Is this power supply fake?

[zapta]

The Seasonic 620W arrived today. It has a slick black case with connectors only. I had to short that switch signal to ground to get it started. The fan is  very quite and I had no problem to get 200W out of a 12V connector (my electronic load goes up to 200W).  Open voltage was 12.1 volt and at 200W it went down to 11.V (measured directly on the connector, a little bit less at the electronic load).

The only down side is that these ATX power supplies have very specific mounting holes and are not general bracket friendly.

Thanks everybody for the information.  The 3D printer kit will arrive on Tuesday.

[LabSpokane]

Open voltage was 12.1 volt and at 200W it went down to 11.V (measured directly on the connector, a little bit less at the electronic load).

You do realize that the load regulation of that supply is absolute crap, right?  Even a bargain basement DIN rail supply is rated at 2% - and will meet the spec.

[ajb]

If you examine the cables that came with your power supply you might be able to identify some sense wires for the 12V rails.  Connecting them up ought to give you better regulation.

[zapta]

If you examine the cables that came with your power supply you might be able to identify some sense wires for the 12V rails.  Connecting them up ought to give you better regulation.

I will give it a try. I sued my own 4x2 mini fit cable with parallel beefy wires and measured the voltage directly on the output connector of the PSU. Do you expect the stock wires to have voltage sense? If not, why do you expect them to give better results?

[Rasz]

Do you expect the stock wires to have voltage sense? If not, why do you expect them to give better results?

yes, 12v line has separate sense wire on ATX connector

[zapta]

Do you expect the stock wires to have voltage sense? If not, why do you expect them to give better results?

yes, 12v line has separate sense wire on ATX connector

Ok, that's make sense, though I would expect that the voltage sense will not just be open but also connected with internal resistors to the power out points of the unit which is the point where I measured the voltage.

[zapta]

I just measured resistance between the pins of one of the 12V output connector. All four (+) pins have perfect short and so all the four (-) pins.  Doesn't look like it has voltage sensing.

[wraper]

Seems that what I said is happening now. Try to put some load (at least 0.5A, more is better) on the 5V rail. Pretty sure that load regulation on 12V rail will return to normal.

[zapta]

Seems that what I said is happening now. Try to put some load (at least 0.5A, more is better) on the 5V rail. Pretty sure that load regulation on 12V rail will return to normal.

Thanks. I will give it a try and will report here.

[Psi]

ATX power supplies really can't be beat for 12v, and if you buy a modular one you won't have to worry about a massive swathe of cables you need to bundle up out of the way. High current, good protection, and most of the time cheaper than a purpose built supply. I shorted one recently and fully expected it to explode the cables in my face, turns out it has polyfuses though, very neat.

heh, i've seen what happens when they don't have a polyfuse, its not pretty.
PSU is usually fine, but the cables all turn into horrible thick smoke for a few seconds until you get a direct short as wires melt into each other and the chip shuts down from overcurrent.

[wraper]

Just buy a good quality ATX PSU.

ATX power supplies really can't be beat for 12v, and if you buy a modular one you won't have to worry about a massive swathe of cables you need to bundle up out of the way. High current, good protection, and most of the time cheaper than a purpose built supply. I shorted one recently and fully expected it to explode the cables in my face, turns out it has polyfuses though, very neat.

Where did you see polyfuses in ATX psu? There is overcurrent protection if it is not complete junk but no polyfuses. Just imagine a size of the PTC holdling a few dozens of amperes. Moreover they are so slow that everything will fail before it trips.

[zapta]

Seems that what I said is happening now. Try to put some load (at least 0.5A, more is better) on the 5V rail. Pretty sure that load regulation on 12V rail will return to normal.

Yes, you are right, I connected a  7.5ohm resistor to the 5V and the 12V rail is now at 11.875V on the load at 16A. Much better.

Not sure if I like this power supply. I may get a real one.

[a210210200]

Seasonic ATX power supplies are generally good quality stuff,

Is this the power supply you have?
http://www.hardocp.com/article/2010/05/18/seasonic_m12ii620_power_supply_review/2

It is noted for not being the best in voltage regulation and is an older design.

