Frequency Converters: VLT® 8000 AQUA

By Danfoss

The Danfoss VLT 8000 AQUA is a dedicated drive for Water and Waste water applications. It has all the good traditional features a Danfoss drive is known for – but on top of that it offers a little bit extra.
This drive is build for both constant torque and variable torque in applications including water, sludge and dosing pumps, aeration blowers, pumps, irrigation equipment, water desalination machines etc. For these applications specific software features have been developed to insure optimum control and energy savings.

Features and benefits

Product range
4 - 45 kW (200 - 240 V)
4 - 450 kW (380 - 480 V)
1.1 - 55 kW (525 - 600 V)
37 - 630 kW (525 - 690 V)
Easy to commission and use
If you know one drive you also know the others.
A Quick Menu guides you easily through the limited programming work left for you to make the drive perfect for the job in your plant.
The VLT 8000 AQUA provides full control of the motor directly from the user interface. “HAND START” enables start and control of motor speed, “OFF” turns off the motor and “AUTO START” shifts control to digital inputs and/or serial communication.
Performance and energy saving
Water and Waste water applications are typically characterised by machines with high power consumption. So in these applications there is also typically a great energy savings potential. Due to the large power machines also a good and precise control of e.g. water pumps is very important to avoid water hammering. These aspects have been taken into account when designing the VLT 8000 AQUA. Among the useful dedicated solutions can be mentioned:
- VLT 8000 AQUA includes both Variable and Constant Torque operation.
- The unique Danfoss Drives AEO function (Automatic Energy Optimizer), makes it possible to save up to additional 5-10% on the energy bill. This function optimises the magnetising current to the motor according the specific load. Consequently valuable energy is saved and not wasted on heating up the air around the motor.
- The VLT 8000 AQUA provides an initial ramp for fast ramping of pumps and blowers. This eliminates damage and reduces wear of the devices.
- With the Fill Mode feature, it is possible to avoid water hammering when starting up the system, i.e. irrigation, water supply etc. This is a closed loop pressure control functionality, which assures that ramping up the speed to reference does not occur before the pipes are filled up.
- The VLT 8000 offers a sleep mode function for increased energy savings in pumping systems. If a pump is running at low speed and not really contributing to the pressure, it is turned off automatically. When the system again calls for pressure, the drive starts up the motor again.
- The VLT 8000 AQUA offers a simple two motor alternation function based on an internal timer in the drive. This is used where a redundancy pump is available and average wearing of the pumps is desired.
- Together with the VLT 8000 AQUA a cascade controller option is available. This enables to operate up to 5 pumps either in standard (1 drive) or Master Slave (up to 5 drives). Lead pump alternation is also possible, averaging the pump wear in the system.
RFI filter and harmonic suppression
The VLT 8000 has built-in RFI-filters for the entire product range complying with EN55011, class A1, A2 and B. Consequently there is no need for costly and space consuming external filters.

A frequency converter generates harmonic distortion of the AC power line. A VLT 8000 AQUA has built-in DC link reactors, which reduces the harmonic distortion to around 40%. For instance, this reduces cable dimensions substantially. The VLT 8000 AQUA complies with IEC 61000-3-2 and 61000-3-4 as well as VDE 0160 as to harmonic distortion.
For further reduction in the harmonic distortion, Danfoss offers external passive 5% and 10% current distortion filters (AHF 005/010).