Power supply - nice one!

[www.ebay.com]

tag on the back says 12v 18A

pdf with pin-out

much nicer than the standard "reprap" power supply. I've seen guys use xbox power supplies and those are < 200 w.

depending on your printer's energy needs (use a kill-o-watt to find out), this should work nicely.

I think my 8" i3 draws a hair over 200 watts when I checked on my kill-a-watt meter last.
I use a "standard" 12v 30amp PSU.

Max power on my prusa i3 is 145W at 12V, but I turned up the voltage to 13.5V to heat up faster. Now it is almost 180W.
I wouldn´t recomment closed/ nonfanned PSUs
-Olaf

I use one. Works Good. We had a few USFF Dells that were being trashed at work, so I grabbed a few PS's.

Hey Olaf, did you have to pull the PS cover off to adjust the voltage? Would love to bump mine up a bit. Is it obvious which pot to adjust?

Quote
elwood127
Hey Olaf, did you have to pull the PS cover off to adjust the voltage? Would love to bump mine up a bit. Is it obvious which pot to adjust?

My PSU is a meanwell 12V/29A type. It has a potmeter right next to the output rail.
But the voltage was not high enough for my earlier purposes ( Charging NiCad 100Ah batteries from my electric car )
So I changed the voltage divider at the optocoupler input to cheat Vout up to 15V.
Only recommended for electronically skilled people...
-Olaf

http://lbmakersociety.org/2012/12/creating-hacking-a-reprap-power-supply-for-ramps/

Ha wow thanks for that link.

Has anyone looked into the XBox On e power supply it has 17.9 amps but I can't find or figure out the wiring on how to turn it on... I'm going to try matching all 3 together to see if that does it just like the image for the Dell PSU.

Have you seen the reprap wiki about power supplys?
[reprap.org]

Ehh.... many of those are just linear voltage regulators instead of Pulse width modified sources.
They are relatively cheap and they can easily be made at home with limited electronics experience.
Afrotechmods on Youtube has number of tutorials that, if you watch, can teach ya how to make a regulated AC-DC power source for cheap.

As far as that goes though, my understanding is that Pulse Width Modified (PWM) power sources, such that come with or are provided by some printer kits, are the most desirable because they prevent both overvoltages and undercurrent situations.

Both faults can cause damage to microprocessors.

A part of me kinda likes the idea of removing as much of the power load from our regulated power supplies as much as possible, but the ubiquity of DC stepper motors makes that idea not entirely feasible.
Through the use of solid state relays you can take most of the draw from a heated bed off of the power supply though, which is helpful.

I had an idea a while ago that might kinda help with hot end power draw, but it'd interfere with printing conductive filaments; If you made a nozzle out of stainless steel, you could use inductive coils to rapidly heat it up and maintain that temperature. You could try and use mains AC and solid state relays, but you'd have to have allot of copper windings to make the alternating magnetic fields strong enough to do the trick. Mains AC isn't usually high enough frequency to be very effective at rapid heating. However, with microprocessor control, you can also use rapidly pulsed DC.

At that point it really comes down to the efficiency of the ceramic heater cartridge vs the inductive heating ability of stainless steel, and I'm not really sure how to make a fair comparison there. There might be some advantage with inductive heating because i've seen setups where the temperature was directly determined by the resistance of the electromagnetic coil, which can act as a thermocouple, but I'm not certain of the accuracy really either.

If it simplified coding, reduced the number of thermistors, and was more efficient it'd be awesome but murphy's law makes that unlikely.