Retrofit Precix 3 Axis Gantry Mill

 I also attached some images and a schematic of my current controller setup.

Thx,
Armin

 

Please recheck this. The older componant marked as "SSR Relais" in the first post photo is an Electromagnetic Relay .

just checked,
you are right it is a mechanic relais thx. i labeled it wrong. but i was just for switching auxiliary devices (PC)

So now i tested several scenarios, changed the ssr to wtho channels- one for neutral one for phase,
also added two thermistors (neutral and phase) in front of the ssrs. seemed quite promising.
-This was more or less the original setup.
I also disconnected all loads . Continuous current behind the ssr:  less than 1 Amp. 
It seems better but still issues with breakers.
Then i did a test with an inrush current meter (while switching the ssrs) mostly no reaction, but with a reduced switching cycle
got "better" results. 8,14 and then  39 Amps!  guess the bouncing  effect when switching in less than a second "pumped" the induction of the toroidal- mystical induction, it is still a miracle to me- it was off-on-off in a short timeframe so it just looked to me like turning off the PSU?  
This is all just my cheap theory, but i still like to go with the toroid before i give up and switch to switched PSU's  

So my ideas:
-Next i will try the light bulb test. Lets see what it does. Not sure if can still find one.
-I will try to debounce the switch or should switch it via mesa?
-The blown ssr was in fact cheap chinese but i would not blame it (the 40A specs were wrong maybe). The new ones are alive so far. 

The core of the toroidal transformer can keep some magnetisation when turned off. Turning on in the "right" moment so existing magnetisation and current are in the same direction will drive the core into saturation and look like a short circuit from the outside (for a short moment, probably less than half a period). Thermistors should take care of that, but they won't limit that much if they are still hot. That is all expected. There are explicit toroid transformer switching devices that really take care of the problem, i.e. kill the remanent magnetisation before turning or something like that.

The really strange thing is breakers tripping when turning off.

i think my switch controlling the ssr is "bouncy" - der schalter "prellt"- so there is a short on cycle in-between, so it just looked like turning off. i try to delay the switch now - debounce. lets see...

ok, switching the ssr rapidly on/off will definitely trigger the "toroid transfo looks like short circuit" situation, so that is settled then.