Bench Power Supply

by badarsworkshop

42K39056

Intro: Bench Power Supply

In this instructable I will be showing you how to build a bench power supply using some simple off the shelf components and a custom 3D printed cases. The goal was to make a compact and sleek looking power supply which is powerful enough for most applications.

This is my first project video on my youtube channel so consider giving it a look and subscribing if you are interested in more videos of the kind. This one is pretty simple as my focus was the video making part of it but the videos to come will be more original and involved. So look forward to those.

Youtube Channel: Badar's Workshop

Facebook Page: fb.com/badarsworkshop

STEP 1: Parts Required

You will need the following parts for this build

  1. Power Supply Module 30V 5A AliExpress
  2. Power Supply 36V 1.4A 50W DigiKey
  3. IEC Panel Jack AliExpress
  4. Banana Jack Posts AliExpress
  5. Power Switch AliExpress
  6. Voltage Regulator AliExpress
  7. 12V 40mm Fan AliExpress
  8. Connector Kit AliExpress
  9. 3D Printed Case

STEP 2: Designing the Case

I designed the case in SolidWorks. Before getting started, I glued some nuts in the housing of the power supply so that I can secure it with the plastic housing. The idea was to make a shell to house everything but not to enclose it entirely so I designed it with an open base.

I made all the measurements using a caliper and designed the case using a simple geometric approach. No fancy curves or anything, just something that is easy to print and ergonomic. That is why I angled the interface at a 45 degree angle to make it easy to see and use.

I paid attention to air flow because under load, the power supply will get warm and I dont want to worry about melting the plastic housing. So I incorporated a fan at the top and a exhaust grill on the side. The bottom has some open area too. The idea is that air will enter from the top and take the heat from the power supply and the module as it exits from the side and bottom.

One more thing to take into consideration while designing is that how will it all go together. Its easy to overlook size of the components while designing because you cant visualize the components. So I had to take account of connectors so that I leave just enough room for easy assembly and disassembly.

STEP 3: 3D Printing and Reprinting

I printed the case with an orientation that would give the best surface finish. It took me a couple of tries to get it to print right as the model would detach from the bed while printing. After some trial and error, I figured out the right combination. The trick was to heat the bed just a little bit to 30 C and apply the painters tape on a clean surface.

The first successful print revealed some issues with hole placement for the mounting screws and some size issues. That is usually the case with 3D printed case and I was expecting it to be like so. I made the corrections and reprinted it. Everything seemed to fit right so I went ahead with assembly.

I have attached the stl file and the Solid Works file so feel free to modify it however you like it.

Important Note: I have one extra 3D printed case which I will be giving away to one of you guys who wants to build the power supply. All you have to do is subscribe to my channel and send me a message. I will ship it to the first person who reaches out to me. (US Only)

STEP 4: Assembly

The good thing about working with custom 3D printed cases is that if you put thought into the design part of it, assembly can be very simple and satisfying. Just follow the simple steps:

  1. Secure the banana posts on the front panel using the nuts and washers that come with it.
  2. Screw in the IEC Jack on the back using M4 screws.
  3. Pop in the power switch.
  4. Start the wiring by crimping spade connectors to the appropriate length wires.
  5. Solder the fan regulator to the output line of the power supply.
  6. Set the output to 12 V and then solder the fan to the output.
  7. Screw in the fan using M4 screws and glue in the regulator.
  8. Finish up the wiring and connect the power supply and power regulator.
  9. Screw in the power supply using M3 screws and finish up by sticking some rubber feet.

The wiring is pretty simple so I wont go through drawing up a schematic. The AC input of the power supply is connected to the IEC jack through the power switch. The output of the power supply is connected to the input of the power regulator and the fan regulator. The output of the power regulator is connected to the banana jack posts. And the output of the fan regulator is connected to the fan.

STEP 5: Testing

The power module is very versatile as you can adjust both, the voltage and the current. It can be used to test circuits and charge batteries among other uses. I tested it running on max load for a few hours and didn't notice any thermal effects.

STEP 6: Conclusion

I hope you found this simple project interesting. This project was mainly aimed at getting a start into the video making part of projects as I plan on building a youtube channel.

Let me know what you think in the comments and give me some feedback about my video. I will be making more videos soon.

