Rockwell Automation has unveiled an new generation of variable speed drives developed for the global market at a cost of $25-30m.

Rockwell hopes that the FlexiDrive range, its first all-new drives line-up for five years, will give it the edge over rivals such as ABB and Siemens. Rockwell previewed the new drives at its annual Automation Fair in Long Beach, California, in early December.

The company sees the new drives as being vital for it to increase its penetration of the crucial European drives market. Rockwell`s previous VSD ranges have been criticised for being too large and too American for European tastes.

To cater for European needs, most of the FlexiDrive LV models will have built-in EMC filters. The new drives, to be phased in over the coming two years, are split into three families spanning ratings from 0.37kW to 3MW.

All models will share a similar programming structure, making them easier and quicker to commission and use, says Rockwell. The first version to go on sale will be the PowerFlex 7000 medium voltage family spanning ratings from 373kW to 3MW.

These will use a new power semiconductor device, known as the symmetrical gate commutated thyristor (SGCT), to cut losses, to reduce the number of components, and to boost reliability. The PowerFlex 7000 will use sensorless vector control to deliver similar torque control characteristics to those of a DC drive. It is expected to reach the UK by the middle of this year.

The MV drives will be followed later in the year by the low-voltage PowerFlex 70 (0.37-15kW) and the PowerFlex 700 (0.37-30kW) families. One variation being developed will incorporate Rockwell`s Logix processing engine to produce a drive that will also act as a PLC.

• Technical selling points for the PowerFlex family include:
• extensive drive and motor protection, said to make the drives almost "trip-free";
• embedded communications to link them with other factory equipment; and
• patented software to counter the damaging voltages that can be caused by PWM wave reflections. The PowerFlex drives will make their UK debut at the Drives & Controls Exhibition in March.