Power supply for UM1 AND Heated bed

[vdesmedt 0]

Hi,

I have installed an aluminium heated bed bought on ebay and also installed IKEA led inside the UM1. All this is great but I now have three power supplies involved in making the UM1 to work....

UM1 is supposed to be powered with 19V, the heated bed is 24V and the led stripes are 12V.

I wonder if someone could point me to a solution to reduce the amount of PSU to only one with a minimum of electronics.. For example, I wonder is the main board will accept 24V in which case I could power both the UM1 and the heated bed with just one PSU and divise the tension by two with a resistor bridge to power the led.

The PSU for the heated bed in 24V 10A

any suggestion ?

 

[kitwashere 1]

I have an Ikea Led strip in my UM1 as well. There's a spot on the UM shield (1.5.6 at least) marked "19v LED" or something similar. I put a voltage regulator on there and ditched the extra cord.

For the hotbed you'll have to either disconnect the barrel jack on the PCB or solder leads to the legs or something, which are connected to your power supply. I haven't done this, but when I do I'm going to use a power supply dialed down to 19V like the UM is used to. Heated bed might take a little longer to hear up but I'm okay with that

 

[tommyph1208 55]

I have been messing around with the exact same setup myself, close to a working state now.

So far, my solution is:

- 1 industrial 18-24V psu (dialed to 20V), mounted under the UM

- 12V regulator (marked IC1 on your board) replaced with a 12V DC step-down buck from ebay

- LEDs driven from this 12V line as well

- Heatbed connected directly to 20V PSU through Solid State Relay controlled by the UM Boards heatbed port (havent wired this up yet, but sounds like a common approach, exept maybe for using SSR instead of regular Rely)

[anon4321 16]

The SSR is a common approach. See this for some detail discussion. http://umforum.ultimaker.com/index.php?/topic/6014-heated-bed-build-and-a-question-about-the-z-stage/&do=findComment&comment=55219

 

[callum-burns 0]

These relay ways of doing the hotbed switching are horrible! You don't need to buy anything extra only need a small bit of stripboard! Just a case of removing the MOSFET putting it onto the external board with the other psu. No need for a clicky relay. Also gives the option of pwm.

[mr_clark 0]

The solution I ended up using is pretty simple and works well. Before I just used a cheap Chinese chassis psu dialled down to 20v which fed the UM electronics and a relay driven heated bed. The problem with this approach is the bed power is reduced if you are using a 24v designed hot plate or other heated bed element (not really an issue for me as I was using power resistors on a 8mm alu plate). My Chinese PSU died a rather pathetic death so I decided to get something a little better:

http://www.simplypowersupply.com/DIN-Rail-Power-Supply/LP1300D-24M-24Vdc-125A-300W-DIN-Rail-Power-Supply.aspx

A Reign Power SMPS - Still Chinese but a hell of a lot higher quality - I will print a DIN rail and stick it on the back of the UM. It does run a bit warm so may be worth putting a fan on it. I am running at about 285watt peak. It has not cut out or failed yet in a few days worth of printing and seems very robust. Very compact too, I couldn't believe how weighty and compact it felt compared to the cheap chassis PSU I was using before. It can be dialled back to 20v or up past 24v. I keep mine at 24v.

So cables are run from this via 13A mains cable to the UM main board, soldered to the plug location.

Another set of +/- lines from the PSU are taken to this:

http://www.amazon.co.uk/DEOK-Adjustable-Regulator-Experimental-Converter/dp/B00GX3YWNE/ref=sr_1_4?ie=UTF8&qid=1403808293&sr=8-4&keywords=dc+dc+converter

Similar items on Ebay. Pretty good and allows you to dial in your voltage requirement easily. You run the output from this to the spare +/- lines for the fans on the UM driver board. There should be a few spare +/- lines here. Once you have done this you can cut the legs off the 7812 regulator that sits close to that location. This is the linear reg that will crap out at 20+volts without cooling. It's wasteful and the digital regulator is a much more efficient solution, you can draw 2A+ from this new regulator so a plethora of higher power 12v fans could be added if you so wish...

Make sure you have it dialled low before you plug it in, get it set to 12v before you go ahead and install.

Once you have done all of this, you can run a new set of lines from the spare outputs on the PSU to your heated bed, using the driver board mosfet to switch a relay or use an SSR. Works very well and is a more efficient solution.

Good luck. Sorry I don't have a schematic to show you. It does get very busy cable wise and sometimes I wish there was a ribbon solution on the underside of the UM, as with all the cables running around past high power lines, interference is a big problem. I have noticed that with the PSU close to the UM unit, when the heated bed switches on and off there is and immediate impact on the temperature reported from the hot end. I believe this is down to interference as opposed to power deficit due to the fact that there is no drop in voltage across the electronics and current is within spec. I might try winding the cables to see if any flux can be reduced as there is certainly an impact on the very sensitive thermocouple amp.

