SK Commander VFD Parms

tommylight wrote:

@Snowwy,
Can you please check the torque charts for the "servos" you got?
Sorry, but i still get very P.O. at "clearpath servos" as i am sure they were selling closed loop steppers as servos a few years back.
Thank you.

It looks like they could still be Tommy based on the torque curves.
I would expect servo motor torque curves to follow something like this


Ref: www.orientalmotor.com/servo-motors/techn...-motor-features.html

You can see here the torque is constant regardless of speed until it gets to 3000 rpm
The clearpath torque curves follow the more normal form of a stepper motor.

tommylight wrote:

I can not fathom why would they or anyone make servo systems imitate a stepper system, seems unreasonable on many levels and waste of potential.
Sorry for steering off topic, and thank you, all.

 X 2
I'm not saying they aren't good motors but its a misleading analysis designed to keep the so called inferior stepper in the resonance zone.
Glosses over and ignores a lot of engineering on the stepper side..
I looked at one of our motors we did detailed engineering for. A nema 24 capable of 60 m/min rapids with a 3:1 reduction and on the X axis, its maximum power requirement of 9.81 watts. It would be rare for a motor that size  to need 100 watts. We overrate steppers using Lam's step boost technology., not underrate them and we never loose steps.

snowgoer540 wrote:

He did loosely cover that in the video I linked "high torque at low speed to allow driving lower speed applications without gearing". .

Clearly they have been designed as a drop in replacement dfor steppers. If a machine was engineered from scratch, thye would have significant limiting factors. It would be a rare case where gearing is not required in any motion application. Sometimes its not obvious as its driving a ballscrew. Hight torque at low speed is advantageous for plasma as it alows faster Accelleration. A more conventional servo has constant torque across the whole rev range. We don't need 3000-5000 rpm servos so gearing down make sense to amplify that torque at all speeds. Also the more conventional servo can handle 200-300% over rating for short periods (as the graph I shared shows),  We only need 30 ms to get to 10 m/sec at 0.5 G accelleration so that works to advantage.