Centroid Community CNC Support Forum

I am having some fun trying to set up a ACS355 VFD on a permanent magnet servo motor. For spindle control.
The manual says it can do it. The ABB technical guys say it can do, but I can't get it to work properly!

I have read the setup guide and manual several times, set all the essential parameters for a permanent magnet motor. It has run its self tests and self tune. When I try run it, the frequency is incorrect for the RPM value I have set. The motor turns but it is jerky. The current keeps climbing until I shut it off. Like it thinks the motor is heavily loaded and cant get up to speed.

I am waiting for ABB support but thought I would ask if anyone had any ideas or advice?

Right now it is just mains and the motor wired and controlling off the front panel.

Thoughts?

there is probably still a parameter set wrong somewhere. are you using encoder feedback?

There are so many parameters that one is bound to be set wrong!

I am using encoder feedback to the Oak but not directly to the motor drive. Although encoder feedback to the drive is an option apparently.

I found a soft start option where it seems to bias the normal control at startup and use a fixed current. The motor turns at the correct RPM but is a bit notch at lower speeds. Although once you go above the soft start range, it goes back to being unable to control the motor again. I tried changing the PID settings but there is no change. In normal mode it always just gets stuck at 1.6Hz and starts ramping up the current until I have to shut it off.

Sorry, I know I didnt post a lot of details but they ate probably only useful to someone with a lot of knowledge on this drive.

Just a follow up post on this. I tried this drive with an encoder interface. With all the ABB technician help, we just could not get this drive and motor combo to work. I was able to get smooth stable low RPM once the encoder was used. However, the torque was so weak that you could stop the motor with your hand easily. That is with the auto tune settings. I massively improved this with PID tuning, but it was not good enough. But, the high gain settings required to get a fast torque response resulted in over current faults when trying to accelerate the motor quickly. Also encoder faults on fast acceleration. So, for a simple constant speed application with slow changing torque demand and slow speed ramp up and down, this drive can adequately drive an AC servo motor. But not suitable for spindle application...

Send me specs of u r motor.

Aamir

aamir wrote: ↑Thu May 06, 2021 9:51 am Send me specs of u r motor.

Aamir

Ok, we definitely need to talk! That is the exact same machine I am converting. In fact it is the only other one I have ever seen!