Swapping the stock PS for a Mean Well SE-450-24  

RE: Swapping the stock PS for a Mean Well SE-450-24

It's a remote sense connector.

The PSU can use it to sense the voltage at the remote end of the DC cable and adjust the output to achieve nominal voltage there.That is needed since the SE-450 line of MeanWell PSUs goes all the way down to 3.3V at 75A. At that current, the voltage drop on the cable is significant and can easily be 10% of the nominal 3.3V voltage. So the PSU will output a higher voltage and monitor that 3.3V reaches the device it is powering. It's not particularly useful at 24V/19A if thick (>= 2.5 mm²) enough cables are used. First, the voltage drop will be much smaller at 19A, second, it'll be a smaller percentage of 24V.

It doesn't serve the purpose of turning the PSU on or off and so it's not useful for purposes of reset.

Why do you plan to swap the PSU?

RE: Swapping the stock PS for a Mean Well SE-450-24

Why not go with the meanwell LRS350-24 that seems a popular substitute? There seem to be plenty of options on thingiverse for adapting the LRS350's slimmer case to mount in place of the stock PSU. I currently have an LRS350-24 sitting in my spare parts pile for if/when the stock PSU ever gives me trouble.

Also note that IMO these meanwells have a rather noisy fan on them. I ended up using one to supply power to LED lighting on my workbench and the fan was loud enough to be heard across the room, noticeably louder than the printer itself, and I ended fabricating a custom cover for a large noctua fan.

Scott

RE: Swapping the stock PS for a Mean Well SE-450-24

Posted by: scott.b47

Why not go with the meanwell LRS350-24 that seems a popular substitute? There seem to be plenty of options on thingiverse for adapting the LRS350's slimmer case to mount in place of the stock PSU. I currently have an LRS350-24 sitting in my spare parts pile for if/when the stock PSU ever gives me trouble.

Also note that IMO these meanwells have a rather noisy fan on them. I ended up using one to supply power to LED lighting on my workbench and the fan was loud enough to be heard across the room, noticeably louder than the printer itself, and I ended fabricating a custom cover for a large noctua fan.

Scott

If you go with the LRS350, there are several options for mounting 80mm, low noise fans, on thingiverse. 

I opted for an Arctic F8 Silent.  You have to move the connector from the stock fan, over to the new fan, but that's relatively simple.  It makes all the difference in the world. 

*edit* Sorry for the tiny picture.  Apparently I can't show it at native resolution....

RE: Swapping the stock PS for a Mean Well SE-450-24

I also imagine that PR will release the MK3S Delta PSU soon-ish. Having a silent PSU is nice 🙂

RE: Swapping the stock PS for a Mean Well SE-450-24

Posted by: BMac

I also imagine that PR will release the MK3S Delta PSU soon-ish. Having a silent PSU is nice 🙂

Even the PRPZ-24-240 can be made silent with some silicone sealant. 

RE: Swapping the stock PS for a Mean Well SE-450-24

Posted by: Vojtěch

It's a remote sense connector.

The PSU can use it to sense the voltage at the remote end of the DC cable and adjust the output to achieve nominal voltage there.That is needed since the SE-450 line of MeanWell PSUs goes all the way down to 3.3V at 75A. At that current, the voltage drop on the cable is significant and can easily be 10% of the nominal 3.3V voltage. So the PSU will output a higher voltage and monitor that 3.3V reaches the device it is powering. It's not particularly useful at 24V/19A if thick (>= 2.5 mm²) enough cables are used. First, the voltage drop will be much smaller at 19A, second, it'll be a smaller percentage of 24V.

It doesn't serve the purpose of turning the PSU on or off and so it's not useful for purposes of reset.

Why do you plan to swap the PSU?

I am building a Full Bear, initially as an upgrade to my MK3S but I have swapped out so many parts that I finally just decided to purchase the remainder of components and build a second MK3S Full Bear.  I will be incorporating LEDs, cameras, Pi 3B+ and possibly other things down the road.  I didn't want to use the std PS for this because I don't want to load it up and run it too hot.  I generally like to oversize my PSs to the next size up, and the 450-watt unit seemed like the right choice, whereas the 350-watt stock was just too close to where I need to be without future needs.

Thanks for the feedback on the four pin remote sense connector.  If I wanted to use this how would I do that, can you point me to any documentation?  Also is there an easy way to integrate a remote reset switch like what comes on the std PS?

RE: Swapping the stock PS for a Mean Well SE-450-24

I forgot to add that there will also be touch screen for the Pi running either a Repetier server or Octoprint with TouchUI; I haven't decided which one yet, but I am leaning towards Repetier.

