designed for parallel operation but to do this they have several sophisticated control boards, data communication between them, and very heavy duty buss bars connected between them to handle high current conditions and provide a very low resistance path between the outputs.
|
Re: Placing Two Identical Regulated DC supplies in Parallel
Thank you for the extensive information Marlo, and the other great replies also. It sure was tempting to do, until your reply, as these Astron SS-30 supplies have overvoltage, overcurrent, and overtemp protection, and the internal voltage sensor wires are right next to? the output terminals, which could have short low voltage drop leads between supplies.
?
John
On 04/19/2025 8:13 AM EDT Marlo Montanaro - KA2IRQ <ka2irq@...> wrote:
?
?
I work for an industrial power supply manufacturer, in the engineering dept.? This is not a recommended configuration unless the power supplies are both designed for it.
?
You risk uneven load sharing which can overload one supply while the other does almost nothing.? The more heavily loaded supply could overheat or go into current limit.? This can happen with even very small voltage differences.... i.e., 12.00 vs. 12.05 volts.??
Despite the seemingly identical nature on paper, you can have large circulating currents between the supplies since there is almost no chance they will be perfectly voltage matched.? This wastes power and can damage internal components, especially if one supply is not designed to sink current.
?
If they are switching supplies, you can create feedback loops where the supplies may interact in strange ways, potentially causing oscillations or unstable behavior... there is nothing syncing the switching frequencies.
?
The supplies may have slightly different protection thresholds for overcurrent or overvoltage.? If one supply trips in a fault condition, that leaves the other supply to suddenly take the full load.? If you design things so one supply can take the full load to avoid this, then you really don't need two supplies.
?
Supplies may power up at slightly different rates which can cause temporary overcurrent conditions.
?
The supplies we manufacture are designed for parallel operation but to do this they have several sophisticated control boards, data communication between them, and very heavy duty buss bars connected between them to handle high current conditions and provide a very low resistance path between the outputs.
?
--
73,
Marlo
KA2IRQ
?
?
?
|
Re: Placing Two Identical Regulated DC supplies in Parallel
I work for an industrial power supply manufacturer, in the engineering dept.? This is not a recommended configuration unless the power supplies are both designed for it.
?
You risk uneven load sharing which can overload one supply while the other does almost nothing.? The more heavily loaded supply could overheat or go into current limit.? This can happen with even very small voltage differences.... i.e., 12.00 vs. 12.05 volts.??
Despite the seemingly identical nature on paper, you can have large circulating currents between the supplies since there is almost no chance they will be perfectly voltage matched.? This wastes power and can damage internal components, especially if one supply is not designed to sink current.
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If they are switching supplies, you can create feedback loops where the supplies may interact in strange ways, potentially causing oscillations or unstable behavior... there is nothing syncing the switching frequencies.
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The supplies may have slightly different protection thresholds for overcurrent or overvoltage.? If one supply trips in a fault condition, that leaves the other supply to suddenly take the full load.? If you design things so one supply can take the full load to avoid this, then you really don't need two supplies.
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Supplies may power up at slightly different rates which can cause temporary overcurrent conditions.
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The supplies we manufacture are designed for parallel operation but to do this they have several sophisticated control boards, data communication between them, and very heavy duty buss bars connected between them to handle high current conditions and provide a very low resistance path between the outputs.
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73,
Marlo
KA2IRQ
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Re: Placing Two Identical Regulated DC supplies in Parallel
There¡¯s an article on the Astron page at repeater-builder that walks you through it.?
On Fri, Apr 18, 2025 at 06:01 PM, Butch-tiny puppy wrote:
I've never done it, but I have a couple astron supplies that have a third connection that is supposed if hooked in parallel.? I don't know what it does.?
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Butch Bussen WA0VJR butchb@...irlp 7135 allstar 56023 echolink 790800
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Re: Wacom WP-678 Cable lengths
Sounds good. I will make up the ones for the cavities I have.?
