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Meanwell Supplies. Generating - from +
MUFF WIGGLER Forum Index -> Music Tech DIY  
Author Meanwell Supplies. Generating - from +
masterofstuff124
I really would prefer a giant Power Supply.

Currently I use a Stripboard Mfos Wallwart Design. Id need maybe 5 to power my whole rack....

SO then I think this http://www.mouser.com/ProductDetail/Mean-Well/RT-50B/?qs=V9a8iPeg90wc% 2F8AsZNFf%252bg%3D%3D is good
but only .5 a on the - doesnt work and Id still need several.

Then this seems even better http://www.mouser.com/Search/m_ProductDetail.aspx?Mean-Well%2FPD-2512% 2F&qs=V9a8iPeg90zL57YT5CaFMw%3D%3D
1 amp on both +/- but still Id need several.

In comes this beast. http://www.mouser.com/ProductDetail/Mean-Well/LRS-100-12/?qs=vDxCgdWo2 h%2FI2W3ugpCHQg%3D%3D
8.5 amps but only has 12v+

I found this thread on the subject of generating a -12v rail.
https://www.muffwiggler.com/forum/viewtopic.php?t=163315&highlight=

and this useful tidbit-
Yes it will work, but it's more like this:
PSU 1 -> +15V Out as +15V rail
PSU 1 -> 0V out as 0V rail
PSU 2 -> +15V out as 0V rail (connect to 0V rail of PSU1)
PSU 2 -> 0V out as -15V rail.
** CONNECT MAINS EARTH TO 0V RAIL AND THE MAINS EARTH INPUT OF BOTH PSU's. **

Regards,
Stew.

I think on the Meanwell supplies they actually call the outputs V- and V+.

PSU 1 -> V+ Out as +15V rail
PSU 1 -> V- out as 0V rail
PSU 2 -> V+ out as 0V rail (connect to 0V rail of PSU1)
PSU 2 -> V- out as -15V rail.
** CONNECT MAINS EARTH TO 0V RAIL AND THE MAINS EARTH INPUT OF BOTH PSU's. **




So has anyone sucessfully used two meanwells wired in this way? anyhting to be be wary of etc...

8.5 amps on both +/- would be amazing. more then enought to power a giant modular and then some.

maybe there is a better way of doing this. But at about $50 bucks for all that power its looks by far the best solution for the GIANT rigs many of us seem to shoot for.

my entire giant modular is DIY btw/.

any and all help is greatly appreciated.
Armstrb
Wow. I was about to post exactly the same question. My case is built into my built in bookshelves so have tons of space behind the modules (12"), and room to go very big. I am already at 18U x 114HP, and might potentially expand to the bookshelf thats right beside it



Given this, am looking for a large, powerful power supply. Am currently using two Synthrotek 5A Power Supplies with their Noise Distribution Boards, but think I am hitting the limits of what they can do.

This got my investigating and from what I can see the Pitts EP360 is done this way, it has three PSU's from Haitaik, one for each rail. See discussion here:

https://www.muffwiggler.com/forum/viewtopic.php?t=153492&start=200

I haven't been able to find the PSU's anywhere, but Mean Well has equivalents (LRS-75-12 or RS-75-12) that are available from Mouser. These PSU's seem incredible cost effective as are only $20-25 each. So realistically a PSU with 6A or 8A on each rail 12V rail and 3A (LRS-15-5) or 5A (LRS-25-5) on the 5V rail could be constructed for under $100, plus bus boards.

This doesn't seem that complicated but then I worry I am missing something.

So same questions are:

1. Why wouldn't you do this?
2. Has anyone done this? How did it go?
3. Anyone know the difference between the LRS models and RS models?
4. Any issues with putting 6A's or 8A into the Synthrotek distribution boards?
5. Should I daisy chain the distribution boards or connect each individually? If individually, how?
6. Connecting mains power to these PSU's - there needs to be some sort of a splitter. What would you use to do this safely?
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Randy
Usual seems to be the RT-65B, one per bus board or pair of bus boards. I use one per pair.

There's lots of talk of tricky wiring, you can search this forum, but mine are wired as simply as possible and I have had no issues.

