Replacing a PSU / changing some loads

[enpassant]

Hello folks, hoping for some help on a project I'm doing at home involving my 3D Printer (...it's 2019... who doesn't have one of these things at home?!)

It has a 24V 25A power supply providing the juice but it's a cheap LED driver and it's noisy - it's just the fan but as it's in the living room, it's annoying.

I've bought a new PSU to replace it with but before I hook it up I want to make sure it's not going to snap, crackle and pop! I'm looking to replace it with this silent, fan-less, Meanwell HLG-600H-24A [600W], please see:





Currently everything is connected to a common rail on the power supply (controller board, heated glass printbed via solid-state relay, 3x 24V fans, LED strip to watch it make stuff)

I am changing it slightly and am using some busbars to splits things up: I have +24V & -24V being supplied from the PSU and from there +12V & -12V busbars via DC-DC 24-12 converter, which I will run replace the 24V fans with 3x new 12V fans and a also new 12V LED strip. I've hooked this part up to the current PSU, please see:



The main reason for question is that the Meanwell PSU is a "single output" supply, which adds up as there's only 1x rectifier with + & - coming from, but as per the "mechanical spec" it has 2x 24V output cables and another with RC+/- & GND. I assume from the the diagram above these are simply in parallel and the RC cables I have absolutely not a clue what they're for, but since they're 5V and linked to some form of PWM control of the PSU I'll likely cut them back and ignore.

What I'm looking to do is simply connect the 2x positives to 1 busbar and the 2x negatives to the other busbar then provide the 24V stuff from there... and step-down the 12V as in the picture.

I assume, then, that it would become this:




The 3D Printer is rated as 600W peak but I don't know the exact specs for all the components. The controller board is 24V and directly supplies the DC stepper motors and the heated nozzle for melting the plastic. I don't have specs for the heated printbed but that's obviously the biggest contender for that power demand.

The output cables are 14 gauge, and a quick google gives me equivalent as 2.5mm2, but I'm not sure how accurate that is.

a. I'm unsure if each output cable would be able to take the 600W (in which case why have 2?).

b. What would the result be of joining the 2x +'s and the 2x -'s as above?

Should probably also mention the 3D Printer is >£6k and the PSU is fairly expensive, instead of the normal £30 on Amazon, it cost >£200, hence my reluctance to just plumb it in and hope for the best!

 

[Charlie_]

Why use a psu with dimming functions? Just a standard Meanwell dc power supply would do? Which would cost less.
Will there be good air movement around the psu?

 

[Bobster]

What's the spec of the PSU you are replacing?

Also, you've spent 6k on a printer, an possibly one of the most important components, you want to scrimp on?

If it is just 24V DC you need, I would have looked at an industrial PSU ~ 150quid.

This would include good filtering, voltage adjustment, over current protection, short circuit protection.

 

[enpassant]

Why use a psu with dimming functions? Just a standard Meanwell dc power supply would do? Which would cost less.
Will there be good air movement around the psu?

I'm not interested in dimming it - I want it simply as a 24V output. It will be enclosed but there will be 2x silent (well, so they say... they're as quiet as I can get anyway) 12V fans inside the enclosure. The PSU is fanless and cooled by free air convection, that's the main reason for it.

What's the spec of the PSU you are replacing?

Also, you've spent 6k on a printer, an possibly one of the most important components, you want to scrimp on?

If it is just 24V DC you need, I would have looked at an industrial PSU ~ 150quid.

This would include good filtering, voltage adjustment, over current protection, short circuit protection.

No idea, it's the one which came with the printer. It's a no-name 24V 25A with a nice little cheap / loud fan attached. I know I could simply replace the fan... but the PSU I've shown is fanless - and it's Meanwell. It has filtering adjustable voltage and adjustable current, protection against over voltage, over current, over temp and short circuiting.

Where am I scrimping? I've upgraded one of the stepper motors which cost >£150 alone. The Meanwell PSU is industrial and cost over £200, which is why I don't want to simply wire it in and it cooks itself. I could easily get a 24V 25A one for £30 on Amazon.


The output cables are 14 gauge, and a quick google gives me equivalent as 2.5mm2, but I'm not sure how accurate that is.

a. I'm unsure if each output cable would be able to take the 600W (in which case why have 2?)

b. What would the result be of joining the 2x +'s and the 2x -'s as above?

*ep

 

[Spoon]

The output cables are 14 gauge, and a quick google gives me equivalent as 2.5mm2, but I'm not sure how accurate that is.

14 AWG is more like 2.0mm

 

[Bobster]

b. What would the result be of joining the 2x +'s and the 2x -'s as above?

As long as they're the same potential, you'll have to measure with a multi meter. This will probably be the only way to achieve that PSU's maximum output.

 

[Charlie_]

That driver is designed primarily for lighting..
Just get a basic Meanwell psu at the same rating

 

[enpassant]

14 AWG is more like 2.0mm

I've just had another Google and found that, too. Along with another source claiming the same 2.5mm2. Americans and their measurements!

As long as they're the same potential, you'll have to measure with a multi meter. This will probably be the only way to achieve that PSU's maximum output.

The PSU is rated at 600W. My question is relating to the cabling; whether 1 output cable (2x 14AWG) could handle the 600W, or, if not, then I could simply connect the 2 output cables to a busbar and the cables can provide 300W each.

That driver is designed primarily for lighting..
Just get a basic Meanwell psu at the same rating

Yeah, most 3D Printer around have LED drivers as PSU's.

The reason I chose the particular PSU is because it an enclosed, fanless design.

 

[Spoon]

This is where I got mine from.

 

[Bobster]

The PSU is rated at 600W. My question is relating to the cabling; whether 1 output cable (2x 14AWG) could handle the 600W, or, if not, then I could simply connect the 2 output cables to a busbar and the cables can provide 300W each.

This is what I am saying, I wouldn't like to run 25A through a 14awg cable. So I imagine, without downloading a full spec sheet, that the only way to achieve 25amp is but doubling up the conductors and sharing the load.

 

[Spoon]

Wire Sizes - AWG versus Square mm

Comparison of American Wire Gauge against square mm for copper electronic wire

www.controlandinstrumentation.com

 

[enpassant]

This is where I got mine from.
...

Thanks. When I Googled earlier the top answer was 2.5mm2 which is why I wrote it, but other searches showed 2.08 the same as you. If we could just force them to embrace the metric system...!

This is what I am saying, I wouldn't like to run 25A through a 14awg cable. So I imagine, without downloading a full spec sheet, that the only way to achieve 25amp is but doubling up the conductors and sharing the load.

Thanks, that's what I was interested in. So I'll strip the 2 outputs and wire the 2x +'s to 1 busbar and 2x -'s to another like this:



The busbars are rated to 100A so it's the current through the wires that was my main concern.

 

[Charlie_]

“Yeah, most 3D Printer around have LED drivers as PSU's.

The reason I chose the particular PSU is because it an enclosed, fanless design.”
Yes I know, what I’m saying is you can get a basic Meanwell driver without any of the auxiliary controls and with just 1 pair of outgoing terminals for a lot less money..

 

[enpassant]

Yes I know, what I’m saying is you can get a basic Meanwell driver without any of the auxiliary controls and with just 1 pair of outgoing terminals for a lot less money..

Yeah, completely understand... but they're not fanless. The 3D printer cost >6k so I'm not bothered about spending £225 on a PSU for it.

*ep