3 Axis CNC router

**JoeHarris** · 27-04-2017

Originally Posted by Neale

Only comment (if you have a chance to make any small mods at this stage) is to add a few more sets of terminal contacts for the output, all wired in parallel. This allows you to run separate power feeds to each stepper driver, rather wiring them daisy-chain fashion, and it's easier than trying to stick three big wires in the same terminal. Not sure if it really make a difference in our class of machine but it is generally considered good practice not to share high-power connections between devices, and it's a lot easier if you have multiple terminals available. Might be able to put multiple spade terminals on each of your contacts, though?

Thanks Neale, The terminals are overkill in terms of size and will take two cables each but as I've shown on the circuit diagram the plan is to take one feed from the terminals on the power supply to some din terminal blocks with a jumper bar to provide as many as I need...

**Neale** · 27-04-2017

Sounds fine. My PSU was originally bought from Zapp, although I have now changed the transformer in it, but it came with three pairs of output terminals already. Then I fitted it in a control box with four stepper drivers...

Must confess that I didn't actually put a wiring diagram together for mine, just some sketches to work out roughly what was needed. Then I set to work with a pile of cable reels, big box of ferrules and crimping tool, and quite a lot of black coffee. Don't try this one at home

Still, it does seem to work OK.

**JoeHarris** · 27-04-2017

Originally Posted by routercnc

If you got 50V in post 373 at the rectifier then so long as capacitors are correct way around then should work . . . Only one way to find out

yep crack on!

**Desertboy** · 06-09-2017

Originally Posted by JoeHarris

Excellent build Joe read the whole thread from beginning to end yesterday! The PSU bit is a real god send to me right now as building my own and you really helped demystify it for me, thanks ;)

I have a quick question what thickness Red/black wire do I need to get to connect from the rectifier to the capacitors then to the output?

Also where did you get those terminal blocks I could only find them in China or America although I found a suitable replacement I think with barrier terminal blocks.
https://www.rapidonline.com/truconne...-block-21-3073

Thanks
Desertboy

**JoeHarris** · 06-09-2017

Originally Posted by Desertboy

Excellent build Joe, the PSU bit is a real god send to me right now as building my own and you really helped demystify it for me, thanks ;)

I have a quick question what thickness Red/black wire do I need to get to connect from the rectifier to the capacitors then to the output?

Thanks
Desertboy

Glad it helped - I was pretty scared of this part of the build!! Clive and Dean were super helpful as usual. I think I used 2.5mm tri-rated, I'll try and remember to check for you when I get home.

**JoeHarris** · 06-09-2017

Originally Posted by JoeHarris

Glad it helped - I was pretty scared of this part of the build!! Clive and Dean were super helpful as usual. I think I used 2.5mm tri-rated, I'll try and remember to check for you when I get home.

In fact you can see in the pictures it says 13AWG which is 2.5mm. It hasn't seen any hard use yet so remains to be seen if it will work well, but it switches on without killing me or catching fire, so that's a start!

**Clive S** · 06-09-2017

Joe A picture paints a thousand words I tend to point people to your P/S vids (if that is ok) as they are an excellent way to show how easy they are to build. There is one point and you have it correct is that you must not but an earth (ground) to the bolt on the top of the transformer that runs through it. It is ok at the bottom end ie the plate.

**Desertboy** · 06-09-2017

Originally Posted by JoeHarris

In fact you can see in the pictures it says 13AWG which is 2.5mm. It hasn't seen any hard use yet so remains to be seen if it will work well, but it switches on without killing me or catching fire, so that's a start!

If you do die can you get some one to send me a PM saying get 4mm wire lol ;) I missed that but actually managed to read the part number off the connector blocks and find them on ebay lol.

**Desertboy** · 06-09-2017

Originally Posted by JoeHarris

Glad it helped - I was pretty scared of this part of the build!! Clive and Dean were super helpful as usual. I think I used 2.5mm tri-rated, I'll try and remember to check for you when I get home.

It was Clive that put me on to you and convinced me I could build the supply. It looks really simple but at the same time I can totally understand the fear lol I was petrified but now I think it'll be relatviely easy just trying to work out if I can cram this into an ATX power supply casing if I move the fan externally and add a 2nd fan either so it blows in one side and sucks out the other.

I want to try and fit the stepper drivers and self build PSU in a PC mini tower case with a whole pc as well.

I have a mini 80plus PC power supply I can fit somewhere in the case (It's about 1/3 size of ATX) and I think I can put the AM882 where the drive bays are. I could ditch the Hard disk and run from a fast USB flash drive or SD card it will be quick enough for linuxcnc. Or I could mount the hard disk somewhere else. I think as long as the PSU's extract their heat to the air and I add a bathroom extractor fan as well for the pc and stepper driver waste heat I'll be ok. Maybe add an active intake as well sucking air a distance away from the extraction point.