Toroidal power supply and Gecko stepper questions

15A termistors ???
That would require an RC timer and a relay, nowadays used on all the high power electronics even the chinese CO2 welders have it.

rodw wrote:

This can be solved by adding a Thermistor that prevents the inrush.

I have not had much luck with thermistors, but it is pretty simple to do it with a resistor and a relay if you add a bit of magic. And that magic is HAL.

What my lathe does is power the DC PSU through a 250W power resistor. It helps that the 8i20 drives report-back the bus voltage. (as does the STMBL). But this could just as easily be a software timer.
Once the bus voltage is near the nominal value, HAL sends an output to turn on a relay that bypasses the resistor.

Note that the resistor is not nearly big enough to run the machine full time, if the relay fails open-circuit then the resistor will too. But that's unlikely as they typically fail closed-circuit and then all that happens is that the RCD trips next switch-on.

My mill uses a custom 555 timer circuit. But only because I was younger and stupider.