Problems with Servo Help!!!!!!!!

[Scramjet]

Hello

I hooked a servomotor with L pitch belt direct drive, but i notice when i move it in slow speed like 300 mm/min motor does a clog clog clog strange and ugly vibration, like had "steps", is not noticiable in rapid were servo makes a zooom and works like a charm but is slows makes that ugly "vibration"

Im using g320, 1125 oz/in servos from keling and 500 CPR encoders.

Is normal that i have such "steps" or something is wrong there, i heard that servos doesnt have that "steps" that were smoth in movement but now seems that have steps like were steppers!! you know the magnetic click click click.

Is my Gecko 320 tuning? any interference? or the servos are like this, with those steps?

Do i need reduction to avoid such "low resolution"? if i need whats recomendation servos rotate 3000 RPM easily

Thank you

[Al_The_Man]

At very low rpm, DCBL servos will show signs of cogging, but with a DC brushed servo, normally you should not see cogging at all.
Al.

[Scramjet]

Thank you

So means is another thing, not the servos, so no reduction needed.

[Scramjet]

Still can get this working well, low rpms making the system clogs, 3 times more produces good finishing, is the encoder? i think that clogs io feel is the encoder divisions, another thing, think that smooth stepper may help in any way? since works with more pulses

[krazatchu]

Smooth stepper will give you more pulses per second than a LPT port, for a faster top end...
But unless you gear down alot and compensate by speeding up the motor, you won't need more pulses (or need the smooth stepper)...

At 500 CPR quadrature, you will be getting 2000 PPR (pulses per revolution)... lots enough for smooth movement...

I think the problem maybe something else... I would investigate the tuning first...

If you make a major change to the load, like only running the motor by itself to having it attached to a mill table... then you should re-tune the servos...

I had bad bearings on a used Pittman servo that caused some rubbing between the magnets and the rotor... but even then it still ran smoothly, it just made noise...

So check your tuning first, maybe you want to check for electrical interference also...
Are you using shielded cables for both the motor power and the encoder?

Maybe you might want to try different speeds as well, does it stop when you go slower?
If so, it could be a resonance problem but it seems unlikely...

[vipansam]

what type of load u r applying , is it a machine tool slide , may be yours bearing of slide are sticky.

[Scramjet]

Think not, now 2 of my g320s are only with Fault light on, dont know what happend failed with different servo and encoder, now they only have fault light, even if i disconnect encoder the servos doesnt energize and run freely like they use to do when the encoder is not conencted. Im really disapointed with this "servos", i always had ugly cloging even with 4.8:1 reducions! and suddenly they acted rougly and moved by themself like a ghost touched them then .... only fault light.... whats happening any one have idea?

Thank you so much