problem with servo motor (video)

[DanOSB]

the axis currently moves 8 inches per rev of motor

we could move the pulley (the one attached to the motor)back and forth with our fingers

our problem is that the motor doesnt have lots of torque..

when i move the axis 2 inches with mach and it doesnt move smooth it is very jerky..

we know its not the driver since we did switch to other driver and it has same problem but for x it doesnt have any problem at all..

specs of our machine.. g320 geckodrive/1125 oz-in dc servo motor from motiontek.ca/SM562570 encoder/ea-d-l-5-fc5 encoder driver adapter/40 vdc

[Al_The_Man]

What type of motors are these Brushed? DCBL? and make of driver.
Did you try without the belt on?
I am assuming you eliminated the possibility of slop in the pulley to shaft when you move it back and forth? IOW does the shaft move with the pulley? it is hard to see from the video.
Is the encoder disc loose maybe?
Al.

[DanOSB]

Al the man: the specs are,.. g320 geckodrive/1125 oz-in dc servo motor from motiontek.ca/SM562570 encoder/ea-d-l-5-fc5 encoder driver adapter/40 vdc


(i just edited my post)

when the belt was removed we can move this motor easily with our hand..

is there a way to test a encoder?

we didnt take the motor/encoder apart (from the motiontek.ca)

there is no slop from pulley to motor shaft at all

[Al_The_Man]

Some through-hole encoders mounted to the shaft with a small set screw, they have been known to come loose.
Just a possibility.
Al.

[DanOSB]

checked the setscrew and encoder it is not the problem..

[mactec54]

DanOSB

Can you set the gain higher, also the voltage may be to low, if you ajust the gain then you will have to ajust the other settings as well, I would try a higher voltage first

[DanOSB]

I tried the gain option and bunch other settings and still same luck.. decided to take another movie..



it shows when i move the axis from 0" to 2" and then 2" to 0" in the end it shows the motor was jerking.. till i put my finger on it to stop the jerking..


hope that info helps..

[krak]

I can't offer much to solve the problem. However, I can tell you I have seen someone loose the tip of a finger by placing it between the belt and pulley as seen in the video. When the machine suddenly spun the pulley, he didn't get a clean cut, it crushed and ripped the tip off. I was told it was the most horrible pain ever fell. That lesson stuck with me. Just a safety warning.

[Al_The_Man]

I would remove the motor and test it on a DC supply such as a 12v automotive battery, you may see some symptoms appear, observe the result when you apply a load to the shaft.
Al.

[DanOSB]

al the man: i just tried your suggestion with 18 volt battery (cordless drill) and the torque of the motor is the way it should be but when i plugged it to gecko without encoder it feels very weak.. and we tested the voltage coming out of gecko it was 39.5 vdc

what heck is going on?

Cheers
Dan

[mactec54]

DanOSB

Like I said in the other post, you are not getting the voltage to the motor, are you sure you have 39.5 at the gecko & not 3.95, your motor worked when you used the 18 volts, so something is not right between the gecko & the motor(wiring), if the gecko is putting out the 39.5 Volt

[DanOSB]

okay ill give it another try tmw.. and it was 39.5 not 3.95 (i wish that was the problem)

i will wire straight from my power supply to motor and see how it behaves

then last resort is gecko i guess.. if wires are good then what other problem could i have?