Most good quality ATX power supplies have short circuit protection which isn't just a polyfuse as it acts basically instantly and is usually digitally controlled circuit that cuts off the entire supply if it detects a short circuit or other trip event (If you have thousands of dollars of equipment plugged into a power supply you don't want a not fully seated card or DIMM melt the motherboard sockets). They also have low noise optimized fan curves as some power supplies don't even run the fan if your not drawing power and smoothly ramp up with load/temperature unlike some industrial psus which either have a on/off thermostatic or really loud fan.

[HackedFridgeMagnet]

Pass on the Meanwell. You can thank me later.

Don't post nonsense like that. How can he thank you later?

Back up what you say with some reasoning, reference or experience, or state that it is just a random opinion or even easier don't say anything at all.

[zapta]

Seasonic ATX power supplies are generally good quality stuff,

Is this the power supply you have?
http://www.hardocp.com/article/2010/05/18/seasonic_m12ii620_power_supply_review/2

It is noted for not being the best in voltage regulation and is an older design.

Most good quality ATX power supplies have short circuit protection which isn't just a polyfuse as it acts basically instantly and is usually digitally controlled circuit that cuts off the entire supply if it detects a short circuit or other trip event (If you have thousands of dollars of equipment plugged into a power supply you don't want a not fully seated card or DIMM melt the motherboard sockets). They also have low noise optimized fan curves as some power supplies don't even run the fan if your not drawing power and smoothly ramp up with load/temperature unlike some industrial psus which either have a on/off thermostatic or really loud fan.

I think I have this one  (their product ids are very confusing, I think they try to appeal to games or something)

http://www.seasonicusa.com/M12II-Bronze.htm

It's quite, has integrated on/off switch and fully modular (that is, not wires coming out of the case, just connectors). The down side is that it requires a 5V power resistor to have decent regulation on the 12V. Also, has a ATX PSU, it has limited mounting options.

[zapta]

Pass on the Meanwell. You can thank me later.

Don't post nonsense like that. How can he thank you later?

He meant well.

;-)

[LabSpokane]

Pass on the Meanwell. You can thank me later.

Don't post nonsense like that. How can he thank you later?

Back up what you say with some reasoning, reference or experience, or state that it is just a random opinion or even easier don't say anything at all.

Is a 100% failure rate enough for you?  I've had to deal with them commercially and replaced EVERY SINGLE ONE at great expense. They may "mean well", but they make shit power supplies.  I'd flat out fire anyone that used a Meanwell in our equipment. It just demonstrates a complete lack of judgement.

Phoenix, Sola, Automation Direct, etc. all make a nice power supply that will meet specs and last.

[a210210200]

Anybody knows reputable manufacturer of module ATX PSU's (with connector only outputs)?  I prefer to have a safe product with UL and such.

Edit: I just leaned that modular ATX PSU with output connectors only are called 'fully modular'.

SFX and TFX supplies are also just different physical form factors and will carry the safety ratings as ATX supplies will. (They are meant for smaller form factor cases).

TFX,

http://www.newegg.ca/Product/Product.aspx?Item=N82E16817151115 (Two rails 12V 200W each, fully modular, review: http://www.hardocp.com/article/2012/04/04/seasonic_ss350tgm_power_supply_review/  )

SFX,

http://www.silverstonetek.com/product_power.php?tno=7&area=en , (Single rail multiple versions, a little off on the regulation side, very tiny, fully modular available) http://www.hardocp.com/article/2014/08/26/silverstone_sfx_sx600g_600w_power_supply_review/9

Since I just like top end stuff I use seasonic atx supplies like this one (They are pricy stuff at that point but fanless at low use and very tight regulation/noise),
http://www.hardocp.com/article/2013/02/04/seasonic_platinum660_660w_power_supply_review/4

(Technically if you put the 3d printer close enough (right beside) to your computer tower you could run it off the 12V PCI-E cabling which are meant to run GPU's drawing hundreds of watts of power at 12V)

Seasonic, Antec, Corsair, ... are all good mfgs. It actually depends sometimes as most companies use a third party to do the design/mfg. Seasonic just happens to be both an OEM and direct sales.

