Connection between mosfet and heat bed and ramps1.4

3D Printing
1

my heatbed is silicion 450 watt
and power supply 360 watt
so i should buying another powersupply above 500 watt for heat bed

2

You definitely need a larger power supply than the bed will draw. How much larger depends on what else you are powering.

If you want to use a separate power supply for the bed, you will need a separate MOSFET board, I believe; I don’t think that the ramps v1.4 has a separate bed power supply.

Are you running 12V or 24V?

3

So long as the bed MOSFET is a conventional N-channel type it will be ok so long as both supplies have their 0V lines connected to the board 0V (-) rail.

The +V for the bed should go directly to the bed +ve line, not to the control board. The bed -ve line then goes to the mosfet bed- connector as normal.

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4

Oh, that’s a good point. Connect positive direct from the power supply to the bed, and use the MOSFET to switch the negative to shared 0V / GND.

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