2 power supplies per computer. Connecting the second TX power supply to the computer
In the last article, we looked at the theoretical features and circuit of two power supplies from a PC, with the aim of summing up their power. Now it's time to conduct practical tests. To do this, we take two ATX blocks of the same power (although the number of blocks may be more), in my case these are two 450-watt power supplies.
We connect the load (I found only a 35-watt incandescent lamp on hand). We connect the light bulb to the block and measure the current consumption. It is at the level of 2.42 A. I happened to have a PWM regulator circuit at hand, and with its help we reduce the current to the level of 2 A for ease of control.
On one of the blocks the output was 11.66 volts, on the other 11.89 volts.
As you can see, the difference is 0.23 volts.
We connect two blocks in parallel through decoupling diodes and measure the current consumption at each of the outputs of the ATX blocks.
The pointer device is turned on at the limit of 2.5 A. As you can see, from the block with a lower voltage the current consumption is only 200 mA, while from the block with a higher voltage it is 1.8 A. It took on the entire load. Let's calculate ballast resistors. They should be 10-15% of the input load resistance. Now the question is: how to find the load resistance? To do this, you need to know the maximum current consumed by a given load. For example, we know that our supply voltage is 12 volts. The current consumed by the load is 2 A. We take the formula, which should be familiar to all radio amateurs: R=U/I . We substitute our numbers 12/2 and get 6 Ohms. Then we take 10% of the result obtained and get our 0.6 Ohm ballast resistor. This resistor will limit the current drawn from a single ATX unit. We substitute resistors in our circuit and see what happens:
As you can see, the current is smoothly distributed between the two blocks. We measure the voltages that come from each block (by first connecting ballast resistors to the blocks, and then diodes, which makes no difference in this circuit).
It can be seen that the voltages have equalized.
Let's now try to slightly increase the load consumption.
The load is distributed almost equally. In this way, you can connect three or more standard PC ATX units in parallel. In practice, it turned out that if you parallel only two blocks, you can get by with only one resistor in the block circuit with a high voltage. It is selected experimentally so that the consumption currents from each of the blocks are equal. You can do without resistors, but to do this you need to open the power supplies and, using the selection of resistors in the voltage divider circuit (if the microcircuit is TL494, then they are connected to 1 leg), adjust the voltages in the units to the most identical value. Then they are simply paralleled through diodes of appropriate power. The picture shows what came of it.
By paralleling two 450-watt power supplies through diodes and shorting their outputs to 12 volts with a simple steel wire, we managed to heat it up to red hot.
Unfortunately, there is no 50 A ammeter to clearly show the current consumed. On a digital multimeter with a limit of 20 A, the readings went off scale and the probes began to melt. With such a closure, one block immediately went into defense. Author of the article: Ksyunya (Voitovich Sergey).
Sometimes it happens that a computer power supply does not “pull” the load applied to it. In this case, it is easier to buy a more powerful power supply. But there is a second option - install another power supply in the system unit. This will only make sense if you have an unnecessary block at hand, as in my case, the TX block.
First, we find a relay that will start the second power supply when the main one is turned on. At hand was this relay from 1992 from a TV with remote control:
Of course, you can use any relay whose winding is designed in the range of up to 12 volts, the conducted current is at least 220V 5A, for example this:
Now let's talk about how to determine what specific relay legs belong to.
Using an ohmmeter, we find 2 relay legs on which the resistance will be displayed. This is a winding, low voltage will be supplied to it to drive the relay.
We've sorted out the relay, now we're starting to remake the main power supply. We take it out of the system unit, unscrew it, remove the board and put it aside. We fix the nest in a convenient place:
After inserting the socket, we move on to the board. To make it easier to connect the relay, I installed the connector:
It will be possible to simply solder the relay winding on the back side of the board with one end to the common wire of the power supply (black) and the other to +12V (yellow)
While there is still a chance, lubricate the fan and remove dust (if this is required, of course). Then you won’t have to disassemble the unit again due to the loud hum of the cooler or overheating. For ease of further maintenance, it would be a good idea to install a mains power connector. Manufacturers often skimp on this and don’t install it; it’s not very convenient; it will be necessary to turn on the soldering iron every time if you need to disconnect the board.
Let's move on to installing the relay. The ideal place to place it is on a board that is soldered to the network connector. To prevent anything from shorting out in the future, everything needs to be well insulated. To do this, place a plastic rectangle proportional to the board on hot-melt adhesive, not forgetting to solder the wires first:
We solder the relay contacts to these wires, having previously soldered the winding wires and output wires:
We finally fix the relay with hot glue and solder the output wires to the socket:
We put the main power supply in place and begin to remake the additional one. We disassemble it and remove the now unnecessary network connectors by directly connecting the power cord to the board:
Now you need to install the second block into the computer case. The hard drives were moved higher:
And I put the power supply in their place:
All. We connect the second power supply to the socket of the first and check.
Now, when you turn on the main power supply, the additional one will start.
TX - old type power supplies. The main difference between ATX and TX is that they have different motherboard connectors and different startup methods.
