Efficient Networks S120 manual Description of Vdcmin control, 73RZHU

Vector control 4.9 Vdc control

Description of Vdc_min control

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Figure 4-14 Switching Vdc_min control on/off (kinetic buffering)

In the event of a power failure, Vdc_min control is activated when the Vdc_min switch-in level is undershot. This controls the DC link voltage and maintains it at a constant level. The motor speed is reduced.

When the power supply is restored, the DC link voltage increases again and Vdc_min control is deactivated at 5 % above the Vdc_min switch-on level. The motor continues operating normally.

If the power supply is not reestablished, the motor speed continues to drop. When the threshold in p1257 is reached, this results in a response in accordance with p1256.

Once the time threshold (p1255) has elapsed without the line voltage being reestablished, a fault is triggered (F07406), which can be parameterized as required (factory setting: OFF3).

The Vdc_min controller can be activated for a drive. Other drives can participate in supporting the DC link, by transferring a scaling of their speed setpoint from the controlling drive via BICO interconnection.

Note

You must make sure that the converter is not disconnected from the power supply. It could become disconnected, for example, if the line contactor drops out. The line contactor should have an uninterruptible power supply (UPS), for example.

Drive Functions	135
Function Manual, (FH1), 07/2007 Edition, 6SL3097-2AB00-0BP4