If you are making a similar power supply and need a 3D printed case, subscribe to my channel and send me a message. I will send it to the first person who reaches out to me. (US Only)

45 Comments

pemazzei 4 years ago

Hi, can I have the correct size of this plastic box? I don´t have 3D printer here in Brazil... I will try to make in aluminum sheet. Thanks.

cemdede 5 years ago

Do you have any ideas about improving the gel run-time by using a "high purity titanium-niobium superconductor sheet" for the gel tank?

nlkirchn 5 years ago

I just received the final part for the power supply and another issue is the bosses on the inside of the case for the fan power supply are backwards.

nlkirchn 5 years ago

Unfortunately the link to the PSU gives you a unit that is smaller than your original the specs are the same but the unit is significantly smaller so it makes it hard to mount it in the case. I've attached the dimensions.

badarsworkshop 5 years ago

I am sorry about the incorrect link. I actually didnt purchase the power supply unit. I salvaged it from an electronics recycling place. So I just searched for it and put up what looked to be the same thing. I found exactly what I used and updated the link but the one I used is pretty expensive as it seems to be of very good quality. You can modify the housing to fit your requirements. I have supplied a SolidWorks file. If you want a different format, I can export it in a different format and upload that. Once again my apologies for the mishap.

Zenmaniac 5 years ago

I agree with nlkirchn. The power supply in the video is LS50-36, which shows at DigiKey as 3.90" L x 3.80" W x 1.40" H (99.1mm x 96.5mm x 35.6mm). The one in the link (which I just received today, so saw nlkirchn's post too late) is 79mm x 110mm x 36mm. Looks like a spacer or an updated case will be needed. :-(

Zenmaniac 5 years ago

Your video shows a green connector, but it doesn't show up in the parts list or in the parts photo. Can you clarify? Does it come with the Power Supply Module, or is it a separate part? Thanks!

badarsworkshop 5 years ago

Yes it comes with the RD Voltage Regulator.

Zenmaniac 5 years ago

Perfect! Thanks -- I should be good to go... whenever AliExpress cares to deliver. ;-)

pacav69 5 years ago

the position of the output terminals should be located away from the adjustment control to provide better access.

Instructor477 5 years ago

I was just scanning
this instructable to see if I might be interested. I get that you
are focused primarily on the creation of the printed case, but I
wound up with a lot of questions about the electrical guts of the
project. The materials include "Power Supply Module 30V 5A",
"Power Supply 36V 1.4A 50W", and "Voltage Regulator"
(the supplier's terms?). The instructions by contrast refer to "fan
regulator", "power supply", and "power regulator"
(your terms.) The correspondences between these two lists is not
immediately obvious.

If I had to guess, I
would pick "Power Supply 36V 1.4A 50W" (probably a fixed
voltage switching supply) as the principal DC source (the larger unit
in the perforated metal case?). Then the "Power Supply Module
30V 5A" is probably an adjustable buck converter (the smaller
bare module, being utilized here at a confusingly small fraction of
its rating) as the "fan regulator". The real sleeper then
would be the "Voltage Regulator" (aka the power
regulator?), which appears to combine both the front
panel/controller/user interface function with another adjustable buck
converter in one module. Did I get that right?

I also didn't see
where in the assembly instructions the "power regulator"
gets installed in the case and how it is fastened.

Would you consider
adding more detailed (and consistent) descriptions of your electronic
modules and, if not a schematic per se, then perhaps a block diagram
instead for the benefit of future readers?

badarsworkshop 5 years ago

Thanks for the detailed comment. You are right that the terminology can use improvement. I will go over it again and define specific terms for each component.

badarsworkshop 5 years ago

You are right but since it was what I had on hand so i went with it. But if I were to build it again, I would use a different power supply. Yours looks pretty cool.

Alex Gor 5 years ago

I understood. Thanks!

frarugi87 5 years ago

In step 5's picture you are putting your fingers around the cables, since you have to rotate the encoder with your right hand and there are the cables in between. Maybe having them under the display (in the non-45-tilted area) would have been a better choice, wouldn't it?

addison8019 5 years ago

This is cool, added to my "I'll make that one day" list :D

HankA4 5 years ago

Hi again bad ars tinkerer , say does your 5 amp model ask for a blocking diode on positive out to prevent back flow from capactive or battery charging ? Mine doe's I just mentally compensate the small difference . Almost perfect device.

theo67 6 years ago

So you made a box and put things in it. The power supply seems to be irrelevant. Nice video though.

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