Danfoss has introduced a pump-specific drive for the water industry based
on its VLT series drives. The VLT8000 'Aqua' offers both quadratic and
constant torque performance and is based on the Danfoss VVC+ control
strategy, which enables the motor to be run at full load/speed without
any motor de-rating requirement. Energy saving in pump applications is
achieved by means of automatic energy optimisation software, which
actively controls the motor flux in response to load demand. Other pump
application related features include duty/standby operation (the drive is
tuned to both duty and standby pump motors and switchover is initiated by
a timer); a 'pipe-fill' mode to avoid water hammer, and cascade control
for controlling multi-pump installations.