RE: Swapping the stock PS for a Mean Well SE-450-24

Posted by: michael.p77

I generally like to oversize my PSs to the next size up, and the 450-watt unit seemed like the right choice, whereas the 350-watt stock was just too close to where I need to be without future needs.

I'm surprised. The PRPZ-24-240 is a 10A power supply and it's able to run the printer in its default configuration (Maximum power use of the Mk3 with default firmware running on 24V supply is about 9.8A.). Even with an additional RPi, camera, screen, fans, there is no way you'd get close to consuming the 14.6A that the LRS-350-24 provides. Neither to the 18.8A from the SE-450-24. Plus all the PSUs can handle short term overload up to at least 10% without any issue.

Thanks for the feedback on the four pin remote sense connector.  If I wanted to use this how would I do that, can you point me to any documentation? 

To do that, you'd connect the sense connector to the Einsy power input with an additional set of wires. These can be thin. However, since the Einsy has two power inputs, you'd need to additionally connect them together with thick wires locally rather than running a separate pair from the PSU. It'd look like this:

• Einsy Power ↔ Einsy Bed: thick wires
• Einsy Bed ↔ Einsy Power: thick wires
• Einsy Power ↔ PSU sense:  thin wires

Now the thick wires need to be able to carry all the current, so they need to be sized for 18.8A with some headroom. Check the standard engineering tables for that. The thin ones are sense only and can be as thin as any of the signal wires on the Mk3.

Also is there an easy way to integrate a remote reset switch like what comes on the std PS?

There is no remote reset switch on the PRPZ PSU. The reset wire from the reset button on the display is wired to the CPU and not the PSU.  If you're asking about the power panic functionality, then that, too, is independent of the PSU and is implemented on a custom Prusa board inside the PSU's plastic enclosure. The power switch, too, is a part of that custom Prusa board.

RE: Swapping the stock PS for a Mean Well SE-450-24

That second bullet should say

• Einsy Bed ↔ PSU Power: thick wires

RE: Swapping the stock PS for a Mean Well SE-450-24

Posted by: Vojtěch If you're asking about the power panic functionality, then that, too, is independent of the PSU and is implemented on a custom Prusa board inside the PSU's plastic enclosure. The power switch, too, is a part of that custom Prusa board.

Hi vojtech-p6,

I have the terminology wrong as it is the power panic function that I am looking to keep.  If I were to reverse engineer that board and wiring, would it be as simple as duplicating it to the Mean Well?  If not as simple as that or if unadvisable due to safety concerns then is there a safe way to keep that functionality?  While I am not an electrical engineer, I can follow instructions and assemble electronics with above average skills, although admittedly I am still what you would call a hack.

Thanks for the other info.  BTW I looked at the Mean Well 350 but decided against it due to my "only wanting to do this once" philosophy.  As you keep trying to pull me back in, which I appreciate the advice, I feel that I have legitimate reasons for my choice. On the full bear, I won't be running the stock extruder, and I am currently looking to print some filaments with some relatively high temp requirements, up to the Thermax Peek filament.  If possible, this will require a new heat bed, thermister and temp sensor, and it will run in a custom enclosure, with remote power and electronics.  All of which will draw more current than I have listed above.  I also have a second PS for some of the enclosure needs.

RE: Swapping the stock PS for a Mean Well SE-450-24

Posted by: michael.p77

I have the terminology wrong as it is the power panic function that I am looking to keep.  If I were to reverse engineer that board and wiring, would it be as simple as duplicating it to the Mean Well?  If not as simple as that or if unadvisable due to safety concerns then is there a safe way to keep that functionality?  While I am not an electrical engineer, I can follow instructions and assemble electronics with above average skills, although admittedly I am still what you would call a hack.

The Power Panic board is attached directly to the power socket. It's where the high voltage (N, L, PE) wires go to the PSU. The remaining connections are +24V from the PSU and Panic and GND wires to the Einsy. Pretty darn simple. It'll work with any 24V PSU. It's not inside the PSU, it's inside the 3D printed shroud that covers the PSU terminals. All you'll need to do is to customize the shroud to fit your new PSU mechanically.

Thanks for the other info.  BTW I looked at the Mean Well 350 but decided against it due to my "only wanting to do this once" philosophy.  As you keep trying to pull me back in, which I appreciate the advice, I feel that I have legitimate reasons for my choice. On the full bear, I won't be running the stock extruder, and I am currently looking to print some filaments with some relatively high temp requirements, up to the Thermax Peek filament.  If possible, this will require a new heat bed, thermister and temp sensor, and it will run in a custom enclosure, with remote power and electronics.  All of which will draw more current than I have listed above.  I also have a second PS for some of the enclosure needs.

The SE-450-24 will work just fine and you'll always have power to spare.