For TX blocks, startup occurs by closing the contacts of the power cord, which is located on the front panel of the computer. To start such a power supply, you just need to apply mains voltage to it, as I did using a relay.
When ATX units are connected to the network, they do not start; the standby power is turned on first. To start such a unit, you need to short-circuit the green and black wires in the motherboard connector. This can be done using a relay (not forgetting, of course, to connect the second block to the network) or connect the green wires of both blocks in parallel. In this case, the motherboard will give both power supplies a turn-on signal.
To avoid failure of your power supply, it is important to connect a small load of 5% of the rated load to all power lines.
You can read more about the differences between power supplies
Guys, I have the following question for you: is it possible to hang on a second power supply unit that is 250 watts (a very old power supply unit), attach 4 satash screws to it, each 1 TERABYTE, 1 flop, a couple of CDs and fans??? The question is, will a 250 watt power supply withstand such a load? I just don't know how to do such calculations. And I still don’t understand which black wires need to be paralleled?? Are those that go to the main 24-pin connector on molexes?? I still don’t understand from the description of the posts above. If anyone can post a diagram for connecting the black wires please. Another question will be how many power supplies can be connected to the green PS_ON wire, even though ground is supplied to it, but it passes through the motherboard and I assume there is some kind of relay-type device installed in it, since when you press a button (not a toggle switch), there is constant power green wire. As for starting two power supplies at the same time by using the relay from the posts above, as I understand it, they use a car relay and it is not clear WHAT wires it is POWERED (whoever made such a connection, please post the diagram in more detail) and it would also be nice to indicate what brand of relay is used in this case .. (the point is that someone who has already done this would suggest which relay is better “more reliable” to use in this case) And also connect 2 power supplies only using the green wire from the posts above, as I understand it, only 12 and 5 volts will be used and 3, 3 volts will remain without load on the second power supply and this may somehow negatively affect its service life. Then tell me which one and how you can put a load on them. Please, someone send me the diagram in more detail about what and which ones need to be powered on the Main 24-pin connector. And the question is, if suddenly 2 power supplies burn out and start to produce a voltage that is not at the nominal level, how to protect the computer, as I understand it, the computer goes into shutdown when voltages that differ from those required by the system begin to be supplied to the motherboard. BUT since the second power supply will not be powered to the motherboard but only to the screws and CD, how then can the computer protect itself from incorrect voltages? connection by paralleling all the wires through diodes is an interesting thing, but it is not suitable for those who do not use electronics; you need to select diodes and then adjust the final voltage at the output; this is not something every user can do, and the design itself becomes much more complicated. And as for voltage imbalances, how will this be displayed on the equipment, since the second power supply will only turn screws and CDs? ? how important will it be for the HDD if the voltage on it is, say, a little too low or too high (in the sense that the voltage is suitable for the voltage rating, but slightly different from the power supply of 1 PSU, say, by 0.2 volts?? MY PSU equipment (first) POWER MASTER SWITCHIG POWER SUPPLY MODEL FA-5-1 (300W-PEAK LOAD) the second power supply that I want to connect 4 HEAD screws 1 TERABYTE, 2 CD-RW, Flop, 250 Watt from Pentium 3 there is not even a connector for additional power supply for the processor brand Name of the model I can throw off later if it is will be important :) AMD Athlon 64 CPU, 2000 MHz (10 x 200) 3000+, Initial frequency 2000 MHz (I don’t overclock) I measure it with the motherboard utility, it sags by +12 Volts, +12.20 is requested, but I often get +12, 75 when loaded with applications drops to +12.65 Volts. Motherboard Asus K8N4-E (motherboard ID 10/21/2005-NF-CK804-K8N4-EB-00) Physical memory Total 767 MB now 3 dies of 256 MB each with a timing of 166 GHz. I'm thinking of replacing it with two gigs, that is, each die is 1 gig. on and I leave one at 256 MGB with a timing of 200 GHz. Vidyuha PCI Express x16: nVIDIA GeForce 6600 PCI-E Sound Realtek ALC850 @ nVIDIA nForce4 (CK8-04) - Audio Codec Interface PCI HDD Disk #1 - WDC WD600BB-75CAA0 (55 GB) and Disk #2 - ST380011A (74 GB) for some reason they often heat up, the temperature rises to almost 50 C. 2 CD-RWs and 1 flop. I apologize in advance for typos or too long a post. I don’t often communicate on forums and don’t have a clear idea of how to communicate here. Basically, I only had to communicate online in DS++.
Dual PSU Connector Adapter
This is just the modified copy of the Dual PSU Connector that I assembled (photo 4).
Homemade Dual PSU Connector adapter
As you can see, the adapters are different. In my version there may be an excessive, but in my opinion not excessive, number of COM wire connections. I hope that the reliability of the adapter of my assembly is an order of magnitude higher.
I would also like to note the positive aspects of this connection method:
1) There is no need to unwind the power supplies or cut off the insulation from the wires, therefore the warranty on the power supplies is not violated. The benefits are obvious.
2) Large financial investments are not required. In my case, the costs were $1.5, excluding the cost of tin, rosin, electricity and time spent.
