I am having some issues with my servos moving when no signal is being applied.
I have a Teco TSTA-20C Drive with a TSB08751C 750W servo. My troubleshooting has distilled down to running nothing more then 240V 3 phase power to the drive and just the minimum of pins jumped on the CN1 connector so as to enable the servo.
These drives are pretty close reproductions of the Yaskawa Sigma II so I have been scouring the Yaskawa documentation for any helpful troubleshooting tips with little success.
The drives are configured to run in Speed mode. I have jumpered the Analog signal input to the Analog ground on the Drive which according to the teco and yaskawa documentation should provide me with a 0v signal. Additionally I run the auto-offset adjustment so that the drive can compensate for the analog command voltage, which should be 0v as just mentioned.
Following the steps above per the documentation should yield me a stationary servo, but what I have is a very slow bouncing between counts and a gradual CW or CCW servo movement.
On further inspection I see is that offset value being set from the above auto adjustment is around 16mV. Manually setting this value +/-1mv only starts the servo spinning faster in one direction or in the opposite direction all together.
I have checked and even tested an alternate ground connection to rule out any possible grounding issues.
Some of the questions I am asking myself are: How sensitive are these or the Yaskawa drives to noise in the input power? Are filters absolutely necessary with these Drives/Servos or other AC powered servos? Are the problems I am having related to external noise or something internal to the drive? I am focusing mostly on line noise due to the fact that these problems only occur when the servo is configured in a mode to accept analog +10/-10V input.