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I am making a 3D printer on school. It is a Delta version.

The problem is the psu shuts itself down when the heated bed wants to keep it on 55 degrees. and i can't figure it out what the problem is.
specs:
Rambo Board
450 watt psu
200mm Heated bed.

Can someone help me with this problem?

HighDangerr wrote:I am making a 3D printer on school. It is a Delta version.

The problem is the psu shuts itself down when the heated bed wants to keep it on 55 degrees. and i can't figure it out what the problem is.
specs:
Rambo Board
450 watt psu
200mm Heated bed.

Can someone help me with this problem?

It really sounds like a bad power supply, it can't supply the needed current.

What voltage is the PSU rated for, and what is it actually delivering (both are relevant, as if the two are particularly different, it may just be a crap supply, rather than an undersized one), as well as the resistance of the bed. I'm hoping you have a multimeter, and know something about how to use it. Once you know those things, try to pick up a power resistor (not a small one mind you) that will be able to dissipate the appropriate amount of power given it's resistance versus the wattage of the power supply as partially a dummy load, and partially to limit the current the bed is drawing if the PSU will run it as a dummy load (this will reduce the power available to the bed, as you are limiting the current it can grab)

What firmware are you running?
Sounds like it could be this issue: http://forum.repetier.com/discussion/co ... mment_2125
I had a similar problem when I was still using an ATX PSU, setting
#define PDM_FOR_EXTRUDER 0
Worked for me