Drive optimises energy use in an instant

Mitsubishi has launched an AC drive which optimises its energy consumption continuously, even when a motor`s speed or load are changing. According to the company, previous drives could only optimise efficiency during steady speed and load conditions.

The FR-F700 drive can, for example, adapt its performance when materials such as batter change their viscosity during mixing. It will also adapt to changes in ambient temperature.

The drive, first seen at the Hannover Fair, is said to deliver energy savings of up to 12% compared to standard v/f controllers. It is aimed, in particular, at fan and pump applications.

According to Guy Kennet, Mitsubishi`s drives development manager in the UK, 20 years ago, it took a typical drive about a minute to optimise its performance. By the 1990s, the time was down to less than 3s. Now, using a technology dubbed "optimum excitation control", the FR-F700 provides real-time, dynamic optimisation to match the power to the demand at any instant. "It will reset the benchmark for energy efficiency," he predicts.

The new drive (above), which supersedes the FR500 family, will span ratings from 0.37-630kW, with all models sharing the same simple controls. They use new fifth-generation IPMs (integrated power modules) and faster processors.

The drive`s performance can be monitored via a digital display which can show a variety of readouts including savings in kW, kWh, percentage and pence. The detachable control panel can be mounted remotely from the drive.

The F700 has been designed for long maintenance-free operation, with critical components such as fans and capacitors having ten-year design lives. It monitors its key components and warns when they need to be replaced.

A removable terminal block avoids time-consuming rewiring if a drive needs to be replaced. The block is compatible with the previous F500 generation drives.

An RS-485 communication port is standard, and various bus systems including DeviceNet, Profibus, Modbus, Lonworks and CC-Link are supported. A USB interface will be available soon.

The F700 is the first in a new generation of drives from Mitsubishi, with other models due to follow, including full flux vector (the initial model offers a simple magnetic flux vector control), HVAC and high-performance versions.