Hi,
I do need the information about the output ( max current and voltage) from the K8400 mainboard, also the thermal controll input spcifiactions.
Is a heating bed comming from Vellemann in the near future?
Thanks
Power supply is 15V.
In theory, the power supply can deliver an extra 3A, however we’d recommend an external power supply, to avoid driving the supply to its limit.
Furthermore, 15V * 3A = 45W, which is a bit on the low side for optimum heating and warm-up speed.
NTC should be 100K
At this time, a heated bed is not scheduled.
does it mean a larger PSU 15V/16A will be ok, without problems for the mainboard?
Mainboard output is also 15V or is it regulated to 12V?
Yes, mainboard also requires 15VDC.
velleman, I think what preuswo is asking (but just guessing here) is that if he/she adds a 16 A PSU, what kind of current can be drawn from the mainboard (to a heated bed)?
Vertex draws peaks up to 7A, so in theory there are 9A remaining for the heated bed, if you add a 16A PSU.
And I guess that the MOSFET on the mainboard can handle this without problems…?
At 9A, the MOSFET would have to dissipate 1.2W, which is too high.
Do you really need a 9x15= 135W heated bed?
Just a question to Vellemann, How did you achieve the 7A peak current?
I calculate:
4* Stepper peak current of 1.7 A (specification of the stepper motor) = 6.8 A
2* 33W Heat cartridge : 2.2 A = 4.4 A
Power consumption of the electronics: estimated 0.5 A
In sum about 11.2 A.
Where is my mistake?
Hi,
Im new to this forum but why dont you just use a SSR instead of the mosfet pcb? Easier and cleaner look and cheap to get in China 
In the same spirit, what about using a simple toroïdal transformer (1 screw, low EMI, high throughput) and a simple SSR (insulated, synchronized, one chip, not so expensive) ?
[Mode Oooops ON] Forget it: an industrial power AC/DC converter is cheaper than the transformer itself [Mode Oooops OFF]