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On Apr 18, 2025, at 6:00?PM, Don Clark via groups.io <kb5kwv@...> wrote:
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All of the cables both between
the cavity "T"'s and the antenna "T" is the same.
On 4/18/2025 12:41 PM, James Kossow via
groups.io wrote:
Sorry about
the name/person mix up! That is close enough for me!? What
about the cable lengths from the cavity to the Tee for the
antenna?? Are those the same too?
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TNX Jim
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Sent from
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This
is the wrong Don, but I just measured a couple of mine.
This is tip to tip of the male pin. Very close to the end of
connector also.? 3.74"
Or 3.737" to 3.745", and I doubt you can cut a coax that
close, along with my measuring errors.
Don
KB5KWV
On 4/17/2025 3:20 PM, James Kossow via
groups.io wrote:
Dan thank you for your reply, can you get me the exact measurements of the cavity-to-cavity cable length and the cavity to tee (antenna tee) length?
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Thank you,
?Jim?
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On Tuesday, April 15, 2025 at 08:43:21 AM PDT, James Kossow <jim.kossow@...> wrote:
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It is the one port version.?
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TNX jim.?
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On Apr 15, 2025, at 6:48?AM, Jeff DePolo WN3A via groups.io <jd0@...> wrote:
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????* I have a Wacom WP-678 that is missing the interconnect cables.?
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Is it a WP-678-R2 (two ports per cavity) or an original WP-678 (one port per cavity with a tee on top)?
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??????????????????????????????????????????????????????????????????????????????? --- Jeff WN3A
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Re: Placing Two Identical Regulated DC supplies in Parallel
Is the PS isn¡¯t built for it, there is always a challenge in balancing current. Even when using diode devices, one unit always supplies a greater portion of the current. ? There are a number of ¡°commercial¡± supplies in the market that support paralleling, from 2 units to several. Who wants to spend $650 on an RS70M that ¡°just¡± deliver 57A continuous? Especially if you can get 200A for less money? ? The key question, is are you looking for high availability, load sharing, or both? ? Lower cost units typically you droop current sharing. This type is frequently 1+1, though there are some (common) implementations that scale up to 4 units. ? Convection or forced air is often a consideration. Convection¡. 12v units of 30A each are available up to 4 in droop configs. One item that can get you in this implementation is that a minimum amount of current is required, usually at least 5%, thus if you had 4 30A units in parallel, you¡¯d need a continuous current draw of 6A (30A x 5% x 4). For uses such as 12V amps that key on and off, this doesn¡¯t work. ? Forced air options are more widely available, however, they are noisy. Common options deliver up to 200A @ 12V for under $500. ? Matt AL0R ? ?
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From: [email protected] < [email protected]> On Behalf Of John via groups.io Sent: Friday, April 18, 2025 19:49 To: [email protected]Subject: [repeater-builder] Placing Two Identical Regulated DC supplies in Parallel ? Any what to look out for situations for this, besides matching voltages? I took an Astron SS-30M that was not switched on and back fed 5-18VDC from a metered regulated bench supply to it. With initial switch on at 13.8V from the bench supply, the? "on" current was 200mA that soon dropped to 10mA. The volt meter on the SS-30M then read 13.8V. SS-30M analog amp meter still at zero to the eye. From that test , it appears that no isolating diodes from SS-30 power supplies to common output would be required, and as long as the output voltages are equal, both supplies should carry half of the required current. It seems it would be best would be to use SS-30M supplies so the equal current draws can be confirmed visually, but not really necessary if equal voltages stay equal.? If available, is it significantly important or just preferred to connect both? supplies voltage sensing leads?? The SS-30 supplies? do not have externally reachable sense wires, but if really needed, they could be brought outside the case.
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Bill
Kevin Custer
Larry Macionski
Keith
Carl Beaudry
Marlo Montanaro - KA2IRQ