Duty cycle.......it has a duty cycle of 60% at an efficiency of 85% at 40 amps.......Also has a heat safety cut out switch........
The plasma cutter wingdings could be small gauge or aluminum and this will affect how long the machine can work.........Bought a cheap welder and was told they weren't that good but i foolishly thought that because the job didn't require continuous welding i would be ok..........aluminum internal windings, meant the machine would cut out after no more than 30 sec of welding then i had to wait for it to cool down, (several min), then another 30 sec welding.............finished the job eventually and the welder went to the tip.....
The duty cycle is a count of 10....... 60% duty cycle at 40 amps means the cutter should work for 6 min and rest for 4 min being used at 40 amps..........at 50 amps that 60% would drop a lot lower, (doesn't state in the add so cant tell), and also the efficiency rate would drop as well.............power supply also has an effect on the manufactures claim of duty cycle and also manufactures claims are usually on the high side.
If the cutting amps are dropped to 20 amps the duty cycle will rise and could be as high as 80/90%.........Again no stats in the add......
This information should be in the paper that comes with the welder.
https://weldinganswers.com/understanding-duty-cycle/
As an example; Bought a portable welder, choice of 2 was a 130 amp and 170 amp, Both run of the single phase household power),
130 amp has a 5% duty cycle at 120 amps......25% at 50 amps..................
.Bought this one:
170 amp welder; 130 amps at 60% and 80 amps at 100%. as most of my welding would be in the 80-100amp range and not ever having very long continuous welding situation, the duty cycle was plenty.