Computer review sites like hardocp have a pretty good computer power supply test suite and cover a lot of supplies. (You want sites that give you internal shots, ripple, efficiency, regulation test results)

Tom's hardware/anandtech also do reviews on computer power supplies as well.
http://www.tomshardware.com/articles/?tag=power-supplies&articleType=review

[TheRevva]

You want a PSU for a Reprap type project...
I'd SERIOUSLY consider looking on 'fleabay' for NOS (New / Old Stock) HP server PSUs.
They're built to last quite a while and, depending on the model, can give you all the current you'd ever want for your heatbed / hotend / stepper motors.

On my Reprap, I ended up using TWO HP PSUs (HP part number 382175-501) that I 'acquired' for free.  (One would have been enough since the 12V rail is rated at 60A max)
SOME of the HP server supplies don't have all the output rails of a traditional ATX supply (and some of them intentionally set their output a couple hundred millivolts high to cater for cable resistance losses)
Here's the first 'fleabay hit' in my search for HP server PSU:
http://www.ebay.com/itm/HP-DL360-DL385-G5-Server-700W-Power-Supply-Unit-411076-001-412211-001-393527-001-/231179762487?pt=US_Server_Power_Supplies&hash=item35d3633b37
US$15.29 will buy you this 700W PSU.
It doesn't have a 5V output at all (the standby output rail is 3V3 @ 3.5A.  Might be useful though if you're using an ARM instead of an Arduino Mega etc.)
The main +12V rail is actually 12.15V @ 56A
It also has a weird 10.5V @ 1.5A standby output too?

Nevertheless, I'd GLADLY run a Reprap from it (inclusive of a decent Mk1a heatbed for ABS printing).

Your post has reminded me...  I must 'make some progress' on my CNC machine.  (Nema23 steppers, PSUs, endmills etc all here, just need to nut out the rest of the physical design)

[HackedFridgeMagnet]

Pass on the Meanwell. You can thank me later.

Don't post nonsense like that. How can he thank you later?

Back up what you say with some reasoning, reference or experience, or state that it is just a random opinion or even easier don't say anything at all.

Is a 100% failure rate enough for you?  I've had to deal with them commercially and replaced EVERY SINGLE ONE at great expense. They may "mean well", but they make shit power supplies.  I'd flat out fire anyone that used a Meanwell in our equipment. It just demonstrates a complete lack of judgement.

Phoenix, Sola, Automation Direct, etc. all make a nice power supply that will meet specs and last.

Sry about the post LabSpokane, I must've been having a bad hair day.

I've only ever had 2 of them, they're working fine. Maybe I don't run them hard enough.
They seem good value for money to me.
How did those supplies fail? How many failed? Did you get warranty?

[LabSpokane]

Pass on the Meanwell. You can thank me later.

Don't post nonsense like that. How can he thank you later?

Back up what you say with some reasoning, reference or experience, or state that it is just a random opinion or even easier don't say anything at all.

Is a 100% failure rate enough for you?  I've had to deal with them commercially and replaced EVERY SINGLE ONE at great expense. They may "mean well", but they make shit power supplies.  I'd flat out fire anyone that used a Meanwell in our equipment. It just demonstrates a complete lack of judgement.

Phoenix, Sola, Automation Direct, etc. all make a nice power supply that will meet specs and last.

Sry about the post LabSpokane, I must've been having a bad hair day.

I've only ever had 2 of them, they're working fine. Maybe I don't run them hard enough.
They seem good value for money to me.
How did those supplies fail? How many failed? Did you get warranty?

No worries. Peace.

I don't have my lab notebook so I don't remember the exact failure mode. We replaced 50-75 of them in the field at our expense. Of course, they were all located on secure, government facilities and the tech had to be escorted, so it was slow, excruciating, and expensive. That was in addition to the internal expenses of changing BOMS, drawings, creating replacement wiring harnesses, fighting management, and profusely apologizing to a great customer for our negligence.

