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Power supply 0-30V, 0-8A again Electronic Lab

pier 6504 22
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  • Power supply 0-30V, 0-8A again Electronic Lab

    Hi.

    I made a power supply, nothing innovative because it is a good construction that has been going through the internet for over a dozen years.
    Power supply 0-30V, 0-8A again Electronic Lab
    With this construction, I put more emphasis on the design (at least I think so). Despite quite a long thought process, this power supply was not without mistakes. Fortunately, these errors do not force any major changes, such as cutting paths, etc.
    It started with the fact that I fell into my hands ups and in it quite a large transformer, 2x15V ~ with power I guess 650W. Additionally, it has a 22V ~ winding used for an auxiliary power supply. Designation of the transformer S 650/4 R11.
    As I had no idea where to use it, it fell on the power supply, there are never too many of these. I had no experience with other designs, so I focused on the Electronic Lab.
    I spent a lot of time on the power supply board. I have equipped the power supply with a transformer winding switching system and a 12 and 5V auxiliary power supply. The rest is unchanged, except for changing the transistor controlling the output stage and adding a second power transistor. Such modifications are also standard in this design.
    The mistakes I made on this board were the wrong footprint of the BD139 transistor, which meant that its legs had to be changed.
    Power supply 0-30V, 0-8A again Electronic Lab
    The rest are a few mislabeled resistors. Apparently nothing but I felt nervous when starting up.
    The meter is my design. It works, but it is still under development. So far, there is no option to calibrate indications or any configuration. The meter has the ability to control the fan, so far as you can see there is no fan, it only shows the temperature of the heat sink. On this PCB, I placed the connectors too close, so they do not fit next to each other and some wires had to be soldered directly into the PCB.
    The meter is built on a large 2x16 display.
    As you can see, the tiles are made in Asia, JLCPCB to be precise.
    Everything is packed in the housing marked E208B. Very nice box, stiff. I was able to buy a heat sink that fits the housing perfectly, I just had to cut off a piece for the power socket.
    The front panel, due to the dimensions of the housing and the display used, seems a bit non-functional, especially with the knobs, but I have no problem with operating them. Maybe the purple overlay on the LCD does not fit a bit, but it was just one that was available from the printer at the time. Yes, this plastic is specially designed and printed for this project. I was always attracted to the poor display in the housing. No descriptions on the panel because, first of all, I have no idea yet, and second, what should I describe here?



    Power supply 0-30V, 0-8A again Electronic Lab

    During the short tests, the power supply was fine. If I wanted to load it longer with maximum currents, I would have to think about another series resistor. The current 2x 0.47om 5W after three minutes with a current of 7A has a temperature close to 80 degrees. Bridge and heat sink transistors even do it. If it is something, I can add a fan.

    The op-amps used still need to be explained.
    In the design phase, I did not take into account the higher than acceptable voltage of the amplifiers from the second tap of the transformer. I thought, I advised on the forum how to figure it out. A quick solution would be to replace the amplifiers with those that can be powered with higher voltage, but the availability and prices of such cubes are not encouraging. The second option would be to add a stabilizer for op-amps, but this is an addition to the circuit and cutting paths.
    In the end, the usual UA741 were left, yes, I know they work with too high supply voltage, but during the tests nothing happened with them. They work steadily and I have not noticed excessive heating. But of course, I do not recommend imitating.
    Feel free to comment.
    Greetings Piotr.

    Power supply 0-30V, 0-8A again Electronic Lab Power supply 0-30V, 0-8A again Electronic Lab Power supply 0-30V, 0-8A again Electronic Lab
    Power supply 0-30V, 0-8A again Electronic Lab Power supply 0-30V, 0-8A again Electronic Lab Power supply 0-30V, 0-8A again Electronic Lab

    Cool? Ranking DIY
    Can you write similar article? Send message to me and you will get SD card 64GB.
    About Author
    pier
    Level 23  
    Offline 
    pier wrote 2131 posts with rating 1696, helped 34 times. Live in city Biłgoraj. Been with us since 2006 year.
  • #2
    padus
    Level 11  
    Plus for nice workmanship.