Randy
TheSlowGrowth
Connecting power supplies like this is possible, but only if input and output of the supply are electrically isolated (no direct conductive path between input and output). As far as I can tell (see the block digram on page 3 of the datasheet) that is the case for the meanwell LRS-100 supply.

The supply basically keeps its V+ terminal 12 volts above its V- terminal. If V+ is connected to 0V, then V- will be -12V. It's as simple as that.

Before you wire up anything, please take a multimeter and verify that the output is isolated from the input. Put the meter on Ohms mode and measure for continuity between any of the input pins and any of the output pins. If all combinations have no connection you are safe to wire it up the way you described in your post.

BTW, this is a very common thing to do. The typical electronics lab supply works exactly like that so that you can use two supplies to create a positive and a negative rail. A transformer with dual secondary windings also works like that, where each winding acts like a AC voltage source. They are connected at the center tab which serves as 0V.

One thing to note is the ripple (120mV!). I'm using the RT65B which also has 120mV ripple and I don't see any negative effects. But I'm using a lot of digital modules with additional on-board regulation. Some delicate analog modules might actually be disturbed by the ripple. But as far as I know, many people are having no issues with their RT65B's.
Armstrb
Thanks for the tips!
EATyourGUITAR
just get the troggotronic 10A per rail! and its got way better ripple than the meanwell.
yan6
I use three RT-125b wired in parallel to power a large eurorack and 6 serge panels. I built it into a separate enclosure and use 3 pin xlr to connect everything.
masterofstuff124
@theslowgroth

i will use the (beep) continuity test on my mutimeter to verify what you have said before attempting. thank you!
As per the ripple issue I will keep my analog sound source/processing stuff to my linear supply and the rest(digital, control, arduino; ill run off the switching supplies!) so ripple shouldnt be a problem.

@eatyourguitar

the troggotronic brings up some interesting questions. seems like they are simply wiring two seperate (laptop style) power supplies together to generate the +/- that seems incredibly simple. Im suprised that isnt discussed more as a simple Power Solution for Euro.

so for instance is there a way to wire two of something like this for eurorack power https://www.amazon.com/100V-Switching-Power-Supply-Adapter/dp/B01FJAH7 XS/ref=sr_1_16?ie=UTF8&qid=1474312461&sr=8-16&keywords=12v+dc

pre-built AC mains Wiring makes this an Extremely simple(and safer) solution for modular powering assuming it can be this simple! seems like this is how troggotronic does their power solutions.
masterofstuff124
http://electro-music.com/forum/viewtopic.php?highlight=power+supply&t= 50746


bought two of these to test.

https://www.amazon.com/gp/product/B01BDFQ7NO/ref=oh_aui_detailpage_o00 _s00?ie=UTF8&psc=1
lohacker
Necroing this thread for help on this same subject, I've found this pic in the meanwell manual


but I don't understand clearly for my noob skills.. (hides)

How I should wire 2x RS-75 12v psu to have both negative and positive voltages and proper ground?

Thanks in advance thumbs up
lohacker
bump..
any help for a wiggler without space left in his cases? help
Synthiq
First an observation: if you need to ask this, maybe you are not ready to do this kind of work. Mains voltages can be lethal so there is no room for mistakes here, so don't do this unless you are absolutely sure you know what you are doing.

Your picture pretty much describes how to connect your modules. On the high voltage side you have 3 inputs marked with "L", "N" and a ground symbol. connect the 2 modules in parallel, so L to L, N to N and ground to ground. Use cables that can handle the voltages and should be marked with 600V. Then make sure they are connected correctly to the incoming power cable. The L, N and ground wires in the cable have different colors but varies between countries so you have to check the standard for your country.

On the low voltage side, you connect the +V output from the first module to the +12V output and the -V output to 0V. The +V of the second module is connected to 0V and the -V output to -12V.

You should also connect the ground pin on the high voltage side to the 0V output.
Swyndger
lohacker wrote:
[...] I've found this pic in the meanwell manual [...]


