New AC Drive Series Targets Water, Wastewater Applications

Danfoss Inc.'s Water & Wastewater Division has introduced the VLT" 8000 Aqua, a global AC Variable Frequency Drive series that was developed specifically for the needs of the water and wastewater market. The new drive incorporates optimized design features and performance capabilities that are uniquely appropriate for water, wastewater, irrigation and reverse osmosis systems.

The VLT 8000 Aqua series is designed for 3-phase AC motors from 1 to 600 hp. A key feature of the drive design is its ability to provide maximum efficiency under all conditions. If an environmental event occurs, such as elevated temperatures or phase loss/phase imbalance, the new drive automatically derates output, as opposed to simply "tripping-out," which helps maximize uptime.

Unlike previous drive designs, the VLT 8000 Aqua can function as the only adjustable frequency drive series for an entire water or wastewater plant. Features include the use of a single user interface with HOA (hand-off auto) across the entire drive series; energy-saving performance through a proprietary AEO (automatic energy optimizer) design for VT applications; and optimized constant torque (CT) functionality.

The drives are designed to be retrofit into existing applications using standard motors, and feature an AMA (automatic motor adaptation) design that ensures optimal usage of any motor.

The new drive series features line voltage variation tolerance of +10 percent to -15 percent without loss of output torque, and incorporates Danfoss' Voltage Vector Control principle, which eliminates the traditional need for motor derating. A sleep mode automatically turns off motor operation when demand drops below a minimum set-point and provides a boost function to prevent short cycling. The drive operates with up to 1,000 feet of motor cable connected without requiring additional filters and can be programmed to auto-restart in the event of power loss. Harmonic distortion protection is provided through a built-in DC-link filter.

The VLT 8000 Aqua offers a multi-lingual display and programming in 39 real process units (gpm, psi, bar, ppm, etc.). A Quick Menu assures operation within minutes.

For better pump control than is the industry norm, the drives offer motor alternation control of two pumps or blowers, a pipe fill mode, and an optional cascade pump controller card that operates up to five pumps or blowers in parallel, in either a variable speed configuration or by mixing variable and constant speed.

The series drives communicate via SCADA, telemetry, PLCs and other controllers using extensive I/Os, standard RS-485, optional Profibus, Modbus RTU, and DeviceNet communication cards.

The UL, cUL and CE-listed VLT 8000 Aqua drives are available in Chassis, IP20 (protected chassis), and NEMA 1 or NEMA 12 enclosures with horsepower ratings of 200-240 vAC input, 5 to 60 hp; 380-480 vAC, 5 to 600 hp; and 550-600 vAC, 1 to 300 hp.