The Meanwells bench tested ok when new at room temp with light loads. Unfortunately, the engineer who spec'ed them out never bothered to put them on a e-load and stuff them into an environmental chamber.  I honestly believe that Meanwell simply copied the data on competitors' spec sheets based on what I saw. 

I didn't pursue warranty because I wouldn't field the replacement units.

MWs are probably fine for light duty in office environments for non-critical work. For commercial work or for times when your time is worth money, there are just so many better choices. Yes, those choices cost more, but they will also last and last. And like was already noted, I think you're far better off buying a good, industrial power supply used off ebay than a new crap one.

[a210210200]

You want a PSU for a Reprap type project...
I'd SERIOUSLY consider looking on 'fleabay' for NOS (New / Old Stock) HP server PSUs.
They're built to last quite a while and, depending on the model, can give you all the current you'd ever want for your heatbed / hotend / stepper motors.

On my Reprap, I ended up using TWO HP PSUs (HP part number 382175-501) that I 'acquired' for free.  (One would have been enough since the 12V rail is rated at 60A max)
SOME of the HP server supplies don't have all the output rails of a traditional ATX supply (and some of them intentionally set their output a couple hundred millivolts high to cater for cable resistance losses)
Here's the first 'fleabay hit' in my search for HP server PSU:
http://www.ebay.com/itm/HP-DL360-DL385-G5-Server-700W-Power-Supply-Unit-411076-001-412211-001-393527-001-/231179762487?pt=US_Server_Power_Supplies&hash=item35d3633b37
US$15.29 will buy you this 700W PSU.
It doesn't have a 5V output at all (the standby output rail is 3V3 @ 3.5A.  Might be useful though if you're using an ARM instead of an Arduino Mega etc.)
The main +12V rail is actually 12.15V @ 56A
It also has a weird 10.5V @ 1.5A standby output too?

Nevertheless, I'd GLADLY run a Reprap from it (inclusive of a decent Mk1a heatbed for ABS printing).

Your post has reminded me...  I must 'make some progress' on my CNC machine.  (Nema23 steppers, PSUs, endmills etc all here, just need to nut out the rest of the physical design)

As long as you don't mind the noise getting a used server power supply may be a good idea they are built much more robustly and if you want you can get N+1 redundant ones. Just most use small ultra-high rpm fans so can make a lot of noise if doesn't have a load/temp ramp.

[TheRevva]

You want a PSU for a Reprap type project...
I'd SERIOUSLY consider looking on 'fleabay' for NOS (New / Old Stock) HP server PSUs.
They're built to last quite a while and, depending on the model, can give you all the current you'd ever want for your heatbed / hotend / stepper motors.

On my Reprap, I ended up using TWO HP PSUs (HP part number 382175-501) that I 'acquired' for free.  (One would have been enough since the 12V rail is rated at 60A max)
SOME of the HP server supplies don't have all the output rails of a traditional ATX supply (and some of them intentionally set their output a couple hundred millivolts high to cater for cable resistance losses)
Here's the first 'fleabay hit' in my search for HP server PSU:
http://www.ebay.com/itm/HP-DL360-DL385-G5-Server-700W-Power-Supply-Unit-411076-001-412211-001-393527-001-/231179762487?pt=US_Server_Power_Supplies&hash=item35d3633b37
US$15.29 will buy you this 700W PSU.
It doesn't have a 5V output at all (the standby output rail is 3V3 @ 3.5A.  Might be useful though if you're using an ARM instead of an Arduino Mega etc.)
The main +12V rail is actually 12.15V @ 56A
It also has a weird 10.5V @ 1.5A standby output too?

Nevertheless, I'd GLADLY run a Reprap from it (inclusive of a decent Mk1a heatbed for ABS printing).

Your post has reminded me...  I must 'make some progress' on my CNC machine.  (Nema23 steppers, PSUs, endmills etc all here, just need to nut out the rest of the physical design)

As long as you don't mind the noise getting a used server power supply may be a good idea they are built much more robustly and if you want you can get N+1 redundant ones. Just most use small ultra-high rpm fans so can make a lot of noise if doesn't have a load/temp ramp.