    Quote:
    In the end, the usual UA741 were left, so I know they work with too high supply voltage

    Well, you'll see how it goes on, I'm far from criticizing.

    I have already covered this topic. I currently have 4 ElLabs power supplies. They work pretty well.

    Recently, I designed a processor power supply according to my idea. At the moment, my monster is powered by two 400W transformers, and I get a load of 1 Ohm 27V 27A, which gives over 720W of power at the output. At 2 ohms, I have 37V (18A) and over 680W. Control prepared for the STM32 processor.
  • #3
    krakarak
    Level 41  
    You write that the tiles are made in Asia, which is what? Did you receive etched, drilled plates with solder mask and soldered everything yourself or did you receive plates with soldered elements? ...
  • #4
    madamsz1
    Level 38  
    pier wrote:
    No descriptions on the panel because, first of all, I have no idea yet, and secondly, what can I describe here?

    Absolutely, especially since you probably have the "+" and "-" sockets in the same color, so it's easy to make a mistake.

    You write about the ale amplifiers :) , you haven't added a diagram where to attach to it :)
    The construction is nicely made, at the maximum load these cables to the sockets do not heat up? (they seem a bit thin to me, but ... compared to those from the trafa they are probably identical)
  • #5
    szeryf3
    Level 25  
    As for me, the center is very well made.
    The box is small and handy.
  • #6
    zgierzman
    Level 30  
    madamsz1 wrote:
    Absolutely, especially since you probably have the "+" and "-" sockets in the same color, so it's easy to make a mistake.


    Perhaps it looks like this on an amber CGA monitor, but for me the colors are obvious ...

    Power supply 0-30V, 0-8A again Electronic Lab
  • #8
    allanrid
    Level 11  
    Nice idea with a display built-in. Only the effect is spoiled by this glue of glue :-) .
  • #9
    gorki73
    Level 36  
    I really like it, the aesthetically made work, I don't know how much the power supply weighs, and I don't know about you, but I would have a carrying handle like this:
    Power supply 0-30V, 0-8A again Electronic Lab
  • #10
    aka63
    Level 12  
    allanrid wrote:
    Nice idea with a display built-in. Only the effect is spoiled by this glue of glue :-) .
    It's probably not a glue blot, but a non-peeled foil protecting the display.
  • #11
    eurotips
    Level 38  
    Professional, tailor-made housing.
    Trafo solid, but the lack of detachments can quickly take its toll.
    Temperature measurement is a big plus, as is the fan.
    Take care of the current limitation while turning on the toroid.
  • #12
    pier
    Level 23  
    krakarak wrote:
    You write that the tiles are made in Asia, which is what? Did you receive etched, drilled plates with solder mask and soldered everything yourself or did you receive plates with soldered elements? ...


    I designed the tiles and the Chinese made them, that's how it works. I soldered myself.

    eurotips wrote:
    Professional, tailor-made housing.
    Trafo is solid, but the lack of detachments can quickly take its toll.
    Temperature measurement is a big plus, as is the fan.
    Take care of the current limitation when turning on the toroid.


    Pier wrote:

    I have equipped the power supply with a winding switching system ...
  • #13
    sq3evp
    Level 29  
    Nice workmanship - your own design as a whole? What is displayed on the LCD?
  • #14
    pier
    Level 23  
    sq3evp wrote:
    Nice workmanship - your own design as a whole? What is displayed on the LCD?

    The design of the power supply is from Electronic Lab, as I wrote. Mine is the tile design and all the rest.
    You can see what the LCD displays, maybe the current value with an asterisk requires some explanation. This is the value of the set current limit.
  • #15
    ElectroTom
    Level 25  
    The performance of the professor. I am asking for a diagram of the automatics of transformer winding switching.
  • #16
    pier
    Level 23  
    ElectroTom wrote:
    The performance of the professor. I am asking for a diagram of the automatics of transformer winding switching.

