V/f-characteristic control: function 'catching' (flying restart) does not work with high-power motors (corrected from V01.08.00)
Corrected from:
Servo Inverter i950 FW: from V01.08.00
Response of the new version:
The catching function now works as expected even with large motors with electrical time constant > 0.2 s.
The timeout monitoring of the flying restart function has been adapted to the rotor time constant of the motor, so that the catching process is no longer interrupted unintentionally.
What happens?
Flying restart function:
When switching to a coasting motor, the overcurrent monitoring responds, error message short-circuit.
The flying restart function enables the inverter to be released and connected to a motor that is still spinning (rotor in rotation). The current required rotating field frequency and voltage for switching on must be determined.
Due to a SW error, the capture algorithm is prematurely aborted by timeout monitoring. Instead of the actual rotor frequency, the parameterised start frequency (0x2BA2) is used. Depending on the frequency difference between the motor and the inverter, the motor current can rise sharply. The current limiting controller (Imax controller) acts on the motor current via a frequency adjustment to limit it to the set maximum current. However, if the frequency difference is too great, this is not always successful and the overcurrent monitoring may respond.
When does the behaviour occur?
Motor control type V/f characteristic control (VFC)
High-power asynchronous motor (ASM) with an electrical rotor time constant > 0.2s.
Interception function with setting 0x2BA0 = [2]: Catch mechanism "Without acknowlwdge or blocking".
Release of the inverter in case of a whirling motor shaft.
