Which products are affected?
9300 vector 0.37…90 kW SW V7.1
Applications
In the past there was a case in which the earth fault detection has been activated erroneously because the NTC resistors in the customer wiring have been dimensioned too small. As a result, the option to deactivate the earth fault detection has been implemented.
Attention: If the earth fault detection (C0574 = 3) is deactivated an actually occurring earth fault is not detected.
Function description
In the case of 9300 drive controllers the following procedure is executed in order to detect earth faults (OC2) in the motor phases when connecting the mains.
The +Ug potential of the DC-bus voltage is connected for a short period of time to the motor phases U and V. If during this procedure the current is larger than approx. 66 % the valve will be inhibited again and an OC2 trip (earth fault) is indicated. The current threshold mentioned above applies to the Lenze setting, i. e. C0574 = 0.
If C0574 = 3 the current threshold is set to the maximum device current. Thus the earth fault detection is practically deactivated.