Wher did you find this scematic?
I was searching for an information which meanwell psu/smps can be wired to a bipolar one.
lohacker
Synthiq wrote:
First an observation: if you need to ask this, maybe you are not ready to do this kind of work. Mains voltages can be lethal so there is no room for mistakes here, so don't do this unless you are absolutely sure you know what you are doing.

Your picture pretty much describes how to connect your modules. On the high voltage side you have 3 inputs marked with "L", "N" and a ground symbol. connect the 2 modules in parallel, so L to L, N to N and ground to ground. Use cables that can handle the voltages and should be marked with 600V. Then make sure they are connected correctly to the incoming power cable. The L, N and ground wires in the cable have different colors but varies between countries so you have to check the standard for your country.

On the low voltage side, you connect the +V output from the first module to the +12V output and the -V output to 0V. The +V of the second module is connected to 0V and the -V output to -12V.

You should also connect the ground pin on the high voltage side to the 0V output.


Synthiq
Thanks for your input, I know can be risky to work with mains voltages if you don't really know what you're doing, but since here where I live I can't find anyone that can help me I have to figure it out by myself and I'm reading anything that can teach me about this.
Until now I've just used their RT line psu supplying direct +12/-12/+5V, so it was easy enough to make connections, now I'd need more power for my next case so I was looking for this dual configuration.

Now, looking at the actual RS-75 image and trying to follow your instructions I’m not sure how to wire it up correctly:

I see +V1, +V2 and 2 com ports (there’s a difference in these 2 com?)

Another thing in the picture attached previously that confuses me is that RL symbols between +V/-V and COM, do I need to place a resistor there?


Swyndger
That scheme is taken from the manual here:
https://www.adminstrumentengineering.com.au/files/mean-well-user-techn ical-manual.pdf
Synthiq
That's weird. When I looked at the RS-75 spec at Jameco it only have 5 terminals so I assumed it was identical to the LRS-50s I have.



So now I understand your question better. It looks like the module actually have 2 outputs, V1 and V2, possibly with a common negative connection. Can you measure if the 2 COM terminals are shorted or isolated with a DMM?

Maybe it isn't a RS-75 but a NED-75?



If this is the case, the 12V output V2 can only supply 3A or 36W so this is probably not what you want?
Synthiq
lohacker wrote:
Another thing in the picture attached previously that confuses me is that RL symbols between +V/-V and COM, do I need to place a resistor there?


No, RL just mean Rload, which in this case is your modular.
lohacker
Synthiq wrote:

Maybe it isn't a RS-75 but a NED-75?



If this is the case, the 12V output V2 can only supply 3A or 36W so this is probably not what you want?


Actually I haven't ordered it yet, since I'd like to be sure how to wire it up, but looking at your pic attached the connection is more straightforward.
Here's the link where I'm getting it, maybe could be a wrong pic on their site, and can't find a ned-75 model there, I'll try to contact them and sort it out. Thanks again! thumbs up
Synthiq
Most likely they just used the wrong picture. The spec says 12V @ 6A so this is a single output model.
lohacker
Don't know.. the more I search the less it's clear hmmm.....
I see there are several RS-75-12.. (RSP-75, LRS-75, SNT RS-75), maybe I should point to another model providing enough juice, suggestions? Anyone knows the one 12v used in PGH structure 420 cases?
Synthiq
The RSP-75 seems to be a RS-75 with power factor correction and a higher price and somewhat larger size. The LRS-75 appears to be an upgrade of the RS-75 with higher efficiency, smaller physical size and a lower prize. I'm not sure what the SNT RS-75 is, but of these I would go with the LRS-75 since I have experience with the similar LRS-50.
lohacker
Synthiq wrote:
The RSP-75 seems to be a RS-75 with power factor correction and a higher price and somewhat larger size. The LRS-75 appears to be an upgrade of the RS-75 with higher efficiency, smaller physical size and a lower prize. I'm not sure what the SNT RS-75 is, but of these I would go with the LRS-75 since I have experience with the similar LRS-50.


Thanks for your invaluable support Synthiq I owe you a virtual beer Guinness ftw!
I'll go with 2x LRS-75-12 then!
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