REO has launched a range of wound components to address what it sees as a trend for drives manufacturers to encourage end-users to source their own equipment such as input mains chokes and filters, DC link braking resistors, and output dV/dt filters, sinusoidal filters and motor chokes.

The REOunity range (above) includes resistive and inductive wound components and is compatible with all VSDs.

According to REO, when the European Electromagnetic Compatibility (EMC) Directive and the G5/4 recommendation were introduced, VSD manufacturers “clamoured to offer radio frequency interference (RFI) filters and chokes as part of a product range complete with ancillary components”.

But recently, it says, drives manufacturers have been distancing themselves from offering anything other than a standard range of wound products with minimum essential EMC requirements. The onus is now on OEMs, systems integrators, machine-builders and end-users to determine the EMC requirements at the site where the VSD is being commissioned.

“This is to be welcomed by VSD users as they are now able to more easily compare like-for-like, without the issue being clouded by basic inverter variations,” says REO.

The range includes line reactors and harmonic filters on the input side, DC reactors or braking resistors for DC links, and chokes, dV/dt filters, sine filters or current transformers for the output side. There are variants for ingress protection (IP) and liquid cooling, which can reduce component size by more than half.

The components are designed to counteract phenomena such as EMC problems, harmonic ripple, voltage spikes, short-circuit currents and interference currents, and to meet the demands of the current EMC and Power Quality directives for clean energy networks, without restricting efficient plant operation.

In addition when a motor is started or slowed down, starting currents have to be attenuated and excess energy dissipated and, according to REO, brake resistors remain the most cost-effective option.