 

[tommyph1208 55]

The solution I ended up using is pretty simple and works well. Before I just used a cheap Chinese chassis psu dialled down to 20v which fed the UM electronics and a relay driven heated bed. The problem with this approach is the bed power is reduced if you are using a 24v designed hot plate or other heated bed element (not really an issue for me as I was using power resistors on a 8mm alu plate). My Chinese PSU died a rather pathetic death so I decided to get something a little better:

http://www.simplypowersupply.com/DIN-Rail-Power-Supply/LP1300D-24M-24Vdc-125A-300W-DIN-Rail-Power-Supply.aspx

A Reign Power SMPS - Still Chinese but a hell of a lot higher quality - I will print a DIN rail and stick it on the back of the UM. It does run a bit warm so may be worth putting a fan on it. I am running at about 285watt peak. It has not cut out or failed yet in a few days worth of printing and seems very robust. Very compact too, I couldn't believe how weighty and compact it felt compared to the cheap chassis PSU I was using before. It can be dialled back to 20v or up past 24v. I keep mine at 24v.

So cables are run from this via 13A mains cable to the UM main board, soldered to the plug location.

Another set of +/- lines from the PSU are taken to this:

http://www.amazon.co.uk/DEOK-Adjustable-Regulator-Experimental-Converter/dp/B00GX3YWNE/ref=sr_1_4?ie=UTF8&qid=1403808293&sr=8-4&keywords=dc+dc+converter

Similar items on Ebay. Pretty good and allows you to dial in your voltage requirement easily. You run the output from this to the spare +/- lines for the fans on the UM driver board. There should be a few spare +/- lines here. Once you have done this you can cut the legs off the 7812 regulator that sits close to that location. This is the linear reg that will crap out at 20+volts without cooling. It's wasteful and the digital regulator is a much more efficient solution, you can draw 2A+ from this new regulator so a plethora of higher power 12v fans could be added if you so wish...

Make sure you have it dialled low before you plug it in, get it set to 12v before you go ahead and install.

Once you have done all of this, you can run a new set of lines from the spare outputs on the PSU to your heated bed, using the driver board mosfet to switch a relay or use an SSR. Works very well and is a more efficient solution.

Good luck. Sorry I don't have a schematic to show you. It does get very busy cable wise and sometimes I wish there was a ribbon solution on the underside of the UM, as with all the cables running around past high power lines, interference is a big problem. I have noticed that with the PSU close to the UM unit, when the heated bed switches on and off there is and immediate impact on the temperature reported from the hot end. I believe this is down to interference as opposed to power deficit due to the fact that there is no drop in voltage across the electronics and current is within spec. I might try winding the cables to see if any flux can be reduced as there is certainly an impact on the very sensitive thermocouple amp.

 

So everything else on the um board can handle 24V? What about off the board? 19V heater? Steppers?

Your setup is exactly like mine, except I havn't dared turning the PSU past 20V... Also my DC-DC converter dosn't get its 20V IN directly from the PSU but draws them from the board exactly like the 7812 regulator... I just desoldered the 7812 and soldered the DC-DC onto where it sat (IN+ on the 20V side, OUT+ on the 12V side, both IN- and OUT- soldered to the middle...

[zoev89 73]

I have my printer now also working on 1 24V powersupply. I didn't want to run the UM board at 24V since the fans and the hotend would not like the 24V. I bought a small DC DC converter at Markplaats (Frank good service). This converter willl go to 19V so I don't need to change anything on the printer.

Here a photo of the electronics jungle at the bottom including the DC DC converter:

 

 

And this is how I connected the 19V output of the converter to the UM board. I can still use the switch to power on/off the UM.

 

My powersupply takes 6W in idle mode and when the printer is powered in idle it is drawing total of 15W.

 

[tommyph1208 55]

I have my printer now also working on 1 24V powersupply. I didn't want to run the UM board at 24V since the fans and the hotend would not like the 24V. I bought a small DC DC converter at Markplaats (Frank good service). This converter willl go to 19V so I don't need to change anything on the printer.

Here a photo of the electronics jungle at the bottom including the DC DC converter:

 

 

And this is how I connected the 19V output of the converter to the UM board. I can still use the switch to power on/off the UM.

 

 

My powersupply takes 6W in idle mode and when the printer is powered in idle it is drawing total of 15W.

 

So do you run a heated bed directly from the board?

[zoev89 73]

No I do not run the heated bed from the board. I run it from 24V. As Callum mentioned you could remove the mosfet from the board and operate it external (Don't like to put 10A of power through that board). That is the cheapest solution. Or you can make a small board like I have done. This is the schematic:

The parts are not that critical. I just used what I had handy. For the N mosfet it is important to select one with a on resistance of less than 10 mOhm. My mosfet has 10mOhm and it still gets a little warm when heating up. So I just added a little heathsink.

Actually in the setup right now it is not needed to have the optical isolation in there (in my case the PS2561). Since I now run everything from 1 powersupply (The UM board and the heated bed share the same ground).

 

[callum-burns 0]

Finally someone has tried what I was thinking somewhat. Glad it works!

[zoev89 73]

Hi Callum,

No I did not implement your idea. But I do think it is the cheapest way of doing it if you dare to take out the mosfet. In my case the UM mosfet is still there it just lights the diode in my optocoupler.