ac servo choice/advice

[iamspuddy]

thanks
is there any disadvantage to 750w or 1kw on both, as for gearing was it 1:1

please correct me if im wrong but im under the illusion that with the servos and driver kit if it "loses steps" ie out of position it will alarm or something to stop inaccurate turning

[m_c]

thanks
is there any disadvantage to 750w or 1kw on both, as for gearing was it 1:1

How much breaks if something goes wrong :-)
Although too big a servo on too light an axis can cause tuning/stability problems.

IIRC the amount of space available to put a bigger motor on the X-axis is limited, so it's something you have to consider.

I think I went to somewhere around 2:1 ratio, possibly a bit higher.
Steppers aren't fast, and it's unlikely you'd ever run one above 1000rpm (500rpm is probably more feasible for reliable operation), whereas most servos around a similar size will quite happily spin at 3000rpm.
If you direct couple a servo at 5mm pitch, at full speed you'll theoretically get 15m/min, but you're never likely to reach that speed due to the axes being so short, there simply won't be enough distance to accelerate/decelerate to that speed. So it's far better to gear to get better acceleration, and make better use of the servos potential rather than limit how fast it spins.

please correct me if im wrong but im under the illusion that with the servos and driver kit if it "loses steps" ie out of position it will alarm or something to stop inaccurate turning

It all depends on how you program them, but they should do. There will be a following error parameter, that can trigger a fault when a set number of counts out of position is exceeded.