Your feedrates are very (TOO) low.... plasma is all about acceleration too.... becuase the cutting current is constant and you need to change direction, you need to be able to have you machine accelerate and decelerate its axis as fast as possible. or you will end up with rounded corners and lots of dross.
How are you driving this plasma table?
What ampage stepper motors are you using?
What stepper drives are you using?
I started off with a load of ..... well not very good stuff and you end up buying twice to replace out the poor stuff to get the cut qulity where you want it.
Kind of like the old addage.... "measure twice, cut once"....... "design once, buy quality, never look back".
The 900mm per min is typically my G1 cut speed.
I just can not get a lot faster so it is not possible with my set-up size 23 steppers on X and y and type 17 on Z. Currents around 3 Amps X and Y and just under for Z, all from 24Volts supply and control max rating is 24Volts. Again Chinese set up cira £60 purchase.
I am aware it is cheap but it will have to do.
Table size is 760 by 460 ish mm. All home made and very, very budget.
I will have a read through the information you have provided, yes I have the manual for mine rated voltage is 100 Volts in the user guide.
The input is 4.7KVA at rated output of 40 Amps, so really wants a 22Amp supply but duty cycle is 60% at that those figures.
I need to run the machine under 25 Amps if I can reasoning is it is on a 13 amp socket.
220 Volts x 13Amps = 2860 KVA * 0.85% efficiency I have 2431 KVA available, 100 Volts rated so around 24 amps cutting current.
I can push a bit higher but the garage supply which is really only rated at 20 Amps has to power PC, lights and a compressor.
Thanks for the rest of the information I will read through the posts you have listed, thanks for that.
Adrian
p.s. even your modest feed rates are to fast for me, it is a case of do what I can for fun.