Toroidal power supply and Gecko stepper questions

thefabricator03 wrote:
Only problem I had initially was the current draw when I turned on the power to the toroidal was too much for the circuit breaker I was using and it would trip. I replaced the circuit breaker with a "D"curve breaker and all is well.

This can be solved by adding a Thermistor that prevents the inrush. As it gets a bit hot, the thermistor resistance falls so the current increase is gradual. When I put in my toroids the supplier gave me a couple and I never trip a circuit.

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.

No eBay APP ID and/or Cert ID defined in Kunena configurationI use these on toroidals

tommylight wrote: 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.

Nah, super simple when th eguy designing th etoroid is speccing the thermistor

This kind of thing:

www.digikey.com/en/products/detail/ametherm/SG32/4862345

PCW wrote: This kind of thing:

www.digikey.com/en/products/detail/ametherm/SG32/4862345

Yes exactly. I thought it was a cool trick

Shown here installed. Here we used 2 x 32 volt toroids because they were available. 64V 20 amp out. No need for any other circuitry.

rodw wrote: Shown here installed. Here we used 2 x 32 volt toroids because they were available. 64V 20 amp out. No need for any other circuitry.

Attachment not found

Rod - What motors are you running? Are you using all the same motors and LAM drivers? Or do you have a mixture?

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.

I like how the thermistor is installed into the terminal. It makes for a clean installation.