Moving to 24v

Anybody here who replaced the psu of the ormerod2 with a 24v?
Any change required despite the duet/duet4x rated for 24v?
Any suggestion which psu ?

Thanks.

Issues I see with using 24V to power the O2 are:

1. The hot end heater cartridge, hot end fan fan, and heated bed are designed for 12V. So you need to procure alternative ones that will be OK on 24V.

2. The O2 uses a linear regulator to produce the 5V supply. The power dissipation in this will increase substantially, You can either add additional heatsinking, or you can disconnect it and enable the switching regulator on the Duet (as on the O1) instead.

You can find 24V regulated power supplies on eBay, which are similar in construction (and probably origin) to the standard O2 power supply. For example, [www.ebay.co.uk] lists a 15A/360W one.

Your O2 power supply probably has a voltage adjustment potentiometer that can be turned up to about 14V. If you are just looking for a little more heated bed power, that may suffice.

---

Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

You read my mind!
I just want to speed up the bed a bit! Maybe 14v might be enough and will not force to change other parts.

Was the bed not already ready for 24v?

btw reading, just now, you blog. Did you calculate what is needed for four noozle as wattage?

Edited 2 time(s). Last edit at 01/07/2015 05:13PM by Fpex.

Quote
Fpex
I just want to speed up the bed a bit! Maybe 14v might be enough and will not force to change other parts.

Power goes up as the square of the voltage, so using 14V instead of 12V will increase the power by 36%. Be careful though, a number of users have had problems with the connections to the O2 heated bed. The O1 ribbon cable connector seems much more reliable - provided you don't plug it into the Duet offset by a couple of pins.

Quote
Fpex
Was the bed not already ready for 24v?

I doubt it - 24V would run it at 4x normal power.

Quote
Fpex
btw reading, just now, you blog. Did you calculate what is needed for four noozle as wattage?

At 12V, I reckon 17A for a 1-nozzle printer, plus 4A per extra hot end. I use a 25A power supply for my 2-nozzle printer, which is still set as 12V. At 14V, I suggest 19A for a 1-nozzle printer plus 4.7A per extra nozzle. So a 4-nozzle printer would need 29A @ 12V (348W) or 33A @ 14C (463W).

If I were building a 4-nozzle printer, I would do the hot end temperature control with a board mounted on the hot end. Not only would this greatly reduce the number of cables going to the hot end, it would also make it easier for the firmware to control the total hot end power. Then the peak current demand could be reduced by about 8A.

Edited 1 time(s). Last edit at 01/07/2015 06:13PM by dc42.

---

Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

Interesting. thanks.
I guess I could use the hit end board v2 on your blog on my O2 even if the bed levelling on four heads makes no sense, but the boards can drive the temperature control if I recall correctly,

I now have a switching 12/240 (but I might switch to an atx like for my Mendel), still making a head with includes control has advantages.

My hot end board V2 doesn't control hot end heaters. A different board would be needed for that.

12V power supplies up to 400W are readily available on eBay. One of those should be ok for a 4 nozzle printer, as long as you don't go above about 12V without calculating the actual peak current demand. Don't forget to add the current taken by the water cooling system.

---

Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

I am considering the possibilities taking a big atx and attach the cooling motor to another rail.

Pity your board does not do it, it would be neat to have all head controls in the head.

Edited 1 time(s). Last edit at 01/08/2015 02:59AM by Fpex.

---

----- Making the world smarter @ www.xetal.eu
----- Helping entrepreneurs @ www.fralke.com

I use a 12V LED PSU (quite cheap from ebay, either 30A or 40A) that I have turned up to 14V (it has a voltage adjustment preset). It improved my bed warm-up time considerably. It now takes about 7 minutes to heat up from room temp to 110 degrees C. While slightly quicker would occasionally be nice, I can usually use the time to slice the part, feed in the filament I want, upload the G-file and various other pre-print preparations (such as fetching a beer).

Dave

I like the beer idea :-)

---

----- Making the world smarter @ www.xetal.eu
----- Helping entrepreneurs @ www.fralke.com

DC42, i'm hijacking this thread but i think it is on topic..
would it also be possible to run everithing from 24V on Ormerod1 with internal voltage regulator and then put only 12V regulator on output to your differential sensor board?
This would alow me to use unmodified differential sensor board, and 12V fan without any issues. The heater cartrige and heatbed would be 24V powered.
Also another question, can i send PWMed 12V to the sensor board - to control the fan speed?

Yes you could use a 12V regulator to provide the hot end fan supply. Alternatively, use a 24V fan and change one resistor on the hot end board (the amber LED series resistor) to make the hot end board suitable for 24V.

You should not PWM the negative side of the fan supply, but you could PWM the positive supply. However I don't recommend this as the fan is needed to keep the top end of the nozzle cool. You can use a separate PWM cooling fan for cooling the print, driven from the FAN0 connector on the Duet.

---

Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

Yikes! I would NOT recommend putting 24V through the standard heated bed, or heater cartridge. As dc42 pointed out earlier, the current draw is so much more significant.

Heated bed: resistance 1.3 ohms. With 12V it's 9A / 110W. At 24V = 18.5A / 443W. I don't think the wire or screw terminals are rated at more than 10A or 15A. You would also need a very beefy 24V PSU.
Hot end: resistance 3.5 ohms. At 12V it's 3.5A / 40W. At 24V = 6.8A / 164W. This would be outright dangerous - it would heat up so fast, then probably have problems holding a steady temperature.

13.5V is the MAXIMUM we suggest using with the standard parts. I'd only suggest going to 24V if you have multiple heated beds connected, ie if you wanted to have a larger bed area, which would increase the resistance. There are variants of the heated bed that can take 24V, see [reprap.org] , but ours is not 24V ready.

We use 19V on our Huxley Duo printer, but everything is rated for 19V. The smaller (140mm x 140mm) heated bed has a resistance of 5 ohms, and the heater cartridge 7.8 ohms.

Ian
RepRapPro tech support

I have 24V compatible Heatbed with separate connector for 24V, but of cource the hotend catrige would have to be replaced with 24V.
Then i would add voltage regulator for DC42 sensor board - than i can use the 12V fan and don't need to modify the sensor board.
Is there anything else i should be aware of?