Duet board track thickness? for the mosfet, MAX Amps

Hello

I'm trying to know if I can demand from the Bed_heater mosfet 15AMPS
Is the board capable?

If I know the Trace Thickness I can determine this, but is not in the documentation

If the Trace Thickness is 35micrometers, then the max current is only 6 or 7Amps
But if the Trace Thicknessis 70micrometers, then the max current can be 27Amps

Since most beds are 10-12 amps @ 12 volts, I'd say it's a safe bet that 6 or 7 amps isn't the limit. The limit is also going to depend not only on the trace thickness, but also what the duty cycle is and the width of the trace is.

Hi Luis

I replied by email but will put this up here in case anyone else searches for it.

The trace thickness is 70uM on the oter layers and 35uM on the inner layers. The FET data sheet is here:


An analysis of the heating with a 10A draw, in still ambient (25C) air is on our blog duet-fet-psu-and-stepper-driver-testing, only a 15C temperature rise. With 20A we will see a 50C temperature rise. for 30A you would need to use some very effective heatsink and forced air cooling so if you want to use that much I suggest using a solid state relay (if you need fast switching) or a normal 12V relay if slow switching and cost is a concern.

Cheers

Tony

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