Specifically designed to minimise the incidence of pump blockages caused by fouling and to clear any blockages that do occur without the need for manual intervention, the new software provides anti-rag and automatic flushing options, both of which can be configured by users to match the needs of their application.

Operating in conjunction with the PI control software that is a standard feature of all NX series drives, the anti-rag feature automatically senses when the pump is becoming blocked. It then reverses the pump to clear the blockage before restoring normal operation. The user can set the time for which the pump runs in reverse and the maximum reverse torque, which is often higher than the pump’s normal operating torque.

The number of anti-rag (reverse/forward) cycles that the drive will perform in an attempt to clear a blockage can also be set. This procedure is designed to clear a high proportion of blockages but, if the preset number of anti-rag cycles is exceeded and the blockage is still present, the drive trips to prevent damage to the pump.

To assist users in assessing the benefits of using ac variable speed drive technology, all NX series drives have the ability to calculate and display the value of energy saved compared with fixed-speed motor operation.