48V Duet3(4?) to complement future Duet Motors?

T3P3Tony

@TLAS as @dc42 says v1.02 6HC is 48V as are the latest 3HC. The 1HCL and the larger closed loop motors will also be 48V.

jens55

When making the Duet 48V capable, what was the anticipated use case? Was it just for CNC purposes?
I can see how 48V would be nice for motors but what do you do for hot end heater cartridges. in 3D printers? I have only seen those in 12V and 24V. Do people end up generating 24V externally just for the heaters?
Are there plans for a 48V 1LC tool board?

T3P3Tony

@jens55 for people who want to run motors at higher speeds, they benefit from the higher voltage. I believe there are already 48V heating cartridges available from a few suppliers and we support using 12V fans from the onboard 12V power supply.

At this point we don't expect a large demand for tool boards in their current formfactor to need to run at 48V.

Larger machines (the normal use case for 48V) often need multiple power supplies anyway so i expect some configurations for both 24V and 48V in that case

juliann

@T3P3Tony When this new Duet motors will be available?
Thanks!

T3P3Tony

@juliann we are aiming for Q2 for the first of the range.

juliann

@T3P3Tony Thanks, that's great, where can I get more information about them? is a brochure available?

T3P3Tony

@juliann I will announce more on the forum when its available.

o_lampe

@jens55 said in 48V Duet3(4?) to complement future Duet Motors?:

what do you do for hot end heater cartridges.

In config.g you can reduce the power for a 24V heater cartridge to 0.5. That's what was done in early FDM days, when the 24V controller boards where new and 12V cartridges were the only available ones.

jay_s_uk

@o_lampe but thats definitely NOT recommended as you're still feeding 48v to the cartridge!!!!

o_lampe

@jay_s_uk The heater is just a resistor with a max. power value.
It doesn't care about voltage so much when the duty cycle is limited to 50%.
Maybe PID tuning is difficult?

oliof

@o_lampe Ohm's Law tells me you'd need to go to PWM 0.25 at a maximum, and I am still with @jay_s_uk that it bears considerable risk.

dc42

@jens55 it's possible to buy 48V cartridges to fit hot ends that use cartridges.

oliof

@dc42 I would still suggest to get more current on the 12V rail in a future revision, BTT boards like the Octopus allow 4 / 8 A on 12V.

dc42

@oliof we'd like to do that but it's expensive to generate 12V from 48V and also difficult to meet FCC and CE EMC regulations. I don't think any other boards support 48V input without requiring a separate 24V input to power the lower voltage components.

jay_s_uk

@dc42 thats correct. all the other boards require a 24v input to generate the lower voltages with 48v only used to drive the motors

o_lampe

@oliof I agree about ohm's law telling us to use only 25% duty cycle. My mistake!
I've use a 12V bed heater at 24V without problems using this method, but overpowering a cartridge might be a different story.
Just wanted to point out, that a resistor doesn't have a voltage limit per se.

o_lampe

@jay_s_uk
What about using a big 24V PSU and feed the motors from a DC-DC boost converter?
I'm using a few different boost converters for several tasks and they never failed me so far. ( 100W - 600W are cheaper than a second PSU)

jay_s_uk

@o_lampe that may work assuming the boost converter and PSU can handle it.
For my voron 2.4 i went with a separate 48v PSU. The LRS-200-48 aren't very expensive https://www.printyplease.uk/LRS20048?search=48v

o_lampe

@jay_s_uk
I'm using a separate 48V supply on my CNC, too. I always forget to switch it on before powering the 24V PSU. The TMC5660 drivers don't like it and quit responding.
With a boost converter, I only need one mains-socket/cable/switch...and ground-loop issues are no problem anymore.

oliof

@o_lampe the resistor does not, but the insulation may!