DC parker drive current decrease to zero A

The drive is 590+.

The drive was already stopped about 8 months.

Now starting the motor underload give us this periodic fluctuation. Our charge is a cylinder filled with material, the normal variation of current is in definite band. But the problem is the decrease till zero value. We suspect that the cylinder was mechanically deformed.

We use another DC drive and we get the same phenomena and with no alarm.

In our case we use bypass of speed loop, we don't use a speed feedback that's why I'm asking about the IaDmd unfiltered, it should be constant or variable?.

Ah, that makes more sense.  If you are bypassing the Speed Loop, that value should be constant.  Another thing you might check is your analog input.  I assume that is what is providing your current setpoint?  Maybe there is a damaged spot in your command wires that periodically cuts voltage to the setpoint input.

When we do a monitoring in diagnostic menu we find that the IaDmd unfiltered is inconstant and it decrease to minse values, is exactly when the current decrease.

About the speed, we get the speed feedback from the drive and it didn't come to zero, it just fluctuates in the monument of zero Ampere.

Now we need to get a technical interpretation to confirm that we have a mechanical obstacle. We are confused about this issue especially all we know that in mechanical load problem, the current increase not decrease.

Another question, when the material inside the cylinder made the motor rotate by inertia, in this case we get like this phenomena?

Thank you so much Mr Daniel

Again, I think you might want to check on your setpoint.  Since your drive is not doing speed control, current demand should never suddenly drop to zero.  I suspect that your current setpoint, probably coming in on an analog input, may be dropping to zero.  There are still ways this could be a mechanical issue, but I think we should check the setpoint first.

OK Sir thank you so much. Now we are trying to change the loading material, the current doesn't drooping to zero. It seems OK. Maybe it was a mechanical issue. We will continue to check. Thanks a lot.

There may be more going on.  If you have an external control loop through a PLC, then this could still be some kind of mechanical issue.  You would want to track down the entire signal chain to understand where the problem is.