3) A fairly reliable contact is achieved between the COM conductors of the two power supplies.
4) Economic effect
Minuses:
1) In case of problems with one of the power supplies, the second one does not turn off.
The disadvantage could be corrected by using a circuit with three relays, but having estimated how much the number of connection points would increase, and therefore the losses at the tin-copper transitions/relay contacts/solder quality, I abandoned this option.
And let's briefly summarize. To implement this idea, you must have the following:
- one 20+4pin plug with a piece of wire ~20cm, in my case - cut off from the burnt power supply;
- two 24pin sockets, in my case, unsoldered from burnt motherboards;
- soldering iron (preferably no more than 40W), tin, rosin - to taste;
- one free evening.
For practical implementation: take a plug, estimate the required length and cut off the excess wires (photo 5).
Components of the Dual PSU Connector adapter
The shorter the adapter wires are, the less loss there is. I believe that you should not leave more than 15cm, but this is my personal opinion, dictated by logic, ease of use and common sense, not confirmed by practical experience.
We use part of the remaining wires, about 5cm long, to connect the COM and PS-ON wires of one 24pin socket to another.
Then everything is simple - we strip the ends of the wires from the plug, tin them and solder them to the necessary points on the sockets, and so on many, many times. We isolate, check the correctness of assembly and go connect.
The placement of the second power supply in the case, on the case, or next to the case is limited only by the length of the wires, the size of the case and your imagination. I got it like this (photo 6):
Two power supplies included in the system
Not the best option, but given the size of the case, the length of the power supply wires and the ATX form factor of the motherboard, there was no choice.
I also additionally connected the case of the second power supply to the computer case through a copper terminal from some industrial device and 2 bolts.
And now a little about connection. Combining all the knowledge gleaned from reading forums and documentation for the above-mentioned building, I came up with a few simple connection rules, which I used myself:
1) Only the motherboard needs to be connected to the main power supply, including all the necessary additional power cords (4pin and 4pin molex on my board).
2) You can relatively safely connect all drives to the second power supply, and with little risk - an additional power connector for the video card (in the case of the GeForce 8800GS video card, this is about 6-7A along the +12V line). It is strongly not recommended to power additional power connectors on the motherboard from a second power supply.
3) The load on the +5V and +12V lines of both power supplies must be distributed more or less evenly, otherwise there may be problems such as the power supply overestimating any of the voltages, or failure of inexpensive power supplies. As a last resort, you can hang a light bulb of a suitable rating, or a couple of fans on an underloaded line.
The system has been working for me in this form for a little over a month. There are no problems or complaints about instability in work. Freezing at system startup never happened again. The second power supply is the new TARGA PT-400CF 400W.
I also want to note that the overclocking potential of the processor has not changed, but stability has appeared at a frequency of 2900 MHz at a voltage of 1.55 V instead of the previously used 1.612 V. Standard real frequency 2000 MHz (1.3V), stable overclocking up to 2900 MHz.
That's basically all. Thank you all for your attention. Also, my thanks to the copyright holders for the 3 fragments of photographs that I used in this article.
It remains to add that everything you may do after reading this article is done at your own peril and risk, and I am not responsible for possible negative consequences. The information is provided for informational purposes only.
With suggestions and wishes - welcome to
I have two farms that have 2 power supplies, they are connected to each other by synchronizers to run two power supplies. I have three different types, but only two are in use, and the third are in storage. On Aliexpress they cost 200-300 rubles, and in Russia the price is about 500 rubles.
At the farm, on the main unit there are only 2 6-pin cables for video cards, and I don’t have Molex-6-pin adapters. Therefore, I connected a 450 W power supply as an auxiliary one for one video device that requires additional power.
The first version of the synchronizer
This one looks like a bunch of black wires. One end is connected to the motherboard, and the other to the power supplies. The main power supply is towards the end, where there are a lot of wires, and where there are two wires to the specific (auxiliary) one.
As soon as I was able to get to the wires, I took a picture. It's hard for me to get to this place)).
The second option is a sata and 24-pin synchronizer
The other looks like a chip strip and two synchronization inputs. Connect the main power supply to the motherboard, from the main one connect the molex 4-pin to the bracket. Plug an auxiliary power supply into the 24-pin socket on the bracket. I think this is the simplest of all three.In the description from a seller in China, I found recommendations that it should not be equipped with a power supply larger than 800 w. I also assume that the other options are not designed for high power. But you need to check this with the seller or look for information on the Internet; I have not yet found information on what power is permissible for them.
Third - with Molex and Sata input
I haven’t tried it, it’s lying around while it’s waiting for its mining rig. If I understand correctly, then here too, only the main one is stuck into the Sata entrance. I don’t understand why Molex is needed, if anyone knows, write in the comments. It is possible that there was an alternative choice. But I do not recommend connecting to SATA and MOLEX at the same time!There is also a work light and on/off light in the lower right corner.
Both of the first ones work great and haven't caused any problems yet. Maybe later there will be glitches or some problems, but for now we live in peace.