What is the safest way to wire two power supplies to power the Duet and a heatbed, including fuses and switches? Is an external MOSFET required on the bed?
I have a 24V coreXY printer with LEDs, a single hotend, and a 300mm bed. I noticed the fan for the 350W Meanwell PSU kicks on often and seems to struggle with bed temps over 100C. It looks like PSUs over 350W jump to the $100-150 range. Instead, I bought a second smaller 24V/150W to power the Duet, LEDs, motors, and hotend for $15.
Originally I was going to purchase an external MOSFET for the bed but I believe there is a way to directly connect the larger PSU ground to the Duet heatbed output ground, and the heat bed in between the Duet and PSU since I think the Duet does the PWM control on the positive heatbed positive output.
Also, I would like to use one switch to turn both PSUs on if possible. I don’t think it is safe to use one of the standard “plug, fuse, switch” combos most printers use since it would be one fuse for two PSUs. I believe the correct way would be to use a plug with a switch then make three Y cables with their own fuse to split the incoming power between the two PSUs.
I’d like to verify the correct wiring before making a house fire though are there any schematics available? Thanks!