Corrected from:
- i700 servo inverter V01.09.03.10964
Response of the new version:
The influence of the slip compensation, which is, if necessary, still available when the motor comes to standstill, is ramped down in only one second now (ramp slope: 1x rated motor slip per second) independently of the setting of the filter time constant of the slip compensation.
In the case of passive loads (only friction, no weight or spring forces), there will thus no longer be any unexpectedly long overrun after stopping.
What happens?
The motor continues rotating at low speed for an unexpectedly long time after the setpoint speed has already reached standstill.
When does this behaviour occur?
The behaviour occurs when quickly stopping the motor down to standstill in the V/f characteristic motor control mode with active slip compensation.
The overrun behaviour is caused by the influence of the slip compensation which is, if necessary, still available after reaching standstill (speed setpoint = 0). The overrun time is proportional to the set filter time of the slip compensation (0x2B09:2).
Background:
As a matter of principle, with asynchronous motor operation there is a load-dependent deviation (slip) between actual speed and setpoint speed. The slip compensation is used to compensate for the speed deviation. Due to operation without feedback, there is no measured actual speed value available for this. Compensation is based on a computer simulation of the operating state of the motor implemented by means of a motor model.
- i700 servo inverter
Short-term measures:
The overrun time can be reduced by reducing the filter time of the slip compensation under 0x2B09:2.
Evaluation/recommendations:
None.