Granted, MOST server PSUs are, as A21... has mentioned, somewhat louder than your typical ATX desktop CPU. However...
1: We're talking about a Reprap type project here...  I cannot even HEAR mine over the noise of the 5 * Nema17 stepper motors.
2: They're generally FAR more 'reliable' than a typical ATX PSU
The latter point is quite important.  Your heatbed ALONE will be sucking a BIG chunk of 'juice'.  I dare you to take apart almost ANY ATX PSU and then do a quick datahsheet lookup on the dual schottkey diode used for the +12V rail.  You truly have to wonder how the designers kept a straight face in stating that the rail is 'rated' for 500+ Watts when they're using a dual Schottkey rated at a measly 10-20 Amperes.

If you DO go with an ATX, I'd recommend investigating that rectifier (and 'upgrading' it if applicable).  I'd also SERIOUSLY inspect the LOW-ESR output caps at the same time.  (Take a look at some of the 'horror stories' on the badcaps.net forum).  After that, I'd suggest you think seriously about the 'load' that your reprap is placing on the PSU.  The stepper coils are all nice reactive inductors.  Not boring old resistive loads.  Thankfully, the inductance of your heatbed is VERY small (by design).  However, your hotend heater will, quite likely, be another fairly high current inductive load.

P.S.
It's probably a good idea to grab a few spare Power MOSFETS while you're at it.  I let out the smoke from the pair on my RAMPS board several times before I got it right.  (They're no longer mounted on the RAMPS)
Another 'pointer'...  Keep imagining that you're running a 2.4kW heater through every wire you install.  (You're not of course, but you'll thank me in the end)

[zapta]

The Seasonic died today when I accidentally shorted the +12V output. First it stopped working (didn't turn on) and after 10-15 minutes I could turn it on again but it is very noisy and barely gives 1 amp.

Aren't these power supplies suppose to be protected against an output short?

I plan to stop at the store tomorrow and get the ATX power supply recommended by MakerFram. It's not modular but I can rip all the fixed wires I don't need.

http://www.staples.com/Antec-VP-450W-Power-Supply/product_928656

[TheRevva]

The Seasonic died today when I accidentally shorted the +12V output. First it stopped working (didn't turn on) and after 10-15 minutes I could turn it on again but it is very noisy and barely gives 1 amp.

Aren't these power supplies suppose to be protected against an output short?

I plan to stop at the store tomorrow and get the ATX power supply recommended by MakerFram. It's not modular but I can rip all the fixed wires I don't need.

http://www.staples.com/Antec-VP-450W-Power-Supply/product_928656

I'd be mildly apprehensive about running a Reprap on a 450W ATX PSU...
Sure, it probably is 'within spec' (just), but it'd be like running your car engine on the RPM Redline 24/7.
I assume you have a heatbed (for printing ABS).  Generally, these only suck about 10A from the +12V rail.  (Circa 120W)
Your hotend heater can vary HUGELY depending on the design.  I've seen some nichrome wire based heaters trying to pull 20A (240W), but mine only eats 4A (48W).  Let's take a stab at 40W since this is more common.
The only other current drain (of any significance) is all your stepper motors. Generally 4 or 5 Nema 17 steppers.  (X axis, Y axis, 1 or 2 Z axis and a filament feeder)
Assuming you use a decent stepper driver (such as the Allegro A4988) you can easily see 2A peak currents on each winding (albeit for VERY short durations since it tries to keep the AVERAGE current at the set-point)...  However, worst case that still gives 2A * 5 motors * 2 coils per motor = 20A PEAK (240W)

Adding it all up -> Heatbed + Hotend + Motors = 120W + 40W + 240W = 400W peak drain even if you use a whimpy hot end heater like mine!
If I was FORCED to use a 450W PSU, I'd use a PAIR of them.  One for the heatbed and the other for the hotend + steppers.  This is exactly WHY RAMPS boards have separate inputs from PSU(s).  In my case, my RAMPS board only 'sees' the stepper motors since I've mounted the power FETs offboard (after letting out their smoke a few too many times)

What controller design are you using?