6.7.2. Ground fault protection
The drive is equipped with an internal software ground fault protective function to protect the drive
against input and output unbalanced currents. The response threshold can be set from 0% to 30%
of the rated current (G.11.3). For further information, see Programming and Software Manual.
This function is not intended to work as a personnel safety or fire protection, so an external
protection must be provided to ensure that a substantial ground fault current is promptly interrupted.
The SD700 drives are suitable to operate with RCD components Type B, if it is required. The EMC
filters and long motor cables increase the ground leakage currents so the threshold response of the
protection should be adjusted according to the relevant plant conditions. For additional information,
contact with Power Electronics.
6.7.3. Motor thermal protection
The drive includes a motor thermal protection that based on the motor performance parameters
mathematically calculates the thermal reservoir of the motor. When this reservoir is reduced below
the limits, the drive automatically stops the motor. The thermal model sensitivity could be configured
in parameter G2.7, for further information consult Software and programming manual.
The drive includes as standard a PTC connection that permits to monitor the motor temperature.
Once connected and configured the drive could either stop the motor or generate a warning signal.
6.7.4. Others
The drive implements additional motor and drive protections such as power-loss ride through,
automatic fly restart, high and low input and output voltage, pump overload and underload... For
further information, consult Software and Programming manual.
6.7.5. Safety Stop Function
Safe Torque Off (STO) allows the drive output to be disabled so that the drive cannot provide power
or generate torque in the motor. The STO safety function has been certified by Tüv Rheinland
according to IEC/EN 61800-5-2. For further information, see section 7.3.
6.8. IT grids - floating earth drives
When planning an IT grid electrical installation select the drive for floating earth operation. Check the drive
reference to ensure the correct drive selection.
IT grids must be equipped with an insulation monitoring system. To set the parameter settings, consider
that the drive has inherent very high impedance, even when a large number of drives are working in parallel
on the same IT system.
It is recommended the installation of surge arrester to ground to protect against transient overvoltages. The
surge arrester must have rated voltage greater than the drive voltage range to prevent its operation during
normal conditions.
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