    Thanks.

    Switch diagram taken from the electrode at the end of the topic are my suggestions.
  • #17
    zybex
    Helpful for users
    pier wrote:

    It started with the fact that I fell into my hands ups and in it quite a large transformer, 2x15V ~ with power I guess 650W. Additionally, it has a 22V ~ winding used for an auxiliary power supply. Designation of the transformer S 650/4 R11.

    Certainly, this transformer is not so powerful, but it is enough for this power supply. If there was so much power, it would be worth doing a "soft" start.
    I would like to add that the "650" is the power of the UPS for which it was produced. I read somewhere on the net that DTW 1200 has a power of 700W. I once sold a DTW 300 transformer here as 120 or 150W, because I found this information on the net then.
  • #18
    pier
    Level 23  
    zybex wrote:
    pier wrote:

    It started with the fact that I fell into my hands ups and in it quite a large transformer, 2x15V ~ with power I guess 650W. Additionally, it has a 22V ~ winding used for an auxiliary power supply. Designation of the transformer S 650/4 R11.

    Certainly, this transformer is not so powerful, but it is enough for this power supply. If there was such a high power, it would be worth making a "soft" start.
    I would like to add that the "650" is the power of the UPS for which it was produced. I read somewhere on the net that DTW 1200 has a power of 700W. I once sold a DTW 300 transformer here as 120 or 150W, because I found this information on the net then.

    That's why I wrote 650W, I guess. It's hard to find the actual parameters of these ups. I think that the 8-10A from this is the optimal maximum that can be taken.
  • #19
    zybex
    Helpful for users
    By the way, luck with the UPSs, I obtained a Polish transformer from Sigma with the designation TF300SC. Typical EI core with dimensions as 40VA transformer. Here I found a short mention of him https://www.elektroda.pl/rtvforum/topic805069.html.
    So these numbers do not refer to the transformer power for sure. If that "650" of yours works, that's fine.
  • #20
    CMS
    Administrator of HydePark
    Transformers in most UPSs have a power given as "UPS power" but first not in Watts, but in Voltoamers. Secondly, the vast majority of UPSs are designed for very short operation, usually 2-5 minutes under full load. However, there are UPSs with the possibility of connecting an external battery pack and such can work with a full load for even hours.
  • #21
    krychast
    Level 20  
    krakarak wrote:
    You write that the tiles are made in Asia, which is what? Did you receive etched, drilled plates with solder mask and soldered everything yourself or did you receive plates with soldered elements? ...

    What's wrong with that? Iron manufactory and the waste of time on making pcb at home is slowly missing the point since the Chinese do it for ridiculous money. Was the housing also to be bent or welded from sheet metal?
  • #22
    krakarak
    Level 41  
    krychast , try to read it comprehensively and as it is written, without searching for overtones and malice in a simple question ... After a month you took bites ...
    And I asked because the boards are very nicely made and the elements are soldered, so if I got the answer that he did it myself, I would praise it and ask how he did it and what, for I was curious. I have never looked so pretty.
  • #23
    zgierzman
    Level 30  
    krakarak wrote:
    And I asked because the tiles are very nicely made


    You know, your question was not so obvious, because for years ordering tiles from a Chinese costs literally pennies, and you get double-sided tiles with guides, solder mask and descriptions in the amount of 10 pcs.
    At the moment, 10 pcs of double-sided PCBs in the size of 10 x 10 cm cost $ 4.90 plus shipping. Any color of soldermask and descriptions.
    It would seem that making tiles in China is a choice of "first contact", so you can try to over-interpret your question and look for hidden content and maliciousness ...

    Power supply 0-30V, 0-8A again Electronic Lab