Benchtop DC Power Supply with 2 adjustable outputs

Last crawled date: 4 years, 3 months ago

I was in need of a reliable power supply for my maker space. I need two adjustable outputs, constant voltage/current, and voltages from 3.3 up to 30 V. Having 5A was one goal as well.
https://www.youtube.com/watch?v=weG6X18faGc
BE CAREFUL! WARNING: Voltage from mains is dangerous and can cause serious injuries or death. BE CAREFUL or ask a professional to help you with the wiring.
Bill of materials:
1x Mean Well AC/DC LRS 200/36 https://www.amazon.de/gp/product/B07FM9T9ZV
1x C14 socket with switch and 6A fuse https://www.amazon.de/gp/product/B01H5MK3OI
2x DC-DC https://www.amazon.de/gp/product/B07DWX96M9
1x Buck converter https://www.amazon.de/gp/product/B077VW4BTY
1x 120mm fan, 12V https://www.amazon.de/gp/product/B002KTVFTE
7x Cable shoes 4.8x0.8 https://www.conrad.de/de/p/vogt-verbindungstechnik-3805-67-flachsteckhuelse-steckbreite-4-8-mm-steckdicke-0-8-mm-180-unisoliert-metall-1-st-1226359.html
2x fuse holders https://www.conrad.de/de/p/tru-components-tc-r3-12-sicherungshalter-passend-fuer-feinsicherung-5-x-20-mm-10-a-250-v-ac-1-st-1587496.html
2x Fuses 20x5mm, 6.3A https://www.conrad.de/de/p/eska-522525-feinsicherung-x-l-5-mm-x-20-mm-6-3-a-250-v-traege-t-inhalt-10-st-533556.html
1x Binding post 4mm, green https://www.conrad.de/de/p/cliff-tp-1-polklemme-gruen-15-a-1-st-705938.html
2x Binding posts 4mm, red https://www.conrad.de/de/p/cliff-tp-1-polklemme-rot-15-a-1-st-705914.html
2x Binding posts 4mm, black https://www.conrad.de/de/p/cliff-tp-1-polklemme-schwarz-15-a-1-st-705902.html
15x Cable shoes M3.5 https://www.conrad.de/de/p/conrad-components-93014c221-gabelkabelschuh-1-50-mm-2-50-mm-loch-3-7-mm-teilisoliert-blau-100-st-745312.html
4x screws Cylinderhead M4x20
2x screws Cylinderhead M4x15
1x screw Cylinderhead M4x6
25x screws Cylinderhead M3x20
2 screws Cylinderhead M3x16
5 screws Cylinderhead M3x12
2 M3 nuts
Heat shrinking tube, 5mm diameter, about 250mm
2.5 sqmm wire, 3 colors, rated for at least 6 A
solder stuff
zip ties
4x selfadhesive rubber feet
3D print all the parts once each. Forget about support, rafts, brims etc. Just 3 shells in each direction, and 20% cubic infill. I used standard PLA from https://dasfilament.de, and the stuff printed well on my Prusa I3 Mk3. If you have a printer with less then 250mmx200mm print bed, this thing might not be for you.
Once you have the printed parts available, and sourced the list above, this was my way to go.
BE CAREFUL! WARNING: Voltage from mains is dangerous and can cause serious injuries or death. BE CAREFUL or ask a professional to help you with the wiring.
Before you start make sure the voltage switch at the Mean Well is set to the voltage your mains are running on.
1.) Mount the Mean Well to the bottom, fix it using M3x20. The screw terminals point to the right
2.) Mount the back to the bottom using M3x20. Use M4x15 to mount the Mean Well to the back
3.) Mount DC/DCs, all the binding posts and the fuse holders to the front. From left to right the fuse holders and binding posts go like this: red, fuse holder, black, green, black, fuse holder, red
4.) Prepare 10cm wires to connect the OUT- of the DCs to the black binding posts, one side just with some solder on it, other side with cable shoe M3.5. Use heat shrink to cover the cable shoe
5.) Prepare 10cm wires to connect the OUT+ of the DCs to the fuse holders, both sides just with some solder on it
6.) Prepare 6cm wires to connect the fuse holders with red binding posts, one side just with some solder on it, other side with cable shoe M3.5. Use heat shrink to cover the cable shoe
7.) connect fuse holders and red binding posts using the cables from 6.)
8.) prepare 1 cable 15cm long, both sides with cable shoes M3.5, convered with heat shrink
9.) use M4x6 and connect the cable from 8.) to the front side of the Mean Well, connect the other end to the green binding post
10.) prepare 2 cables 20cm long, 2 cables 24cm long. One side just with some solder, other side with cable shoe M3.5. Use heat shrink to cover the cable shoe
11.) Connect Mean Well 36V outputs and DC/DCs. Do not confuse Voltage and ground!
12.) Prepare 2 15cm wires, One side just with some solder, other side with cable shoe M3.5. Use heat shrink to cover the cable shoe
13.) Use cables from 12 to connect the buck converter and the Mean Well 36V outputs
14.) Mount the DCHolder to the back using 2 M3x20 screws, pointing inside the case. Do not confuse voltage and ground
15.) Mount the C14 socket to its place of the back. Secure it using M3x16 and the M3 nuts
16.) Prepare 1 cable 20cm, having Cable shoe 4.8x0.8 on one side, and Cable shoe M3.5 on the other side, and cover the cable shoes with heat shrink. BE CAREFUL!
17.) connect this cable to the earth of the C14, and to earth of the Mean Well. BE CAREFUL!
18.) Prepare 2 cables 20cm, having Cable shoes 4.8x0.8 on one side, and Cable shoes M3.5 on the other side, and cover the cable shoes with heat shrink. BE CAREFUL!
19.) Connect Mean Well 240V and the switch of the C14 socket using the cables from 18.)
20.) Prepare 2 cables 8cm, having Cable shoes 4.8x0.8 on each side, and cover the cable shoes with heat shrink. BE CAREFUL!
21.) Connect the connector of the switch and the left connectors of the C14 socket itself using cables from 20.) BE CAREFUL!
22.) Doublecheck all the wiring, you can use a multimeter. BE CAREFUL!
23.) Doubecheck you can measure connected earth between C14 earth, all M4 screws and the green binding post at the front. BE CAREFUL! Doublecheck not to have a connection from any of the C14 connectors to any 36V connectors of the Mean Well
24.) Mount the right case to the case, use 9 M3x20
25.) Mount the left case to the case, use 9 M3x20
26.) Doublecheck you did not kill any wires when screwing the stuff together. BE CAREFUL!
27.) Connect the power cord, and switch the device on using the switch at the C14 socket. BE CAREFUL not to touch the mains!
28.) Trim down the buck converter to deliver 8-10V
29.) Switch your power supply off, and remove the power cord. BE CAREFUL!
29.) Solder the fan wires to the outputs of the buck converter without confusing ground and voltage. If there is a socket at the cable, remove it. If there are 3 cables, use the one marked ground as ground, and the middle one as voltage. Mount the buck converter to the DCHolder using zip ties
30.) Mount the fan to the top, using the screws delivered with the fan. Make sure the fan is blowing the air OUT of the case.
31.) Close the case using the left M3 screws. Attention: on the fans side use the shorter screws!
32.) Connect the power cord, switch the power supply on, switch the DC/DC on, set a voltage to each and measure the outputs. Are they delivering the right voltage?
33.) Mount the rubber feet to the cases bottom
Done!
Again, BE CAREFUL! WARNING: Voltage from mains is dangerous and can cause serious injuries or death. BE CAREFUL or ask a professional to help you with the wiring.